Paroxetine

Brand Name:

Paxil

Drug Class:

Selective Serotonin Reuptake Inhibitor

How it works:

Boosts the effects of a neurotransmitter found in the brain called Serotonin. Also, it has mild anticholinergic activity that can cause dry eyes, dry mouth, and urinary retention. Paroxetine weakly increases the effect of a chemical found in the brain called norepinephrine.

What makes it unique:

Tends to be calming and even slightly sedating, which may make it good for anxiety.

It may inhibit nitric oxide, which is needed for proper sexual function.

It can commonly cause withdrawal symptoms if it is suddenly stopped or if a few doses are missed. Withdrawal from antidepressant medications is usually described by patients as being similar to a “mini flu”.

Side effects:

Headaches and stomach aches are common when starting, but then often goes away. Sexual dysfunction can also occur. Increased serotonin can cause diminished dopamine release, which may lead to emotional flattening and apathy in some patients. The mild anticholinergic activity that can cause dry eyes, dry mouth, and urinary retention.

Rare side effects include hyponatremia seizures, induction of mania, and activation of suicidal ideation in people age 24 and younger.

How effective is it:

(1) A meta-analysis was conducted of 39 randomized, double-blind studies that compared Paroxetine to tricyclic antidepressant medications. 3,617 patients in total were assessed. The study utilized the HAM-D depression score to track symptoms. The analysis found comparable response rates between the medications but the patients taking Paroxetine had slightly fewer side effects.

(2) A study compared the efficacy and tolerability of Paroxetine to an antidepressant in a different drug class called Mirtazapine. 275 patients were treated. Both medications were shown to be equally effective at decreasing depression scores, but Mirtazapine was shown to reach that point faster. Tolerability was similar between the two medications.

Clinical experience: 

This is not the most common medication but is still sometimes seen. This would be chosen over other options for a depressed patient who has trouble sleeping or is really on edge. Also, a patient would have to be very good at remembering their medications because they can feel crummy if just a dose or two is missed. Pharmaceuticals should never be used as the sole treatment for mental illnesses. Therapy, exercise, meditation or other treatments should always accompany prescriptions.

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References:

1. Montgomery S. A meta-analysis of the efficacy and tolerability of paroxetine versus tricyclic antidepressants in the treatment of major depression. Int Clin Psychopharmacol. 2001 May;16(3):169-78.

2. Benkert O, Szedegi A, Kohnen R. Mirtazapine compared with paroxetine in major depression. The Journal of Clinical Psychiatry [01 Sep 2000, 61(9):656-663].