Pimozide Side Effects
Some side effects of pimozide may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to pimozide: oral tablet
Get emergency medical help if you have any of these signs of an allergic reaction while taking pimozide: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have a serious side effect such as:
twitching or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs; or
very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.
Less serious side effects of pimozide may include:
headache, dizziness, drowsiness;
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to pimozide: oral tablet
Musculoskeletal side effects including Parkinson-like symptoms have been reported frequently. Motor restlessness, dystonia, hyperreflexia, akathisia, and opisthotonos have been reported far less frequently. Pimozide has also been associated with persistent dyskinesia.
Parkinson-like symptoms were usually mildly to moderately severe and usually reversible. Generally, the occurrence and severity of most extrapyramidal symptoms are felt to be dose related. Administration of antiparkinson drugs such as benztropine mesylate or trihexyphenidyl hydrochloride may be required to control Parkinson-like symptoms.
The risk of developing tardive dyskinesia has been reported to be greater among elderly patients on high-dose therapy, especially females. It has been reported that fine vermicular movement of the tongue may be an early sign of tardive dyskinesia and if the medication is stopped at that time, the syndrome may not develop.
It is not known whether gradual withdrawal of antipsychotic drugs will reduce the rate of occurrence of withdrawal emergent neurological signs. However, until further evidence becomes available, it is recommended to gradually withdraw the use of pimozide.
Other side effects including neuroleptic malignant syndrome (NMS) and hyperpyrexia (not associated with NMS) have been reported. Transient dyskinetic signs after abrupt withdrawal from a maintenance treatment have also been reported.
Cardiovascular side effects have included prolongation of the QT interval, flattening, notching, and inversion of the T wave, and the appearance of U waves. Sudden, unexpected deaths have been reported at higher dosages.
Nervous system side effects including grand mal seizures have been reported at higher dosages.
Ocular side effects including oculogyric crisis have been reported.
Oncologic side effects have been reported in animal studies. Animal studies have reported a dose related increase in pituitary and mammary tumors.
The gingival hyperplasia was reversible after withdrawal of the drug.
Gastrointestinal side effects have been reported in animal studies. Chronic animal studies have reported that pimozide caused gingival hyperplasia.
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