Trimipramin

Trimipramin, marketed under brand names such as Surmontil, is a tricyclic antidepressant (TCA) used primarily for the treatment of major depressive disorder. It is noted for a pronounced sedative effect and is sometimes chosen when sleep disturbance accompanies depression. It may also be prescribed off-label for anxiety or insomnia in some cases.

Pharmacology: Trimipramin inhibits the reuptake of norepinephrine and serotonin, increasing their levels in the synapse. It also antagonizes several receptors, including histamine H1, alpha-1 adrenergic, and muscarinic receptors, contributing to sedation and anticholinergic side effects. The drug is lipophilic, has extensive hepatic metabolism, and forms active metabolites. It is administered orally and often started at a low dose with gradual titration.

Clinical use and dosing: Dosing is individualized and guided by response and tolerability; therapy may take several weeks to show effect. Because of its sedative profile, it is typically used when daytime sleep disturbance is present. It should be used with caution in older patients and in those with cardiovascular disease, glaucoma, urinary retention, or a history of seizures.

Side effects and safety: Common adverse effects include sedation, drowsiness, dry mouth, constipation, blurred vision, dizziness, and orthostatic hypotension. Weight gain, tachycardia, and urinary retention can occur. Overdose with TCAs can be dangerous; patients should seek urgent care if an overdose is suspected. Safety in pregnancy and lactation is not established; use only if clearly indicated.

Interactions and contraindications: Trimipramin is contraindicated with concurrent monoamine oxidase inhibitors and should be used cautiously with other serotonergic drugs. It can interact with central nervous system depressants, other antihistamines, and medications affecting heart conduction.