imipramine

Imipramine is a tricyclic antidepressant (TCA) used to treat depressive disorders and certain anxiety conditions. Marketed under brand names such as Tofranil, it is also prescribed in generic form in many countries. It has been used for major depressive disorder, panic disorder, and nocturnal enuresis in children.

Its primary mechanism is inhibition of norepinephrine and serotonin reuptake, increasing monoamine levels in the synapse. It also has antagonistic effects at muscarinic, histaminergic, and alpha-adrenergic receptors, contributing to both therapeutic effects and the characteristic side effect profile.

Clinical uses include major depressive disorder and some anxiety disorders; it remains a second-line option due to safety concerns, with enuresis in children as a historical indication. It is generally not preferred as first-line therapy when safer antidepressants are available.

Pharmacokinetics: Imipramine is well absorbed orally and is extensively metabolized in the liver to active metabolites such as desipramine. It has a variable half-life and is mainly cleared by hepatic pathways.

Safety: Common adverse effects include dry mouth, constipation, blurred vision, urinary retention, drowsiness, weight change, and orthostatic hypotension. Overt toxicity can cause cardiac arrhythmias; drug interactions with MAO inhibitors, other CNS depressants, and QT-prolonging drugs require caution. Contraindications include recent myocardial infarction and certain conduction disorders.