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LamoTRIgine

Pronunciation

Pronunciation

(la MOE tri jeen)

Index Terms

  • BW-430C
  • LTG

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Kit, Oral:

LaMICtal ODT: Blue Kit: 25 mg (21s) & 50 mg (7s), Orange Kit: 25 mg (14s) & 50 mg (14s) & 100 mg (7s), Green Kit: 50 mg (42s) & 100 mg (14s)

LaMICtal Starter: Blue Kit: 25 mg (35s)

LaMICtal Starter: Green Kit: 25 mg (84s) & 100 mg (14s), Orange Kit: 25 mg (42s) & 100 mg (7s) [contains fd&c yellow #6 aluminum lake]

LaMICtal XR: Green Kit: 50 mg (14s) & 100 mg (14s) & 200 mg (7s) [contains fd&c blue #2 aluminum lake, polysorbate 80]

LaMICtal XR: Blue Kit: 25 mg (21s) & 50 mg (7s), Orange Kit: 25 mg (14s) & 50 mg (14s) & 100 mg (7s) [contains polysorbate 80]

Generic: Blue Kit: 25 mg (21s) & 50 mg (7s), Green Kit: 50 mg (42s) & 100 mg (14s), Orange Kit: 25 mg (14s) & 50 mg (14s) & 100 mg (7s)

Tablet, Oral:

LaMICtal: 25 mg, 100 mg, 150 mg, 200 mg [scored]

Generic: 25 mg, 100 mg, 150 mg, 200 mg

Tablet Chewable, Oral:

LaMICtal: 2 mg [DSC] [contains saccharin sodium]

LaMICtal: 5 mg [scored; berry flavor]

LaMICtal: 25 mg [berry flavor]

Generic: 5 mg, 25 mg

Tablet Dispersible, Oral:

LaMICtal ODT: 25 mg, 50 mg, 100 mg, 200 mg

Generic: 25 mg, 50 mg, 100 mg, 200 mg

Tablet Extended Release 24 Hour, Oral:

LaMICtal XR: 25 mg, 50 mg, 100 mg [contains polysorbate 80]

LaMICtal XR: 200 mg [contains fd&c blue #2 aluminum lake, polysorbate 80]

LaMICtal XR: 250 mg [contains fd&c blue #2 aluminum lake]

LaMICtal XR: 300 mg [contains polysorbate 80]

Generic: 25 mg, 50 mg, 100 mg, 200 mg, 250 mg, 300 mg

Brand Names: U.S.

  • LaMICtal
  • LaMICtal ODT
  • LaMICtal Starter
  • LaMICtal XR

Pharmacologic Category

  • Anticonvulsant, Miscellaneous

Pharmacology

A triazine derivative which inhibits release of glutamate (an excitatory amino acid) and inhibits voltage-sensitive sodium channels, which stabilizes neuronal membranes. Lamotrigine has weak inhibitory effect on the 5-HT3 receptor; in vitro inhibits dihydrofolate reductase.

Absorption

Immediate release: Rapid and complete

Distribution

Vd: 0.9 to 1.3 L/kg

Metabolism

Hepatic and renal; metabolized primarily by glucuronic acid conjugation to inactive metabolites

Excretion

Urine (94%, ~90% as glucuronide conjugates and ~10% unchanged); feces (2%)

Time to Peak

Plasma: Immediate release: 1 to 5 hours (dependent on adjunct therapy); Extended release: 4 to 11 hours (dependent on adjunct therapy)

Half-Life Elimination

Immediate release: Adults: 25 to 33 hours, Elderly: 25 to 43 hours; Extended release: Similar to immediate release

Concomitant valproic acid therapy: Adults: 48 to 70 hours; Children 5 to 11 years: 66 hours; Children 10 months to 5 years: 45 hours

Concomitant phenytoin, phenobarbital, primidone, or carbamazepine therapy: Adults: 13 to 14 hours; Children 10 months to 11 years: 7 to 8 hours

Concomitant phenytoin, phenobarbital, primidone, or carbamazepine plus valproate therapy: Adults: 27 hours; Children 5 to 11 years: 19 hours

Chronic renal failure: 43 hours

Hemodialysis: 13 hours during dialysis; 57 hours between dialysis (~20% of a dose is eliminated in a 4-hour dialysis session)

Hepatic impairment:

Mild: 26 to 66 hours

Moderate: 28 to 116 hours

Severe without ascites: 56 to 78 hours

Severe with ascites: 52 to 148 hours

Protein Binding

~55%

Special Populations: Renal Function Impairment

Plasma half-life is 43 hours in patients with chronic renal failure (CrCl of 6 to 23 mL/minute). In patients undergoing hemodialysis, half-life was 13 hours during hemodialysis and 57 hours between dialysis sessions (~20% of a dose is eliminated during a 4-hour hemodialysis session).

Special Populations: Hepatic Function Impairment

Mean half-life is 26 to 66 hours, 28 to 116 hours, 56 to 78 hours, and 52 to 14 hours in patients with mild, moderate, severe without ascites, or severe with ascites, respectively.

Special Populations: Elderly

Half-life was 25 to 43 hours and clearance was 0.3 to 0.5 mL/minute/kg.

Special Populations: Children

The oral clearance of lamotrigine was higher, on a body-weight basis, in children than in adults. Weight-normalized clearance was higher in subjects weighing <30 kg.

Special Populations: Gender

Mean trough concentrations were 24% to 45% higher in women than men.

Special Populations: Race

Oral clearance was 25% lower in nonwhite patients than in white patients.

Use: Labeled Indications

US labeling:

Bipolar I disorder (immediate release only): Maintenance treatment of bipolar I disorder to delay the time to occurrence of mood episodes (depression, mania, hypomania, mixed episodes) in patients treated for acute mood episodes with standard therapy.

Epilepsy:

Adjunctive therapy:

Immediate release: Adjunctive therapy for partial-onset seizures, generalized seizures of Lennox-Gastaut syndrome, and primary generalized tonic-clonic seizures in adults and children 2 years and older.

Extended release: Adjunctive therapy for primary generalized tonic-clonic seizures and partial-onset seizures with or without secondary generalization in patients 13 years and older.

Monotherapy:

Immediate release: Conversion to monotherapy in adults (16 years and older) with partial-onset seizures who are receiving treatment with carbamazepine, phenytoin, phenobarbital, primidone, or valproate as the single antiepileptic drug (AED).

Extended release: Conversion to monotherapy in patients 13 years and older with partial-onset seizures who are receiving treatment with a single AED.

Canadian labeling: Epilepsy: Immediate release:

Adjunctive therapy: Adjunctive therapy for epilepsy uncontrolled by conventional therapy in adults; seizures associated with Lennox-Gastaut syndrome in children ≥9 kg and adults.

Monotherapy: Monotherapy in adults with epilepsy following withdrawal of concurrent AEDs

Contraindications

Hypersensitivity (eg, rash, angioedema, acute urticaria, extensive pruritus, mucosal ulceration) to lamotrigine or any component of the formulation

Dosage

Oral: Note: Drugs that induce lamotrigine glucuronidation include carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, and atazanavir/ritonavir. Valproic acid inhibits lamotrigine glucuronidation. Extended release formulation not FDA approved for children ≤12 years of age.

US labeling:

Children 2-12 years: Lennox-Gastaut syndrome (adjunctive), partial seizures (adjunctive), or primary generalized tonic-clonic seizures (adjunctive): Note: Whole tablets should be used for dosing, round calculated dose down to the nearest whole tablet. Alternatively, a suspension may be prepared using immediate release tablets (see also Extemporaneous Prepared). Children <30 kg will likely require maintenance doses to be increased by as much as 50% based on clinical response regardless of regimen below:

Immediate release formulation:

Regimens not containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or valproic acid: Initial: Weeks 1 and 2: 0.3 mg/kg/day in 1-2 divided doses; Weeks 3 and 4: 0.6 mg/kg/day in 2 divided doses; Week 5 and beyond: Increase by 0.6 mg/kg/day every 1-2 weeks; Usual maintenance: 4.5-7.5 mg/kg/day (maximum: 300 mg daily) in 2 divided doses

Regimens containing valproic acid : Initial: Weeks 1 and 2: 0.15 mg/kg/day in 1-2 divided doses (if calculated dose is equal to or rounds down to 1 mg daily, give 2 mg every other day instead); Weeks 3 and 4: 0.3 mg/kg/day in 1-2 divided doses; Week 5 and beyond: Increase by 0.3 mg/kg/day every 1-2 weeks; Usual maintenance: 1-5 mg/kg/day (maximum: 200 mg daily) in 1 or 2 divided doses or 1 to 3 mg/kg/day with valproic acid alone (maximum: 200 mg daily)

Regimens containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, or lopinavir/ritonavir, and without valproic acid: Initial: Weeks 1 and 2: 0.6 mg/kg/day in 2 divided doses; Weeks 3 and 4: 1.2 mg/kg/day in 2 divided doses; Week 5 and beyond: Increase by 1.2 mg/kg/day every 1-2 weeks; Usual maintenance: 5-15 mg/kg/day (maximum: 400 mg daily) in 2 divided doses

Adolescents >12 years:

Lennox-Gastaut syndrome (adjunctive): Immediate release formulation: Refer to adult dosing.

Partial seizures (adjunctive) or primary generalized tonic-clonic seizures (adjunctive): Immediate release or extended release formulation: Refer to adult dosing.

Conversion from adjunctive therapy with drugs that inhibit or induce lamotrigine glucuronidation to monotherapy with lamotrigine:

Immediate release formulation: Adolescents ≥16 years: Refer to adult dosing.

Extended release formulation: Adolescents ≥13 years: Refer to adult dosing.

Adults:

Lennox-Gastaut syndrome (adjunctive): Immediate release formulation:

Regimens not containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or valproic acid: Initial: Weeks 1 and 2: 25 mg once daily; Weeks 3 and 4: 50 mg once daily; Week 5 and beyond: Increase by 50 mg daily every 1-2 weeks; Usual maintenance: 225 to 375 mg daily in 2 divided doses

Regimens containing valproic acid: Initial: Weeks 1 and 2: 25 mg every other day; Weeks 3 and 4: 25 mg once daily; Week 5 and beyond: Increase by 25 to 50 mg daily every 1 to 2 weeks; Usual maintenance: 100 to 200 mg daily (valproic acid alone) or 100 to 400 mg daily (valproic acid and other drugs that induce glucuronidation) in 1 or 2 divided doses

Regimens containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, or lopinavir/ritonavir, and without valproic acid: Initial: Weeks 1 and 2: 50 mg once daily; Weeks 3 and 4: 100 mg daily in 2 divided doses; Week 5 and beyond: Increase by 100 mg daily every 1-2 weeks; Usual maintenance: 300 to 500 mg daily in 2 divided doses (doses as high as 700 mg/day have been used)

Partial seizures (adjunctive) and primary generalized tonic-clonic seizures (adjunctive):

Immediate release formulation:

Regimens not containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or valproic acid: Initial: Weeks 1 and 2: 25 mg once daily; Weeks 3 and 4: 50 mg once daily; Week 5 and beyond: Increase by 50 mg daily every 1 to 2 weeks; Usual maintenance: 225 to 375 mg daily in 2 divided doses

Regimens containing valproic acid: Initial: Weeks 1 and 2: 25 mg every other day; Weeks 3 and 4: 25 mg once daily; Week 5 and beyond: Increase by 25-50 mg daily every 1 to 2 weeks; Usual maintenance: 100-200 mg daily (valproic acid alone) or 100 to 400 mg daily (valproic acid and other drugs that induce glucuronidation) in 1 or 2 divided doses

Regimens containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, or lopinavir/ritonavir, and without valproic acid: Initial: Weeks 1 and 2: 50 mg once daily; Weeks 3 and 4: 100 mg daily in 2 divided doses; Week 5 and beyond: Increase by 100 mg daily every 1 to 2 weeks; Usual maintenance: 300 to 500 mg daily in 2 divided doses (doses as high as 700 mg/day have been used)

Extended release formulation:

Regimens not containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or valproic acid: Initial: Weeks 1 and 2: 25 mg once daily; Weeks 3 and 4: 50 mg once daily; Week 5: 100 mg once daily; Week 6: 150 mg once daily; Week 7: 200 mg once daily; Week 8 and beyond: Dose increases should not exceed 100 mg daily at weekly intervals; Usual maintenance: 300 to 400 mg once daily

Regimens containing valproic acid: Initial: Weeks 1 and 2: 25 mg every other day; Weeks 3 and 4: 25 mg once daily; Week 5: 50 mg once daily; Week 6: 100 mg once daily; Week 7: 150 mg once daily; Week 8 and beyond: Dose increases should not exceed 100 mg daily at weekly intervals; Usual maintenance: 200 to 250 mg once daily

Regimens containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, or lopinavir/ritonavir, and without valproic acid: Initial: Weeks 1 and 2: 50 mg once daily; Weeks 3 and 4: 100 mg once daily; Week 5: 200 mg once daily; Week 6: 300 mg once daily; Week 7: 400 mg once daily; Week 8 and beyond: Dose increases should not exceed 100 mg daily at weekly intervals; Usual maintenance: 400 to 600 mg once daily

Conversion strategy from adjunctive therapy with valproic acid to monotherapy with lamotrigine:

Immediate release formulation:

- Initiate and titrate as per escalation recommendations for adjunctive therapy to a lamotrigine dose of 200 mg daily.

- Then taper valproic acid dose in decrements of not >500 mg/day/week to a valproic acid dosage of 500 mg daily; this dosage should be maintained for 1 week. The lamotrigine dosage should then be increased to 300 mg daily while valproic acid is simultaneously decreased to 250 mg daily; this dosage should be maintained for 1 week.

- Valproic acid may then be discontinued, while the lamotrigine dose is increased by 100 mg daily at weekly intervals to achieve a lamotrigine maintenance dose of 500 mg daily in 2 divided doses.

Extended release formulation:

- Initiate and titrate as per escalation recommendations for adjunctive therapy to a lamotrigine dose of 150 mg daily.

- Then taper valproic acid dose in decrements of not >500 mg/day/week to a valproic acid dose of 500 mg daily; this dosage should be maintained for 1 week. The lamotrigine dosage should then be increased to 200 mg daily while valproic acid is simultaneously decreased to 250 mg daily; this dosage should be maintained for 1 week.

- Valproic acid may then be discontinued, while the lamotrigine dose is increased to achieve a maintenance dosage range of 250-300 mg once daily.

Conversion strategy from adjunctive therapy with drugs that induce lamotrigine glucuronidation (carbamazepine, phenytoin, phenobarbital, primidone) to monotherapy with lamotrigine: Immediate release formulation and extended release formulation:

- Initiate and titrate as per escalation recommendations for adjunctive therapy to a lamotrigine dose of 500 mg daily

- Concomitant enzyme-inducing drug should then be withdrawn by 20% decrements each week over a 4-week period.

- Two weeks after withdrawal of the enzyme-inducing drug, the dosage of lamotrigine extended release may be tapered in decrements of not >100 mg/day at intervals of 1 week to achieve a maintenance dosage range of 250-300 mg once daily; no further dosage reduction is required for lamotrigine immediate release.

Conversion strategy from adjunctive therapy with drugs that do not inhibit or induce lamotrigine glucuronidation to monotherapy with lamotrigine:

Immediate release formulation: No specific guidelines available

Extended release formulation: Initiate and titrate as per escalation recommendations for adjunctive therapy to a lamotrigine dose of 250-300 mg daily. Concomitant drug should then be withdrawn by 20% decrements each week over a 4-week period.

Conversion from immediate release to extended release (Lamictal XR): Initial dose of the extended release tablet should match the total daily dose of the immediate-release formulation. Adjust dose as needed within the recommended dosing guidelines.

Bipolar I disorder (maintenance): Immediate release formulation:

Regimens not containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or valproic acid: Initial: Weeks 1 and 2: 25 mg once daily; Weeks 3 and 4: 50 mg once daily; Week 5: 100 mg once daily; Week 6 and maintenance: 200 mg once daily

Regimens containing valproic acid: Initial: Weeks 1 and 2: 25 mg every other day; Weeks 3 and 4: 25 mg once daily; Week 5: 50 mg once daily; Week 6 and maintenance: 100 mg once daily

Regimens containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, or lopinavir/ritonavir, and without valproic acid: Initial: Weeks 1 and 2: 50 mg once daily; Weeks 3 and 4: 100 mg daily in divided doses; Week 5: 200 mg daily in divided doses; Week 6: 300 mg daily in divided doses; Maintenance: Up to 400 mg daily in divided doses

Adjustment following discontinuation of drugs that inhibit or induce lamotrigine glucuronidation:

Discontinuing valproic acid with current dose of lamotrigine 100 mg daily: 150 mg daily for week 1, then increase to 200 mg daily beginning week 2

Discontinuing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, or lopinavir/ritonavir with current dose of lamotrigine 400 mg daily: 400 mg daily for week 1, then decrease to 300 mg daily for week 2, then decrease to 200 mg daily beginning week 3

Bipolar depression (acute treatment) (off-label use): Oral: Immediate release formulation: Initial: Weeks 1 and 2: 25 mg once daily; Weeks 3 and 4: 50 mg once daily; Week 5: 100 mg once daily; Week 6 and maintenance: 200 mg once daily. Doses up to 400 mg/day have been evaluated in clinical trials; however, guidelines recommend dose ranges of 50 to 200 mg/day (Geddes 2009; van der Loos 2009; WFSBP [Grunze 2010]). Note: Concurrent psychoactive drugs were excluded in clinical trials (Geddes 2009); this titration reflects product labeling recommendations for regimens not containing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or valproic acid.

Canadian labeling:

Children ≤12 years (and ≥9 kg): Lennox-Gastaut syndrome (adjunctive therapy): Note: Whole tablets should be used for dosing, round calculated dose down to the nearest whole tablet. Alternatively, a suspension may be prepared using immediate release tablets (see also Extemporaneous Prepared). Several weeks to months may be required to achieve individualized maintenance dose. Use is not recommended in children <9 kg.

Regimens containing valproic acid regardless of any other concomitant medication: Initial: Weeks 1 and 2: 0.15 mg/kg once daily (if calculated dose is equal to or rounds down to 1 mg daily give 2 mg every other day instead); Weeks 3 and 4: 0.3 mg/kg once daily; Week 5 and beyond: Increase dose by 0.3 mg/kg every 1-2 weeks (usual maintenance dose: 1-5 mg/kg daily in 1 or 2 divided doses) up to a maximum dose of 200 mg daily. Note: Alternatively, refer to manufacturer’s labeling for recommended weight-based rounding regimen.

Regimens containing carbamazepine, phenytoin, phenobarbital, primidone, or other drugs that induce glucuronidation and without valproic acid: Initial: Weeks 1 and 2: 0.3 mg/kg twice daily; Weeks 3 and 4: 0.6 mg/kg twice daily; Week 5 and beyond: Increase dose by 1.2 mg/kg every 1-2 weeks (usual maintenance dose: 2.5-7.5 mg/kg twice daily) up to a maximum dose of 400 mg daily. Note: When necessary, round doses down to closest 5 mg interval (eg, calculated dose >5 mg and <10 mg would be rounded to 5 mg; calculated dose >10 mg and <15 mg would be rounded to 10 mg). For week 5 and beyond, dose increases made every 1-2 weeks should not exceed previous daily dose administered in week 4 (eg, if week 4 dose was 20 mg daily than dose increase in week 5 or beyond should not exceed 20 mg daily). Manufacturer labeling suggests that insufficient data exists to support weight based dosing in patients >59 kg.

Adolescents >12 years: Lennox-Gastaut syndrome (adjunctive therapy): Refer to adult dosing.

Adolescents ≥16 years: Uncontrolled epilepsy (adjunctive therapy); conversion from adjunctive therapy with concomitant drugs that inhibit or induce lamotrigine glucuronidation to monotherapy with lamotrigine: Refer to adult dosing

Adults: Uncontrolled epilepsy (adjunctive) or Lennox-Gastaut syndrome (adjunctive):

Regimens containing inducers of lamotrigine glucuronidation and valproic acid or regimens not containing agents that induce or inhibit lamotrigine glucuronidation: Initial: Weeks 1 and 2: 25 mg once daily; Weeks 3 and 4: 25 mg twice daily; Week 5 and beyond: Increase dose by 25-50 mg every 1-2 weeks until maintenance dose established (usual maintenance dose: 100-200 mg daily in 2 divided doses)

Alternatively, a more cautious titration schedule for regimens containing valproic acid (regardless of any concomitant medication): Initial: Weeks 1 and 2: 25 mg every other day; Weeks 3 and 4: 25 mg once daily; Week 5 and beyond: Increase dose by 25-50 mg every 1-2 weeks until maintenance dose established (usual maintenance dose: 100-200 mg daily in 2 divided doses).

Regimens containing inducers of lamotrigine glucuronidation and without valproic acid: Initial: Weeks 1 and 2: 50 mg once daily; Weeks 3 and 4: 50 mg twice daily; Week 5 and beyond: Increase dose by 100 mg every 1-2 weeks until maintenance dose established (usual maintenance dose: 300-500 mg daily in 2 divided doses)

Conversion from adjunctive therapy with concomitant drugs that inhibit or induce lamotrigine glucuronidation to lamotrigine monotherapy: Decrease dose of concomitant antiepileptic agent by ~20% of original dose every week for 5 weeks (slower taper may be considered if clinically indicated). Lamotrigine dosage adjustments during this period should be determined by changes in lamotrigine pharmacokinetics due to withdrawal of the concomitant drugs that inhibit or induce lamotrigine glucuronidation, and by the clinical response of patient.

Additional considerations:

Discontinuing therapy: Decrease dose by ~50% per week, over at least 2 weeks unless safety concerns require a more rapid withdrawal. Discontinuing carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or atazanavir/ritonavir should prolong the half-life of lamotrigine; discontinuing valproic acid should shorten the half-life of lamotrigine

Restarting therapy after discontinuation: If lamotrigine has been withheld for >5 half-lives, consider restarting according to initial dosing recommendations. Note: Concomitant medications may affect the half-life of lamotrigine; consider pharmacokinetic interactions when restarting therapy.

Concomitant therapy:

Dosage adjustment with atazanavir/ritonavir: Follow initial lamotrigine dosing guidelines, maintenance dose should be adjusted as follows:

Patients not taking concomitant carbamazepine, phenytoin, phenobarbital, primidone, rifampin, estrogen-containing contraceptives, or lopinavir/ritonavir: Lamotrigine maintenance dose may need to be increased if atazanavir/ritonavir is added or decreased if atazanavir/ritonavir is discontinued.

Dosage adjustment with estrogen-containing hormonal contraceptives: Follow initial lamotrigine dosing guidelines, maintenance dose should be adjusted as follows, based on concomitant medications:

Patients taking concomitant carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or atazanavir/ritonavir: No dosing adjustment required

Patients not taking concomitant carbamazepine, phenytoin, phenobarbital, primidone, rifampin, lopinavir/ritonavir, or atazanavir/ritonavir: Lamotrigine maintenance dose may need increased by twofold over target dose. If already taking a stable dose of lamotrigine and starting contraceptive, maintenance dose may need increased by twofold. Dose increases should start when contraceptive is started and titrated to clinical response increasing no more rapidly than 50-100 mg daily every week. Gradual increases of lamotrigine plasma levels may occur during the inactive “pill-free” week and will be greater when dose increases are made the week before. If increased adverse events consistently occur during “pill-free” week, overall maintenance dose adjustments may be required. When discontinuing estrogen-containing hormonal contraceptive, dose of lamotrigine may need decreased by as much as 50%; do not decrease by more than 25% of total daily dose over a 2-week period unless clinical response or plasma levels indicate otherwise. Dose adjustments during “pill-free” week are not recommended.

Dosage adjustment in renal impairment: There are no dosage adjustments provided in the manufacturer’s labeling. Decreased maintenance dosage may be effective in patients with significant renal impairment; has not been adequately studied; use with caution

Dosage adjustment in hepatic impairment:

US labeling:

Mild impairment: No dosage adjustment necessary.

Moderate-to-severe impairment without ascites: Decrease initial, escalation, and maintenance doses by ~25%; adjust according to clinical response and tolerance.

Moderate-to-severe impairment with ascites: Decrease initial, escalation, and maintenance doses by ~50%; adjust according to clinical response and tolerance.

Canadian labeling:

Mild and moderate impairment (Child-Pugh classes A and B): Reduce initial, escalation, and maintenance dosing by ~50%; adjust according to clinical response and tolerance.

Severe impairment (Child-Pugh class C): Reduce initial, escalation, and maintenance dosing by ~75%; adjust according to clinical response and tolerance.

Extemporaneously Prepared

A 1 mg/mL oral suspension may be made with tablets and one of two different vehicles (a 1:1 mixture of Ora-Sweet and Ora-Plus or a 1:1 mixture of Ora-Sweet SF and Ora-Plus). Crush one 100 mg tablet in a mortar and reduce to a fine powder. Add small portions of the chosen vehicle and mix to a uniform paste; mix while adding the vehicle in incremental proportions to almost 100 mL; transfer to a graduated cylinder, rinse mortar with vehicle, and add quantity of vehicle sufficient to make 100 mL. Label "shake well" and "protect from light". Stable for 91 days when stored in amber plastic prescription bottles in the dark at room temperature or refrigerated.

Nahata M, Morosco R, Hipple T. “Stability of Lamotrigine in Two Extemporaneously Prepared Oral Suspensions at 4 and 25 Degrees C,” Am J Health Syst Pharm, 1999, 56(3):240-2.10030509

Administration

Doses should be rounded down to the nearest whole tablet.

Lamictal chewable/dispersible tablets: May be chewed, dispersed in water or diluted fruit juice, or swallowed whole. To disperse tablets, add to a small amount of liquid (just enough to cover tablet); let sit ~1 minute until dispersed; swirl solution and consume immediately. Do not administer partial amounts of liquid. If tablets are chewed, a small amount of water or diluted fruit juice should be used to aid in swallowing.

Lamictal ODT: Place tablets on tongue and move around in the mouth. Tablets will dissolve rapidly and can be swallowed with or without food or water.

Lamictal XR: Administer without regard to meals. Swallow whole; do not chew, crush, or cut.

Storage

Store at 15°C to 30°C (59°F to 86°F). Protect from light.

Drug Interactions

Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Monitor therapy

Atazanavir: May decrease the serum concentration of LamoTRIgine. Monitor therapy

Azelastine (Nasal): CNS Depressants may enhance the CNS depressant effect of Azelastine (Nasal). Avoid combination

Barbiturates: May decrease the serum concentration of LamoTRIgine. Management: See lamotrigine prescribing information for specific age-dependent dosing guidelines regarding concurrent use with a barbiturate, as well as for adjusting lamotrigine dosing if concurrent barbiturate therapy is discontinued. Consider therapy modification

Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Buprenorphine: CNS Depressants may enhance the CNS depressant effect of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine patches (Butrans brand) at 5 mcg/hr in adults when used with other CNS depressants. Consider therapy modification

Cannabis: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

CarBAMazepine: LamoTRIgine may enhance the adverse/toxic effect of CarBAMazepine. CarBAMazepine may increase the metabolism of LamoTRIgine. Consider therapy modification

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Exceptions: Levocabastine (Nasal). Monitor therapy

Contraceptives (Estrogens): May decrease the serum concentration of LamoTRIgine. Management: Monitor for increased serum concentrations/effects of lamotrigine in patients in whom a hormonal contraceptive is discontinued/dose decreased (this includes during a pill-free week). A reduced dosage of lamotrigine may be needed. Consider therapy modification

Contraceptives (Progestins): LamoTRIgine may decrease the serum concentration of Contraceptives (Progestins). Management: Women using progestin-only “minipill” products may be at risk for contraceptive failure; it is unclear if other progestin-containing products would be significantly impacted. Alternative, non-hormonal, means of contraception are recommended. Consider therapy modification

Desmopressin: LamoTRIgine may enhance the adverse/toxic effect of Desmopressin. Monitor therapy

Dofetilide: LamoTRIgine may increase the serum concentration of Dofetilide. Avoid combination

Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. Monitor therapy

Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (e.g., opioids, barbiturates) with concomitant use. Consider therapy modification

Ezogabine: May decrease the serum concentration of LamoTRIgine. Monitor therapy

Fosphenytoin: May decrease the serum concentration of LamoTRIgine. Consider therapy modification

Hydrocodone: CNS Depressants may enhance the CNS depressant effect of Hydrocodone. Management: Consider starting with a 20% to 30% lower hydrocodone dose when using together with any other CNS depressant. Dose reductions in the other CNS depressant may also be warranted. Consider therapy modification

HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Mefloquine: May diminish the therapeutic effect of Anticonvulsants. Mefloquine may decrease the serum concentration of Anticonvulsants. Management: Mefloquine is contraindicated for malaria prophylaxis in persons with a history of convulsions. Monitor anticonvulsant concentrations and treatment response closely with concurrent use. Consider therapy modification

MetFORMIN: LamoTRIgine may increase the serum concentration of MetFORMIN. Management: The lamotrigine Canadian product monograph states that coadministration of these drugs is not recommended. Monitor therapy

Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce adult dose of CNS depressant agents by 50% with initiation of concomitant methotrimeprazine therapy. Further CNS depressant dosage adjustments should be initiated only after clinically effective methotrimeprazine dose is established. Consider therapy modification

Metyrosine: CNS Depressants may enhance the sedative effect of Metyrosine. Monitor therapy

Mianserin: May diminish the therapeutic effect of Anticonvulsants. Monitor therapy

Minocycline: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Mirtazapine: CNS Depressants may enhance the CNS depressant effect of Mirtazapine. Monitor therapy

Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

OLANZapine: LamoTRIgine may enhance the sedative effect of OLANZapine. Monitor therapy

Orlistat: May decrease the serum concentration of Anticonvulsants. Monitor therapy

Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination

Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination

Perampanel: May enhance the CNS depressant effect of CNS Depressants. Management: Patients taking perampanel with any other drug that has CNS depressant activities should avoid complex and high-risk activities, particularly those such as driving that require alertness and coordination, until they have experience using the combination. Consider therapy modification

Phenytoin: May decrease the serum concentration of LamoTRIgine. Consider therapy modification

Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy

Primidone: May decrease the serum concentration of LamoTRIgine. Management: Adjust dose per lamotrigine prescribing information guidelines during primidone treatment. Monitor for decreased concentration/effect if primidone is initiated/dose increased or increased concentration/effect if primidone is discontinued/dose decreased. Consider therapy modification

Procainamide: LamoTRIgine may increase the serum concentration of Procainamide. Management: Consider monitoring for increased procainamide concentrations and/or systemic effects in patients receiving procainamide with lamotrigine. The lamotrigine Canadian product monograph states that coadministration of these agents is not recommended. Monitor therapy

Rifampin: May increase the metabolism of LamoTRIgine. Monitor therapy

Ritonavir: May decrease the serum concentration of LamoTRIgine. Consider therapy modification

ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy

Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy

Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy

Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors. Specifically, the risk of psychomotor impairment may be enhanced. Monitor therapy

Sodium Oxybate: May enhance the CNS depressant effect of CNS Depressants. Management: Consider alternatives to combined use. When combined use is needed, consider minimizing doses of one or more drugs. Use of sodium oxybate with alcohol or sedative hypnotics is contraindicated. Consider therapy modification

Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Consider therapy modification

Tapentadol: May enhance the CNS depressant effect of CNS Depressants. Management: Start tapentadol at a dose of one-third to one-half of the normal dose if being initiated in a patient who is taking another drug with CNS depressant effects. Monitor closely for evidence of excessive CNS depression. Consider therapy modification

Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination

Valproate Products: May enhance the adverse/toxic effect of LamoTRIgine. Valproate Products may increase the serum concentration of LamoTRIgine. Consider therapy modification

Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Consider therapy modification

Test Interactions

May interfere with some rapid urine drug screens, particularly phencyclidine (false-positives).

Adverse Reactions

Percentages reported in adults on monotherapy for epilepsy or bipolar disorder.

>10%: Gastrointestinal: Nausea (7% to 14%)

1% to 10%:

Cardiovascular: Chest pain (5%), peripheral edema (2% to 5%), edema (1% to 5%)

Central nervous system: Insomnia (5% to 10%), drowsiness (9%), fatigue (8%), dizziness (7%), ataxia (2% to 7%), anxiety (5%), pain (5%), irritability (2% to 5%), suicidal ideation (2% to 5%), abnormal dreams (1% to 5%), abnormality in thinking (1% to 5%), agitation (1% to 5%), amnesia (1% to 5%), depression (1% to 5%), dyspraxia (1% to 5%), emotional lability (1% to 5%), hypoesthesia (1% to 5%), migraine (1% to 5%), hyperreflexia (>2% to <5%), hyporeflexia (>2% to <5%), confusion (1%), paresthesia (≥1%)

Dermatologic: Skin rash (nonserious 7%; requiring hospitalization ≤1%), dermatitis (2% to 5%), diaphoresis (2% to 5%), xeroderma (2% to 5%)

Endocrine & metabolic: Dysmenorrhea (5% to 7%), weight loss (5%), weight gain (1% to 5%)

Gastrointestinal: Vomiting (5% to 9%), dyspepsia (7%), abdominal pain (6%), xerostomia (2% to 6%), constipation (5%), anorexia (2% to 5%), peptic ulcer (2% to 5%), flatulence (1% to 5%),

Genitourinary: Increased libido (2% to 5%), urinary frequency (1% to 5%)

Hematologic & oncologic: Rectal hemorrhage (2% to 5%)

Infection: Infection (5%)

Neuromuscular & skeletal: Back pain (8%), weakness (2% to 5%), arthralgia (1% to 5%), myalgia (1% to 5%), neck pain (1% to 5%)

Ophthalmic: Nystagmus (2% to 5%), visual disturbance (2% to 5%), amblyopia (≥1%)

Respiratory: Rhinitis (7%), cough (5%), pharyngitis (5%), bronchitis (2% to 5%), dyspnea (2% to 5%), epistaxis (2% to 5%), sinusitis (1% to 5%), nasopharyngitis (≥3%), upper respiratory tract infection (≥3%)

Miscellaneous: Fever (1% to 5%)

<1% (Limited to important or life-threatening): Abnormal hepatic function tests, abnormal lacrimation, accommodation disturbance, acne vulgaris, acute renal failure, ageusia, agranulocytosis, akathisia, alcohol intolerance, alopecia, altered sense of smell, amyotrophy, anemia, anorgasmia, apathy, aphasia, apnea, arthritis, aseptic meningitis, blepharoptosis, breast abscess, breast neoplasm, bursitis, central nervous system depression, cerebellar syndrome, conjunctivitis, cystitis, deafness, decreased fibrin, decreased libido, decreased serum fibrinogen, deep vein thrombophlebitis, delirium, delusions, depersonalization, depression, dermatitis (exfoliative, fungal), disseminated intravascular coagulation, DRESS syndrome, dry eye syndrome, dysphagia, dysphoria, dysuria, ecchymosis, ejaculatory disorder, eosinophilia, epididymitis, eructation, erythema multiforme, esophagitis, exacerbation of Parkinson disease, extrapyramidal reaction, gastritis, gastrointestinal hemorrhage, gingival hemorrhage, gingival hyperplasia, gingivitis, glossitis, hallucination, hemiplegia, hemorrhage, hepatitis, hepatotoxicity (idiosyncratic) (Chalasani, 2014), herpes zoster, hirsutism, hostility, hot flash, hyperalgesia, hyperbilirubinemia, hyperesthesia, hyperglycemia, hypermenorrhagia, hypersensitivity reaction, hypertension, hyperventilation, hypokinesia, hypothyroidism, hypotonia, immunosuppression (progressive), impotence, increased appetite, increased gamma glutamyl transpeptidase, increased serum alkaline phosphatase, increased serum ALT, increased serum AST, lactation, leg cramps, leukocytosis, leukoderma, leukopenia, lupus-like syndrome, lymphadenopathy, lymphocytosis, maculopapular rash, malaise, manic depressive reaction, memory impairment, multiorgan failure, muscle spasm, myasthenia, myoclonus, neuralgia, neutropenia, nightmares, oral mucosa ulcer, orthostatic hypotension, oscillopsia, otalgia, palpitations, pancreatitis, pancytopenia, panic attack, paralysis, paranoid reaction, pathological fracture, peripheral neuritis, personality disorder, petechia, photophobia, polyuria, psychosis, pure red cell aplasia, pustular rash, racing mind, renal pain, rhabdomyolysis, sialorrhea, skin discoloration, sleep disorder, status epilepticus, Stevens-Johnson syndrome, strabismus, suicidal tendencies, syncope, tachycardia, tendinous contracture, thrombocytopenia, tics, tinnitus, tonic-clonic seizures (exacerbation), urinary incontinence, urinary retention, urinary urgency, uveitis, vasculitis, vasodilation, vesiculobullous dermatitis, visual field defect, withdrawal seizures

ALERT: U.S. Boxed Warning

Serious skin rashes:

Lamotrigine can cause serious rashes requiring hospitalization and discontinuation of treatment. The incidence of these rashes, which have included Stevens-Johnson syndrome, is approximately 0.3% to 0.8% in pediatric patients (2 to 17 years of age) and 0.08% to 0.3% in adults receiving lamotrigine. One rash-related death was reported in a prospectively followed cohort of 1,983 pediatric patients (2 to 16 years of age) with epilepsy taking lamotrigine immediate-release as adjunctive therapy. In worldwide postmarketing experience, rare cases of toxic epidermal necrolysis and/or rash-related death have been reported in adults and pediatric patients, but those numbers are too few to permit a precise estimate of the rate.

The risk of serious rash caused by treatment with lamotrigine ER is not expected to differ from that with the immediate-release formulation of lamotrigine. However, the relatively limited treatment experience with lamotrigine ER makes it difficult to characterize the frequency and risk of serious rashes caused by treatment with lamotrigine ER. Lamotrigine ER is not approved for patients younger than 13 years.

Other than age, there are as yet no factors identified that are known to predict the risk of occurrence or the severity of rash caused by lamotrigine. There are suggestions, yet to be proven, that the risk of rash may also be increased by coadministration of lamotrigine with valproate (includes valproic acid and divalproex sodium), exceeding the recommended initial dose of lamotrigine, or exceeding the recommended dose escalation for lamotrigine. However, cases have been reported in the absence of these factors.

Nearly all cases of life-threatening rashes associated with lamotrigine have occurred within 2 to 8 weeks of treatment initiation. However, isolated cases have been reported after prolonged treatment (eg, 6 months). Accordingly, duration of therapy cannot be relied upon as a means to predict the potential risk heralded by the first appearance of a rash.

Although benign rashes are also caused by lamotrigine, it is not possible to predict reliably which rashes will prove to be serious or life-threatening. Accordingly, lamotrigine should ordinarily be discontinued at the first sign of rash unless the rash is clearly not drug-related. Discontinuation of treatment may not prevent a rash from becoming life-threatening or permanently disabling or disfiguring.

Warnings/Precautions

Concerns related to adverse effects:

• Aseptic meningitis: Increased risk of developing aseptic meningitis has been reported; symptoms (eg, headache, nuchal rigidity, fever, nausea/vomiting, rash, photophobia) have generally occurred within 1 to 45 days following therapy initiation. In some cases, new onset hepatic, renal and/or other organ involvement has also occurred with symptoms, possibly suggesting aseptic meningitis is associated with a hypersensitivity reaction (eg, anticonvulsant hypersensitivity syndrome). Symptoms of aseptic meningitis generally resolve following discontinuation. In some cases, re-exposure has resulted in a rapid return of symptoms (often more severe).

• Blood dyscrasias: A spectrum of hematologic effects have been reported with use (eg, neutropenia, leukopenia, thrombocytopenia, pancytopenia, anemias, and rarely, aplastic anemia and pure red cell aplasia); patients with a previous history of adverse hematologic reaction to any drug may be at increased risk. Early detection of hematologic change is important; advise patients of early signs and symptoms including fever, sore throat, mouth ulcers, infections, easy bruising, petechial or purpuric hemorrhage. May be associated with hypersensitivity syndrome.

• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

• Multiorgan hypersensitivity reactions (drug reaction with eosinophilia and systemic symptoms [DRESS]): Potentially serious, sometimes fatal, multiorgan hypersensitivity reactions (DRESS) have been reported with some antiepileptic drugs (rare). Symptoms may include fever, rash, and/or lymphadenopathy; monitor for signs and symptoms of possible disparate manifestations associated with lymphatic, hepatic, renal, and/or hematologic organ systems. Early symptoms of hypersensitivity reaction (eg, lymphadenopathy, fever) may occur without rash; discontinuation and conversion to alternate therapy may be required.

• Skin reactions: [US Boxed Warning]: Serious skin rashes requiring hospitalization and discontinuation of treatment have been reported; incidence of serious rash is higher in pediatric patients than adults; risk may be increased by coadministration with valproic acid, higher than recommended initial doses, exceeding recommended initial dose titration, or exceeding the recommended dose escalation for lamotrigine. One rash-related death was reported in a pediatric patients taking lamotrigine immediate-release as adjunctive therapy. Nearly all cases of life-threatening rashes associated with lamotrigine have occurred within 2 to 8 weeks of treatment initiation; however, isolated cases may occur after prolonged treatment (eg, 6 months) or in patients without these risk factors; discontinue at first sign of rash and do not reinitiate therapy unless rash is clearly not drug related. Rare cases of toxic epidermal necrolysis and/or rash-related death have been reported. Discontinuation of treatment may not prevent a rash from becoming life-threatening or permanently disabling or disfiguring.

• Suicidal ideation: Pooled analysis of trials involving various antiepileptics (regardless of indication) showed an increased risk of suicidal thoughts/behavior (incidence rate: 0.43% treated patients compared to 0.24% of patients receiving placebo); risk observed as early as 1 week after initiation and continued through duration of trials (most trials ≤24 weeks). Monitor all patients for notable changes in behavior that might indicate suicidal thoughts or depression; notify healthcare provider immediately if symptoms occur.

Disease-related concerns:

• Hepatic impairment: Use with caution in patients with hepatic impairment; dosage adjustment may be required.

• Renal impairment: Use with caution in patients with renal impairment; dosage adjustment may be required.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Pediatric: Children are at increased risk for developing serious skin rashes during therapy; lower starting doses and slower dose escalations may decrease the risk of rash.

Dosage form specific issues:

• Polysorbate 80: Some dosage forms may contain polysorbate 80 (also known as Tweens). Hypersensitivity reactions, usually a delayed reaction, have been reported following exposure to pharmaceutical products containing polysorbate 80 in certain individuals (Isaksson, 2002; Lucente 2000; Shelley, 1995). Thrombocytopenia, ascites, pulmonary deterioration, and renal and hepatic failure have been reported in premature neonates after receiving parenteral products containing polysorbate 80 (Alade, 1986; CDC, 1984). See manufacturer’s labeling.

Other warnings/precautions:

• Appropriate use: Bipolar disorder use: Patients treated for bipolar disorder should be monitored closely for clinical worsening or suicidality; reassess patients to determine the need for maintenance treatment if on therapy >16 weeks. Prescriptions should be written for the smallest quantity consistent with good patient care. Treatment of acute manic or mixed episodes is not recommended; efficacy has not been established and slow titration limits use.

• Medication error potential: Medication errors have occurred; potential for medication errors with similar-sounding medications and between different lamotrigine formulations.

• Melanin binding: Binds to melanin and may accumulate in the eye and other melanin-rich tissues; the clinical significance of this is not known.

• Monotherapy: Epilepsy: Safety and efficacy have not been established for use as initial monotherapy, conversion to monotherapy from antiepileptic drugs (AED) other than carbamazepine, phenytoin, phenobarbital, primidone or valproic acid or conversion to monotherapy from two or more AEDs.

• Withdrawal: Anticonvulsants should not be discontinued abruptly because of the possibility of increasing seizure frequency; therapy should be withdrawn gradually to minimize the potential of increased seizure frequency, unless safety concerns require a more rapid withdrawal. Taper over at least 2 weeks if possible.

Monitoring Parameters

Serum levels of concurrent anticonvulsants, LFTs, renal function, hypersensitivity reactions (especially rash); seizure, frequency and duration; suicidality (eg, suicidal thoughts, depression, behavioral changes); signs/symptoms of aseptic meningitis

Pregnancy Risk Factor

C

Pregnancy Considerations

Adverse events have been observed in animal reproduction studies. Lamotrigine crosses the human placenta and can be measured in the plasma of exposed newborns (Harden and Pennell, 2009; Ohman, 2000). An overall increase in major congenital malformations has not been observed in available studies; however, an increased risk for cleft lip or cleft palate has not been ruled out (Cunnington, 2011; Hernández-Díaz, 2012; Holmes, 2012). An increased risk of malformations following maternal lamotrigine use may be associated with larger doses (Cunnington, 2007; Tomson, 2011). Polytherapy may increase the risk of congenital malformations; monotherapy with the lowest effective dose is recommended (Harden and Meader, 2009).

Due to pregnancy-induced physiologic changes, women who are pregnant may require dose adjustments of lamotrigine in order to maintain clinical response; monitoring during pregnancy should be considered (Harden and Pennell, 2009). For women with epilepsy who are planning a pregnancy in advance, baseline serum concentrations should be measured once or twice prior to pregnancy during a period when seizure control is optimal. Monitoring can then be continued up to once a month during pregnancy and every second day during the first week postpartum (Patsalos, 2008). In women taking lamotrigine who are trying to avoid pregnancy, potentially significant interactions may exist with hormone-containing contraceptives; consult drug interactions database for more detailed information.

Pregnancy registries are available for women who have been exposed to lamotrigine. Patients may enroll themselves in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling (888) 233-2334. Additional information is available at www.aedpregnancyregistry.org.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience fatigue, headache, nausea, tremors, insomnia, rhinorrhea, diarrhea, or dyspepsia. Have patient report immediately to prescriber signs of infection, signs of hepatic impairment, signs of renal impairment, dyspnea, excessive weight gain, edema of extremities, enlarged lymph nodes, considerable asthenia, significant myalgia, intolerable arthralgia, considerable joint edema, ecchymosis, hemorrhaging, vision changes, severe dizziness, syncope, change in balance, involuntary eye movements, angina, flu-like symptoms, suicidal ideation, depression, anxiety, akathisia, irritability, panic attacks, mood changes, or signs of aseptic meningitis (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

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