Zimelidine

| elimination_half-life = 8.4±2 hours (parent compound) 19.4±3.6 hours (norzimelidine)

Zimelidine (INN, BAN; brand names Zimeldine, Normud, Zelmid) , is an antidepressant medication of the selective serotonin reuptake inhibitor (SSRI) class, and the first SSRI antidepressant to be marketed. It is a pyridylallylamine, and is structurally different from other antidepressants.

Zimelidine was developed in the late 1970s and early 1980s by Arvid Carlsson, Hans Corrodi and Peter Berntsson, who were then working for the Swedish company Astra AB. Their work began with a series of antihistamines known as pheniramines that were found to block both serotonin and noradrenaline reuptake, and among these, brompheniramine was identified as the most potent serotonin reuptake blocker and was therefore selected as the starting point for their synthesis program, ultimately leading to the invention of zimelidine as a derivative of brompheniramine. Zimelidine was first sold in 1982.

While zimelidine had a very favorable safety profile comparing to other commonly used antidepressants like tricyclic antidepressants at the time it was developed, within a year and a half of its introduction, rare case reports of Guillain–Barré syndrome emerged that appeared to be caused by the drug, prompting its manufacturer to withdraw it from the market. Its withdrawal, due to this unpredictable neurological side effect, marked a swift end to its clinical use despite its pioneering efficacy. After its withdrawal, it was succeeded by fluoxetine (derived from the antihistamine diphenhydramine) and fluvoxamine in that order, and the other SSRIs.