Amitriptyline Dosage

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Usual Adult Dose for:

Usual Geriatric Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Depression

Oral:
Initial dose: 25 to 100 mg per day in 3 to 4 divided doses or 50 to 100 mg at bedtime.
Maintenance dose: 25 to 150 mg per day in single or 3 to 4 divided doses. 25 mg per day at bedtime has been used for premenstrual depression. Dose increases should be made gradually. A small number of hospitalized patients may need as much as 300 mg per day. ECG, blood pressure, and heart rate monitoring is recommended for patients receiving high doses.

IM:
20 to 30 mg up to 4 times a day. Patients should be switched to oral therapy as soon as possible.

Usual Adult Dose for Migraine Prophylaxis

10 mg orally once a day at bedtime.

Usual Adult Dose for Dysthymia

Oral:
Initial dose: 75 mg per day orally in single or divided doses.
Maintenance dose: 150 to 300 mg per day orally in single or divided doses. Dose increases should be made gradually. ECG, blood pressure, and heart rate monitoring is recommended for patients receiving high doses.

IM:
20 to 30 mg up to 4 times a day. Patients should be switched to oral therapy as soon as possible.

Usual Adult Dose for Pain

Oral:
Initial dose: 75 mg per day orally in single or divided doses.
Maintenance dose: 150 to 300 mg per day orally in single or divided doses. Dose increases should be made gradually. ECG, blood pressure, and heart rate monitoring is recommended for patients receiving high doses.

IM:
20 to 30 mg up to 4 times a day. Patients should be switched to oral therapy as soon as possible.

Usual Adult Dose for Post Traumatic Stress Disorder

Oral:
Initial dose: 75 mg per day orally in single or divided doses.
Maintenance dose: 150 to 300 mg per day orally in single or divided doses. Dose increases should be made gradually. ECG, blood pressure, and heart rate monitoring is recommended for patients receiving high doses.

IM:
20 to 30 mg up to 4 times a day. Patients should be switched to oral therapy as soon as possible.

Usual Adult Dose for Somatoform Pain Disorder

Oral:
Initial dose: 75 mg per day orally in single or divided doses.
Maintenance dose: 150 to 300 mg per day orally in single or divided doses. Dose increases should be made gradually. ECG, blood pressure, and heart rate monitoring is recommended for patients receiving high doses.

IM:
20 to 30 mg up to 4 times a day. Patients should be switched to oral therapy as soon as possible.

Usual Geriatric Dose for Depression

Oral:
10 mg orally 3 times a day and 20 mg at bedtime may be satisfactory in patients who do not tolerate higher dosages. Any dose increases should be made gradually.

IM:
20 to 30 mg up to 4 times a day. Patients should be switched to oral therapy as soon as possible.

Usual Pediatric Dose for Depression

9 to 12 years:
Initial dose: 1 mg/kg/day orally in 3 divided doses
Maintenance dose: 1 to 5 mg/kg/day in 3 divided doses. Dose increases should be made gradually. ECG, heart rate, and blood pressure monitoring is recommended when doses exceed 3 mg/kg/day.

12 to 18 years:
Oral:
Initial dose: 25 to 50 mg per day orally in single or 3 to 4 divided doses.
Maintenance dose: 20 to 200 mg per day in divided doses. Dose increases should be made gradually. 10 mg orally 3 times a day and 20 mg at bedtime may be satisfactory in patients who do not tolerate higher dosages.

IM:
20 to 30 mg up to 4 times a day. Patients should be switched to oral therapy as soon as possible.

Usual Pediatric Dose for Pain

1 to 12 years:
Initial dose: 0.1 mg/kg orally at bedtime (investigational).
Maintenance dose: May increase as tolerated over 2 to 3 weeks to 0.5 to 2 mg/kg at bedtime.

12 to 18 years:
Initial dose: 25 mg twice daily.
Maintenance dose: 50 to 200 mg per day in divided doses. Dose increases should be made gradually.

Usual Pediatric Dose for Migraine Prophylaxis

6 to 12 years: 0.25 to 1.5 mg/kg/day once daily at bedtime (investigational). Dose increases should be made gradually.

12 to 18 years:
Initial dose: 25 mg twice daily.
Maintenance dose: 50 to 200 mg per day in divided doses. Dose increases should be made gradually.

Usual Pediatric Dose for Urinary Incontinence

2 to 6 years: 10 mg orally at bedtime has been tried for nocturnal enuresis (investigational).

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Use with caution in patients with hepatic impairment.

Dose Adjustments

The total daily dosage may be given in a single dose preferably at bedtime. When satisfactory improvement has been reached, dosage should be reduced to the lowest amount that will maintain relief of symptoms. It is appropriate to continue maintenance therapy 3 months or longer to lessen the possibility of relapse.

Precautions

The concurrent use of amitriptyline and MAO inhibitors is contraindicated. At least 14 days should elapse between discontinuation of amitriptyline and initiation of an MAO inhibitor, or vice versa.

Children, adolescents, and young adults (18 to 24 years of age) with major depressive disorder and other psychiatric disorders may be at an increased risk of suicidal thinking and suicidality with antidepressant use, particularly during the first few months of treatment. Medical evidence has not shown this increased risk to exist in adults older than 24 years of age, but adults 65 years of age and older taking antidepressants appear to have a decreased risk of suicidality. The results of a meta-analysis indicate an overall favorable risk-to-benefit profile for the use of antidepressants (i.e., selective serotonin and/or norepinephrine reuptake inhibitors) in the treatment of pediatric patients (less than 19- years- old) with major depressive disorders (MDD), obsessive-compulsive disorder (OCD), or non- OCD anxiety disorders. Although this study also reports an overall increased risk of suicidal ideation/suicide attempt associated with the use of antidepressants in pediatric patients, the risk may be less than originally estimated. Additional prospective studies are warranted in order to confirm these findings.

Worsening of depression and/or increased suicidal thinking or behavior may always be a possibility in patients treated with antidepressant medications, particularly those being treated for depression. Anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, akathisia (severe restlessness), hypomania, and mania have been reported in patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric. It is unknown if these symptoms are a precursor to either worsening of depression or the emergence of suicidal impulses; however, there is concern that patients who experience one or more of these symptoms may be at increased risk for worsening depression or suicidality. Although the FDA has not concluded that antidepressant drugs cause worsening depression or suicidality, health care providers should be aware that worsening of symptoms could be due to the underlying disease or might be a result of drug therapy.

Health care providers should carefully monitor patients receiving antidepressants for possible and/or persistent worsening of depression or emergent suicidality, especially at the beginning of therapy or when the dose either increases or decreases. If symptoms are severe, abrupt in onset, or were not part of the patient's presenting symptoms, the health care provider will need to determine what intervention, including discontinuing or modifying the current drug therapy, is indicated. Prescriptions should be written for small quantities of drug to reduce the risk of an attempt to overdose. Health care providers should instruct patients, their families and their caregivers to be alert for the emergence of agitation, irritability, and the other symptoms described above, as well as the emergence of suicidality and worsening depression, and to report such symptoms immediately to their health care provider.

Because antidepressants are believed to have the potential for inducing manic episodes in patients with bipolar disorder, there is a concern about using antidepressants alone in this population. Therefore, patients should be adequately screened to determine if they are at risk for bipolar disorder before initiating antidepressant treatment so that they can be appropriately monitored during treatment. Such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression.

Concomitant use of amitriptyline and potent inhibitors of CYP450 2D6 (e.g., terbinafine) may result in a significant and prolonged increase in amitriptyline and nortriptyline serum concentrations.

Dialysis

Amitriptyline is not dialyzable.

Other Comments

An adequate therapeutic effect may take as long as 30 days to develop. The effects with IM administration may appear more rapidly than with oral administration.

Therapy should not be discontinued abruptly after long-term use.

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