Anxiety disorders, Depression, Insomnia.
Tricyclic & related anti-depressant drugs
Doxepin binds with high affinity to the histamine H1 receptor (Ki<1 nM) where it functions as an antagonist. The exact mechanism by which doxepin exerts its sleep maintenance effect is unknown but is believed due to its antagonism of the H1 receptor.
Adult: As hydrochloride: Initially, 75 mg daily adjusted according to response; up to 300 mg daily in severely depressed patients; 25-50 mg daily in mildly affected patients. Total daily dose >100 mg should be given in divided doses. May be taken with or without food.
Cytochrome P450 Isozymes: Doxepin is primarily metabolized by hepatic cytochrome P450 isozymes CYP2C19 and CYP2D6, and to a lesser extent, by CYP1A2 and CYP2C9. Inhibitors of these isozymes may increase the exposure of doxepin. Doxepin is not an inhibitor of any CYP isozymes at therapeutically relevant concentrations. The ability of Doxepin to induce CYP isozymes is not known.
Cimetidine: Doxepin exposure is doubled with concomitant administration of cimetidine, a nonspecific inhibitor of CYP isozymes. A maximum dose of 3 mg is recommended in adults and elderly when cimetidine is co administered with Doxepin.
Alcohol: When taken with Doxepin, the sedative effects of alcohol may be potentiated.
CNS Depressants and Sedating Antihistamines: When taken with Doxepin, the sedative effects of sedating antihistamines and CNS depressants may be potentiated.
Tolazamide: A case of severe hypoglycemia has been reported in a type II diabetic patient maintained on tolazamide (1 g/day) 11 days after the addition of oral doxepin (75 mg/day).
Hypersensitivity; mania, glaucoma, neonates (topical); lactation. Epilepsy, CV disease, pregnancy, history of urinary retention, glaucoma; gradual withdrawal. May impair ability to drive or operate machinery.
Sedation, fatigue, weakness, lethargy, Dry mouth, Constipation, Blurred vision, Headache, Agitation, Insomnia, Anxiety, Nausea, vomiting, Sweating, Confusion, extrapyramidal symptoms (EPS), dizziness, paresthesia, Orthostatic hypotension, ECG changes, tachycardia, Increased LFTs, Tinnitus, Sexual dysfunction, Rash, Seizure, Agranulocytosis, Thrombocytopenia, Eosinophilia.
Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.
.png&w=384&q=75)