Modafinil
Pronouncation: (moe-DAFF-ih-nill)Class: Analeptic
Trade Names:
Provigil
- Tablets 100 mg
- Tablets 200 mg
Pharmacology
Feedback for Modafinil
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Wakefulness-promoting agent; however, precise mechanism(s) unknown.
Pharmacokinetics
Absorption
T max is 2 to 4 h. Food delays T max approximately 1 h.
Distribution
Apparent Vd is 0.9 L/kg and protein binding is approximately 60%.
Metabolism
Primary site is hepatic via hydrolytic deamination, S-oxidation, aromatic ring hydroxylation, and glucuronide conjugation. Major inactive metabolites are modafinil acid and modafinil sulfone. Modafinil induces it own metabolism via CYP-450 3A4 after chronic administration.
Elimination
Approximately 80% (urine) and 1% (feces) are excreted in 11 days. The t ½ is approximately 15 h.
Special Populations
Hepatic Function ImpairmentIn severe hepatic function impairment, Cl is decreased approximately 60%, and steady-state concentrations are doubled. Dose reduction is recommended.
Indications and Usage
Improve wakefulness in patients with excessive daytime sleepiness associated with narcolepsy, obstructive sleep apnea/hypopnea syndrome (OSAHS), and shift work sleep disorder (SWSD).
Unlabeled Uses
Treatment of fatigue associated with multiple sclerosis.
Contraindications
Standard considerations.
Dosage and Administration
Adults and Children (16 yr of age and older)PO 200 mg/day as a single dose. Patients with narcolepsy or OSAHS should take dose in the morning, while patients with SWSD should take dose 1 h prior to start of work shift. Dosage adjustment should be considered for concomitant medications that are substrates for CYP3A4, such as triazolam and cyclosporine.
ElderlyConsider using a lower dose in this population.
Hepatic function impairmentA dose reduction of 50% is recommended.
Storage/Stability
Store tablets at controlled room temperature (68° to 77°F).
Drug Interactions
Certain tricyclic antidepressants (eg, clomipramine, desipramine)Plasma levels of certain tricyclic antidepressants may be increased.
ClomipraminePlasma levels may be increased by modafinil.
Contraceptives, oralEfficacy may be decreased by modafinil, increasing the risk of unintended pregnancy.
CyclosporineBlood levels may be decreased by modafinil.
MAOIs (eg, isocarboxazid)Use with caution.
MethylphenidateMay delay the absorption of modafinil.
PhenytoinIncreased risk of phenytoin toxicity.
TriazolamTriazolam concentration may be decreased, reducing the clinical effect.
WarfarinMonitor PT.
Laboratory Test Interactions
None well documented.
Adverse Reactions
Cardiovascular
Hypertension (3%); palpitation, tachycardia, vasodilatation (2%).
CNS
Headache (34%); nervousness (7%); anxiety, dizziness, insomnia (5%); depression, emotional lability, paresthesia, somnolence (2%); anxiety, confusion, dyskinesia, hyperkinesias, hypertonia, tremor, vertigo (1%); symptoms of mania or psychosis (postmarketing).
Dermatologic
Sweating, herpes simplex (1%).
EENT
Rhinitis (7%); pharyngitis (4%); abnormal vision, amblyopia, epistaxis, eye pain (1%).
GI
Nausea (11%); diarrhea (6%); dyspepsia (5%); anorexia, dry mouth (4%); constipation (2%); flatulence, mouth ulceration, thirst, (1%); taste perversion (1%).
Genitourinary
Hematuria, pyuria, urine abnormality (1%).
Hematologic-Lymphatic
Eosinophilia (1%); agranulocytosis (postmarketing).
Hepatic
Abnormal liver function (2%).
Lab Tests
Increased gamma glutamyltransferase and alkaline phosphatase.
Metabolic-Nutritional
Edema (1%).
Musculoskeletal
Back pain (6%); neck pain (1%).
Respiratory
Lung disorder (2%); asthma (1%).
Miscellaneous
Flu-like syndrome (4%); chest pain (3%); chills (1%).
Precautions
Pregnancy
Category C .
Lactation
Undetermined.
Children
Safety and efficacy in children younger than 16 yr of age not established.
Hepatic Function
Dosage reduction is recommended in patients with severe hepatic function impairment.
CNS
Psychotic episodes have been reported.
CV system
Not recommended for use in patients with history of left ventricular hypertrophy or mitral valve prolapse who have experienced mitral valve prolapse syndrome when receiving CNS stimulants.
Drug dependence
Because of psychoactive and euphoric effects, modafinil has potential for abuse.
MI/Unstable angina
Use with caution.
Wakefulness
May not return to normal in patients taking modafinil.
Overdosage
Symptoms
Excitation, agitation, insomnia, slight to moderate elevations in hemodynamic parameters, anxiety, irritability, aggressiveness, confusion, nervousness, tremor, palpitations, sleep disturbances, nausea, diarrhea, decreased PT.
Patient Information
- Advise patient that medication will not cure sleep disorder and is not a replacement for sleep.
- Advise patient to read patient information leaflet before beginning therapy and to reread it each time medication is renewed.
- Advise patient that medication is taken only once a day.
- Advise patient using modafinil for narcolepsy or OSAHS to take prescribed dose in the morning to minimize sleep disturbances.
- Advise patient using modafinil for SWSD to take prescribed dose 1 h prior to start of shift work.
- Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
- Advise patient to continue to take previously prescribed treatments (eg, CPAP for patient with OSAHS) as instructed by health care provider.
- Caution patients not to alter previous behavior with regard to potentially dangerous activities (eg, driving, operating machinery) or other activities requiring appropriate levels of wakefulness until, and unless, treatment with modafinil has been shown to produce levels of wakefulness that permit such activities.
- Advise patient to take medication as prescribed and to not stop taking or change the dose unless advised by health care provider.
- Caution patient that drug may alter judgment, thinking, or motor skills and to use caution while driving or performing other tasks requiring mental alertness and coordination until tolerance is determined.
- Caution patient that the use of modafinil in combination with alcohol has not been studied, and it is prudent to avoid alcohol while taking modafinil.
- Advise patient to notify health care provider if appetite loss, nervousness, difficulty sleeping, or other bothersome adverse reactions occur.
- Advise patient to stop taking modafinil and immediately notify health care provider if chest pain, mental problems, or rash, hives, or other symptoms of an allergic reaction occur.
- Advise women using hormonal contraception (oral, depot, or implantable) to use alternative or concomitant methods of contraception with, and for 1 mo following discontinuation of, therapy.
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More Modafinil resources:
Modafinil - Includes detailed dosage instructions.
Multiple Sclerosis, Obstructive Sleep Apnea/Hypopnea Syndrome, Narcolepsy, Shift Work Sleep Disorder














