Doxepin HCl Oral Capsule Dosage Recommendations

For most adult patients, the recommended dosage of Doxepin HCl oral capsules is 75-150 mg/day, with a maximum recommended dose of 300 mg/day. 1

Initial Dosing and Titration

For most patients with mild to moderate illness, the recommended starting daily dose is 75 mg 1
For patients with very mild symptomatology or emotional symptoms accompanying organic disease, lower doses of 25-50 mg/day may be sufficient 1
For more severely ill patients, higher initial doses may be required with subsequent gradual increases up to 300 mg/day if necessary 1
Additional therapeutic effect is rarely obtained by exceeding a dose of 300 mg/day 1

The total daily dosage may be given on a divided or once-a-day schedule 1
If using a once-a-day schedule, the maximum recommended dose is 150 mg/day, typically administered at bedtime 1, 2
Single daily bedtime dosing has been shown to maintain similar plasma levels as divided dosing, though it may cause more morning sedation 2

Lower doses should be used in elderly patients due to potential for decreased renal function 1
Elderly patients should be started on low doses and observed closely due to risk of confusion and oversedation 1

For sleep maintenance insomnia, lower doses of 3-6 mg are recommended 3
The American Academy of Sleep Medicine suggests doxepin as a treatment for sleep maintenance insomnia at these lower doses 3

For patients with chronic pain and depression, dosages up to 200 mg/day have shown efficacy 4
Improvements in both pain and depression symptoms have been observed at mean plasma levels of 80 ng/ml 4

While some sources have suggested a therapeutic range of 150-250 ng/ml (parent drug plus metabolite), this range may be too high 5
A working range of 50-250 ng/ml has been proposed based on reassessment of published data 5
There is limited correlation between plasma concentrations and clinical improvement 5

Anticholinergic effects: dry mouth, blurred vision, constipation, urinary retention 1
CNS effects: drowsiness (most common), confusion, disorientation, hallucinations 1
Cardiovascular effects: hypotension, hypertension, tachycardia 1
Dosage reduction may be necessary if side effects do not subside or become severe 1
Anti-anxiety effects may appear before antidepressant effects 1
Optimal antidepressant effect may take two to three weeks to become evident 1

The 150 mg capsule strength is intended for maintenance therapy only and is not recommended for initiation of treatment 1
Abrupt cessation after prolonged administration should be avoided; gradual withdrawal is recommended 1
Caution is required in patients with cardiovascular disease due to potential cardiac effects 1
Overdose can be life-threatening with symptoms including cardiac dysrhythmias, severe hypotension, convulsions, and CNS depression 1