[Examples: Amitriptyline (Rx Elavil), Imipramine (Rx Tofranil), and Doxepin (Rx Sinequan)]
Pharmacologic Mechanism of Action
The mechanism of action of amitriptyline hydrochloride is not definitely known. However, we know that it does not act primarily by stimulation of the central nervous system. The clinical effect is hypothesized as being due to potentiation of adrenergic synapses by blocking uptake of norepinephrine and serotonin at nerve endings.
The time to onset of effect (i.e., relief of depression) varies from person to person, but typically takes an average of 1-3 weeks (and sometimes as long as 4-6 weeks) before mood improvement is noticed.
Indications
For the relief of symptoms of depression. Endogenous depression (i.e., meets DMS-IV criteria for melancholic features) is more likely to be alleviated than other depressive states. One to three weeks of treatment may be needed before optimal therapeutic effects are evident.
Dosage and Administration
Depression—Lower dosages are recommended for elderly patients and adolescents. Dosage should be initiated at a low level and increased gradually, noting carefully the clinical response and any evidence of intolerance. Following remission, maintenance medication may be required for a longer period of time at the lowest dose that will maintain remission.
| Usual Adult Oral Dose: |
| Hospitalized patients—Initially, 100 mg/day in divided doses gradually increased to 200 mg/day as required. If no response after two weeks, increase to 250-300 mg/day. |
| Outpatients—Initially, 75 mg/day increased to 150 mg/day. Dosages over 200 mg/day are not recommended. Maintenance, 50-150 mg/day. |
Side Effects
| Common—Dry mouth; dizziness, lightheadedness or fainting may occur; headache; increased appetite and cravings; constipation. |
| Less common—Anxiety, restlessness, agitation; insomnia and nightmares; irregular heartbeat; confusional states (especially in the elderly) with hallucinations, disorientation, delusions. |
| Symptoms of acute overdose—Confusion, convulsions, enlarged pupils, irregular heartbeat, vomiting. |
Precautions:
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Cost
Tablets: $3.75 for generic, for a 3-month supply of 100 75mg tablets ($98.17 for Elavil). The cost can be lower depending on the individual's medical insurance. Available by prescription only, so one must have an appointment with a physician or nurse practitioner for diagnosis and treatment. (Appointments may be available for a minimum cost at the college health center.)
Resource: Much of the material on this sheet is quoted directly from http://www.rxlist.com/cgi/generic/amitrip.htm and is used with permission.