Paroxetine

In medicine, paroxetine is a second-generation antidepressant used for treating major depression. Its pharmacological action is a serotonin uptake inhibitor.

In the United States, it is marketed paroxetine hydrochloride (e.g., Paxil®, Paxil CR®) and as paroxetine mesylate (i.e., Pexeva®). The two salts are pharmacologically similar, but cannot be interchaged at the same dose.

Indications

The drug is approved by the U.S. Food and Drug Administration for depression, generalized anxiety disorder, obsessive-compulsive disorder, panic disorder, post-traumatic stress disorder and social phobia. It is often prescribed for the "off-label" indications of Depression associated with manic depressive disorder, fibromyalgia, premenstrual dysphoric disorder and vasomotor symptoms associated with menopause.

There have been limited trials with the drug as a prophylactic for migraine. While the second-generation antidepressants generally have not shown effectiveness in chronic pain, while tricyclic antidepressants often are useful, paroxetine has been compared to the tricyclic imipramine and appeared, in a small trial, to be more effective.

Pharmacology

Metabolism

Paroxetine is metabolized in the liver by cytochrome P-450 CYP2D6.

Drug interactions

Paroxetine may increase death from breast cancer among women taking tamoxifen due to inhibiting metabolism of tamoxifen to its active metabolite by cytochrome P-450 CYP2D6.