Brand name: Paxil, Pexeva

Generic name: Paroxetine

Preparation(s): tablet, liquid

Uses for IBS:
Paxil (paroxetine) is an antidepressant that some studies have found very helpful in the treatment of irritable bowel syndrome. It is a serotonin specific reuptake inhibitor (SSRI), a class of drugs very popular for treating depression. However, Paxil has been very effective for the treatment of IBS with or without depression. Some experts believe that Paxil has been useful primarily because of the abundant gastrointestinal (GI) location of the neurotransmitter, serotonin. Serotonin has been implicated in the perception of pain. By blocking the serotonin receptors, Paxil decreases stimulation for intestinal contraction, thereby decreasing pain. It also decreases the IBS symptoms of urgency, straining, and the bothersome feeling of incomplete evacuation. Paxil is administered orally by tablet or suspension. Through its effects in the brain, Paxil can improve mood and overall approach to daily living, including sleep, appetite, and energy level.

Paxil should be avoided in those who have a hypersensitivity to paroxetine. It also should not be taken in combination with monoamine oxidase inhibitors (MAOIs) or thioridazine. Severe reactions such as seizures, agitation, delirium, and death could occur. Other medications that should not be mixed with Paxil include nefazodone (Serzone), dexfenfluramine (Redux), and terfenadine (Seldane).

The following medications can cause severe or moderate interactions with Paxil and should be used with caution: linezolid (Zyvox), venlafaxine (Effexor), phentermine (Adipex, Fastin), trazadone (Desyrel), tamoxifen (Nolvadex), and aspirin.

Paxil’s use in children and adolescents has a Black Box warning because it can increase the risk of suicide and it is not recommended because of the increased risk of suicidality. Although it is not suggested for use in pregnancy, if necessary, a physician can advise the safest schedule possible.

Adverse effects
The most frequent adverse effects include nausea and vomiting, drowsiness, decreased sexual ability, weakness or tiredness, dry mouth, problems with sleeping, and urinary retention.

Less frequent side effects include gastrointestinal pain and cramps, restlessness and anxiety, blurred vision, decreased libido, and numbness and tingling of the extremities.

Rare side effects include hallucinations, amnesia, increased risk of gastrointestinal bleeding, and serotonin syndrome. Serotonin syndrome occurs when the body has too much serotonin. This can be caused by either an increase in production or release of serotonin or when the elimination is disturbed. Serotonin syndrome occurs most commonly when other antidepressant medications (for example amitriptyline) are combined with Paxil. Symptoms include a rapid heart rate, stiff muscles, and seizures.