The mechanism of action of maprotiline is not precisely known. It does not act primarily by stimulation of the central nervous system and is not a monoamine oxidase inhibitor. The postulated mechanism of maprotiline is that it acts primarily by potentiation of central adrenergic synapses by blocking reuptake of norepinephrine at nerve endings. This pharmacologic action is thought to be responsible for the drug's antidepressant and anxiolytic effects.

Maprotiline hydrochloride tablets are indicated for the treatment of depressive illness in patients with depressive neurosis (dysthymic disorder) and manic depressive illness, depressed type (major depressive disorder). Maprotiline is also effective for the relief of anxiety associated with depression

A single daily dose is an alternative to divided daily doses. Therapeutic effects are sometimes seen within 3 to 7 days, although as long as 2 to 3 weeks are usually necessary.

Initial Adult Dosage: An initial dosage of 75 mg daily is suggested for outpatients with mild to moderate depression. However, in some patients, particularly the elderly, an initial dosage of 25 mg daily may be used. Because of the long half-life of maprotiline, the initial dosage should be maintained for 2 weeks. The dosage may then be increased gradually in 25 mg increments as required and tolerated. In most outpatients, a maximum dose of 150 mg daily will result in therapeutic efficacy. It is recommended that this does not be exceeded except in the most severely depressed patients. In such patients, dosage may be gradually increased to a maximum of 225 mg.

More severely depressed, hospitalized patients should be given an initial daily dose of 100 mg to 150 mg which may be gradually increased as required and tolerated. Most hospitalized patients with moderate to severe depression respond to a daily dose of 150 mg although dosages as high as 225 mg may be required in some cases. The daily dosage of 225 mg should not be exceeded.

Elderly Patients: In general, lower dosages are recommended for patients over 60 years of age. Dosages of 50 mg to 75 mg daily are usually satisfactory as maintenance therapy for elderly patients who do not tolerate higher amounts.

Maprotiline hydrochloride tab lets are contraindicated in patients hypersensitive to maprotiline and in patients with known or suspected seizure disorders. It should not be given concomitantly with monoamine oxidase (MAO) inhibitors. A minimum of 14 days should be allowed to elapse after discontinuation of MAO inhibitors before treatment with maprotiline is initiated. Effects should be monitored with gradual increase in dosage until optimum response is achieved. The drug is not recommended for use during the acute phase of myocardial infarction.

Cardiovascular: Rare occurrences of hypotension, hypertension, tachycardia, palpitation, arrhythmia, heart block, and syncope have been reported with maprotiline.

Psychiatric: Nervousness (6%), anxiety (3%), insomnia (2%), and agitation (2%); rarely, confusional states (especially in the elderly), hallucinations, disorientation, delusions, restlessness, nightmares, hypomania, mania, exacerbation of psychosis, decrease in memory, and feelings of unreality

Neurological: Drowsiness (16%), dizziness (8%), tremor (3%), and, rarely, numbness, tingling, motor hyperactivity, akathisia, seizures, EEG alterations, tinnitus, extrapyramidal symptoms, ataxia, and dysarthria.

Anticholinergic: Dry mouth (22%), constipation (6%), and blurred vision (4%); rarely, accommodation disturbances, mydriasis, urinary retention, and delayed micturition.

Allergic: Rare instances of skin rash, petechiae, itching, photosensitization, edema, and drug fever.

Gastrointestinal: Nausea (2%) and, rarely, vomiting, epigastric distress, diarrhea, bitter taste, abdominal cramps and dysphagia.

Endocrine: Rare instances of increased or decreased libido, impotence, and elevation or depression of blood sugar levels.

The possibility of suicide in seriously depressed patients is inherent in their illness and may persist until significant remission occurs. Therefore, patients must be carefully supervised during all phases of treatment with maprotiline, and prescriptions should be written for the smallest number of tablets consistent with good patient management. Hypomanic or manic episodes have been known to occur in some patients taking tricyclic antidepressant drugs, particularly in patients with cyclic disorders. Such occurrences have also been noted, rarely, with maprotiline. Prior to elective surgery, ma protiline should be discontinued for as long as clinically feasible, since little is known about the interaction between maprotiline and general anesthetics. Maprotiline should be administered with caution in patients with a history of urinary retention, or a history of narrow-angle glaucoma because of the drug’s anticholinergic properties.

Pregnancy & Lactation

Pregnancy Category B. Reproduction studies have been performed in female laboratory rabbits, mice, and rats at doses up to 1.3, 7, and 9 times the maximum daily human dose respectively and have revealed no evidence of impaired fertility or harm to the fetus due to maprotiline. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Labor and Delivery: Although the effect of maprotiline on labor and delivery is unknown, caution should be exercised as with any drug with CNS depressant action.

Nursing Mothers: Maprotiline is excreted in breast milk. At steady-state, the concentrations in milk correspond closely to the concentrations in whole blood. Caution should be exercised when maprotiline hydrochloride is administered to a nursing woman.