What is the dose of amitriptyline (Amitriptyline)

From the Guidelines

The typical starting dose of amitriptyline for adults is 25-50 mg taken orally at bedtime, which can be gradually increased to 75-150 mg per day if needed, as recommended by the most recent and highest quality study 1.

Key Considerations

• For elderly patients or those with certain health conditions, a lower starting dose of 10-25 mg is often recommended, as seen in studies such as 1 and 1.
• The medication should be taken consistently, preferably at the same time each evening, as its sedative effects can help with sleep.
• Amitriptyline requires several weeks (usually 2-4 weeks) to reach full therapeutic effect for conditions like depression or chronic pain.
• The dosage should always be individualized based on patient response and tolerance to side effects, which may include drowsiness, dry mouth, constipation, and blurred vision.

Mechanism of Action

• Amitriptyline works by increasing levels of serotonin and norepinephrine in the brain, which helps regulate mood and pain perception, as discussed in 1.

Important Warnings

• It's essential to never stop taking amitriptyline suddenly, as this can cause withdrawal symptoms; instead, the dose should be gradually reduced under medical supervision, as advised in 1.

Side Effects and Interactions

• Common side effects of amitriptyline include drowsiness, dry mouth, constipation, and blurred vision, as reported in studies such as 1 and 1.
• Patients should be monitored for potential interactions with other medications and for signs of adverse effects, such as anticholinergic symptoms, as noted in 1.

From the FDA Drug Label

1. Dosage and Administration Oral Dosage Dosage should be initiated at a low level and increased gradually, noting carefully the clinical response and any evidence of intolerance. Initial Dosage for Adults For outpatients, 75 mg of amitriptyline HCl a day in divided doses is usually satisfactory. If necessary, this may be increased to a total of 150 mg per day Increases are made preferably in the late afternoon and/or bedtime doses. The usual maintenance dosage of amitriptyline HCl is 50 to 100 mg per day. In some patients, 40 mg per day is sufficient. Adolescent and Elderly Patients In general, lower dosages are recommended for these patients Ten mg 3 times a day with 20 mg at bedtime may be satisfactory in adolescent and elderly patients who do not tolerate higher dosages.

The dose of amitriptyline is:

• Initial dose for outpatients: 75 mg per day in divided doses, which can be increased to a total of 150 mg per day if necessary.
• Maintenance dose: 50 to 100 mg per day, with some patients requiring as little as 40 mg per day.
• Adolescent and elderly patients: 10 mg 3 times a day with 20 mg at bedtime, which may be satisfactory for those who do not tolerate higher dosages 2.

From the Research

Dose of Amitriptyline

• The dose of amitriptyline varies depending on the condition being treated, with doses generally between 25 mg and 125 mg 3, 4.
• For chronic neuropathic pain and fibromyalgia, doses of amitriptyline are usually below those at which the drugs act as antidepressants 3, 4.
• In the treatment of fibromyalgia, the daily dose of amitriptyline is typically 25 mg to 50 mg 4.
• For migraine prevention, amitriptyline is often used at traditional doses, although the exact dose is not specified in the studies 5, 6.

Factors Associated with Traditional Doses

• Male sex, age 65-80 years, and age ≥ 80 years are associated with traditional dose prescriptions of amitriptyline 6.
• Headaches, receiving medical aids, and being prescribed benzodiazepines or zolpidem concomitantly are also associated with traditional dose prescriptions of amitriptyline 6.
• The prevalence of prescriptions and proportion of traditional doses of amitriptyline tend to decrease over time 6.

Adverse Events

• More participants experience at least one adverse event with amitriptyline compared to placebo, with a risk ratio of 1.5 (95% CI 1.4 to 1.7) 3.
• Adverse events include nausea, dry mouth, dizziness, constipation, insomnia, asthenia, and hypertension 7, 5.
• The number needed to treat to harm is 4.1 (95% CI 3.2 to 5.7) 3.