Pimozide Side Effects

Medically reviewed by Drugs.com. Last updated on Jan 12, 2024.

Applies to pimozide: oral tablet.

Serious side effects of pimozide

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)

Other side effects of pimozide

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.

General

The most common side effects include somnolence, hyperhidrosis, nocturia, and dizziness.^[Ref]

Nervous system

• Very common (10% or more): Somnolence (up to 25%), dizziness (up to 11%)
• Common (1% to 10%): Extrapyramidal disorder, akathisia, headache, lethargy, tremor, hyperkinesia, limb tremor, torticollis
• Uncommon (0.1% to 1%): Bradykinesia, cogwheel rigidity, dyskinesia, dystonia, dysarthria
• Frequency not reported: Neuroleptic malignant syndrome, grand mal convulsion, tardive dyskinesia, electroencephalogram abnormal, motor restlessness, hyperreflexia, opisthotonos, drowsiness, sedation, speech disorder, handwriting change, taste change, akinesia, parkinsonism, fainting
• Postmarketing reports: Seizure^[Ref]

Extrapyramidal symptoms typically occurred during the first few days of treatment and involved mild to moderate Parkinson-like symptoms. This disorder is usually dose-related, with an increased occurrence and severity of symptoms with high doses; symptoms decreased or disappeared with lower doses. While these symptoms were usually reversible, a few cases of persistent symptoms required discontinuation.

Grand mal seizures occurred at doses greater than 20 mg/day.^[Ref]

Psychiatric

• Very common (10% or more): Adverse behavior effect (up to 22.2%)
• Common (1% to 10%): Depression, agitation, insomnia, abnormal dreams, restlessness, nervous
• Frequency not reported: Libido decreased/lost, excitement^[Ref]

Other

• Very common (10% or more): Asthenia (up to 13.8%)
• Common (1% to 10%): Extreme exhaustion
• Uncommon (0.1% to 1%): Face edema
• Frequency not reported: Neonatal drug withdrawal syndrome, body temperature dysregulation, hypothermia
• Postmarketing reports: Sudden, unexplained death, hyperpyrexia, thirst^[Ref]

Sudden, unexpected deaths have occurred at doses greater than 20 mg/day.^[Ref]

Dermatologic

• Very common (10% or more): Hyperhidrosis (up to 13%)
• Common (1% to 10%): Sebaceous gland overactivity, rash
• Uncommon (less than 1%): Pruritus
• Frequency not reported: Urticaria, skin irritation^[Ref]

Genitourinary

• Very common (10% or more): Nocturia (up to 12%)
• Common (1% to 10%): Urinary frequency, erectile dysfunction
• Uncommon (0.1% to 1%): Amenorrhea
• Frequency not reported: Galactorrhea, menstrual disorder, breast secretions, impotence^[Ref]

Gastrointestinal

• Common (1% to 10%): Constipation, dry mouth, vomiting, increased salivation/salivary hypersecretion, dysphagia
• Frequency not reported: Diarrhea, nausea, gastrointestinal distress
• Postmarketing reports: Gingival hyperplasia^[Ref]

Gingival hyperplasia occurred in animal models at high doses, but was reversible after discontinuation.^[Ref]

Musculoskeletal

• Common (1% to 10%): Muscle rigidity, myalgia
• Uncommon (0.1% to 1%): Muscle spasms
• Frequency not reported: Rigidity, neck rigidity, muscle cramps, muscle tightness, stooped posture^[Ref]

Ocular

• Common (1% to 10%): Vision blurred, visual disturbance
• Uncommon (0.1% to 1%): Oculogyric crisis
• Frequency not reported: Sensitivity of eyes to light, decrease accommodation, spots before eyes, periorbital edema, cataracts^[Ref]

Metabolic

• Common (1% to 10%): Anorexia, weight increased
• Frequency not reported: Hyperglycemia, hyponatremia, appetite increase, weight loss^[Ref]

Hyperglycemia occurred in patients with preexisting diabetes.^[Ref]

Cardiovascular

• Common (1% to 10%): ECG abnormal
• Frequency not reported: Torsade de Pointes, ventricular tachycardia/tachycardia, ventricular fibrillation, chest pain, postural hypotension/hypotension, hypertension, palpitations
• Postmarketing reports: Cardiac arrest, venous thromboembolism, deep vein thrombosis^[Ref]

Electrocardiographic changes include prolongation of the QT interval, flattening/notching/inversion of the T wave, and the appearance of U waves.^[Ref]

Endocrine

• Frequency not reported: Blood prolactin increases, gynecomastia^[Ref]

Renal

• Frequency not reported: Glycosuria^[Ref]

Hematologic

• Postmarketing reports: Hemolytic anemia^[Ref]

Respiratory

• Postmarketing reports: Pulmonary embolism^[Ref]

Further information

Pimozide side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer