Pimozide Side Effects

Common Side Effects

• Approximately 7 to 14 percent of pimozide users report drowsiness or falling asleep after taking the drug, making these its most common side effects. Restlessness and the inability to move are also common, occurring in 8 percent of users. More than 5 percent of patients who take pimozide experience dry mouth and behavior problems, such as a lack of self control.
  
  

Other Side Effects

• Pimozide also has the potential to cause a number of other troublesome or annoying, but not dangerous, side effects. Some patients experience gastrointestinal side effects from the drug, such as diarrhea, constipation and increased thirst or appetite. Nervous system and sensory effects like insomnia, changes in handwriting, depression, nervousness, changes in the taste of food and visual sensitivity to light as well as headaches are also possible while taking pimozide. Other possible side effects of pimozide include muscle cramps, stooped posture and impotence.
  
  

Drug Interactions

• There are some medications which produce unwanted side effects when used in conjunction with pimozide. Because it often causes drowsiness, be careful not to mix pimozide with other drugs that make you sleepy as this could seriously impair your ability to remain alert. Examples of drugs to avoid include narcotics, sleeping pills and sedatives, antiepileptic drugs, and anti-anxiety medications. A number of drugs have the potential to cause irregular heartbeat when mixed with pimozide, including tricyclic antidepressants, macrolide antibiotics and antiretroviral drugs.
  
  

Risks

• In addition to minor side effects and the risk of interactions, pimozide has the potential to cause serious medical complications. Serious neurological side effects include speech difficulties, sudden rigidity that makes simple movements difficult, and visual disturbances occur in at least 2 percent of patients. More rarely, pimozide causes seizures in patients. In some instances, pimozide use leads to the development of Neuroleptic Malignant Syndrome (NMS), a life-threatening condition. NMS causes a number of symptoms, including unresponsiveness or catatonia, irregular heartbeat and kidney failure. Another extremely rare side effect of pimozide use is sudden death.
  
  

Considerations

• Since it impairs reflexes and alertness, you should not operate a motor vehicle or heavy machinery while taking pimozide. It is also important to avoid alcohol as drinking exacerbates the side effects of pimozide. If you suddenly stop taking pimozide, you may experience a sudden increase in tics or other symptoms, making it important to always keep your medicine well-stocked and to avoid missing doses. Pimozide can cause birth defects and fetal death and is avoided during pregnancy. In addition, pimozide is not used in children under the age of two.