Pimozide Side Effects

It is possible that some side effects of pimozide may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to pimozide: oral tablet

Along with its needed effects, pimozide may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking pimozide:

More common
  • Difficulty with speaking
  • dizziness or fainting
  • fast or irregular heartbeat
  • lack of facial expression
  • loss of balance control
  • mood or behavior changes
  • restlessness or need to keep moving
  • shuffling walk
  • slowed movements
  • stiffness of the arms and legs
  • swelling or soreness of the breasts (less common in males)
  • trembling and shaking of the fingers and hands
  • unusual secretion of milk (rare in males)
Less common or rare
  • Difficulty with swallowing
  • inability to move the eyes
  • increased blinking or spasms of the eyelid
  • lip smacking or puckering
  • menstrual changes
  • muscle spasms, especially of the face, neck, or back
  • puffing of the cheeks
  • rapid or worm-like movements of the tongue
  • skin rash and itching
  • sore throat and fever
  • swelling of the face
  • uncontrolled chewing movements
  • uncontrolled movements of the neck, trunk, arms, or legs, including twisting movements
  • unusual bleeding or bruising
  • unusual facial expressions or body positions
  • yellow eyes or skin
Rare
  • Convulsions (seizures)
  • difficult or unusually fast breathing
  • fast heartbeat or irregular pulse
  • fever (high)
  • high or low (irregular) blood pressure
  • increased sweating
  • loss of bladder control
  • muscle stiffness (severe)

Get emergency help immediately if any of the following symptoms of overdose occur while taking pimozide:

Symptoms of overdose
  • Coma
  • dizziness (severe)
  • muscle trembling, jerking, or stiffness (severe)
  • troubled breathing (severe)
  • uncontrolled movements (severe)

Some side effects of pimozide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Blurred vision or other vision problems
  • constipation
  • dizziness, lightheadedness, or fainting when getting up from a lying or sitting position
  • drowsiness
  • dryness of the mouth
  • skin discoloration
Less common
  • Decreased sexual ability
  • diarrhea
  • headache
  • loss of appetite and weight
  • mental depression
  • nausea and vomiting
  • tiredness or weakness

For Healthcare Professionals

Applies to pimozide: oral tablet

Musculoskeletal

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.

Other

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

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

Nervous system side effects including grand mal seizures have been reported at higher dosages.

Ocular

Ocular side effects including oculogyric crisis have been reported.

Oncologic

Oncologic side effects have been reported in animal studies. Animal studies have reported a dose related increase in pituitary and mammary tumors.

Gastrointestinal

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.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

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