pimozide

pimozide /pi·mo·zide/ an antipsychotic and antidyskinetic agent used in the treatment of Gilles de la Tourette's syndrome.

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pim·o·zide (pm-zd)

n.

An antipsychotic drug used to treat chronic schizophrenia and in the management of Tourette's syndrome.

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pimozide

[pim′əzīd]

an antipsychotic agent from the diphenylbutylpiperidine class.

indications It is prescribed for the suppression of motor and phonic tics associated with Gilles de la Tourette's syndrome.

contraindications It may cause electrocardiography changes, including a prolonged QT interval, and should not be given to patients with a congenital prolonged QT interval or a history of cardiac arrhythmias. It also may lower the seizure threshold of patients who are also taking an anticonvulsant drug. It should not be taken concurrently with drugs that are inhibitors of CYP3a4 (e.g., ketoconazole, erythromycin).

adverse effects Among the more serious adverse effects are extrapyramidal effects, persistent tardive dyskinesia, sedation, drowsiness, constipation, dry mouth, visual disturbances, and electrocardiograph changes.

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pimozide,

n brand name: Orap;
drug class: antipsychotic, antidyskinetic;
action: blocks dopamine effects on central nervous system;
uses: motor and phonic tics in Giles de la Tourette's syndrome.

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pimozide

an antipsychotic agent in humans; used for its long-acting central antiemetic effect in dogs.

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pimozide

Orap

Pharmacologic class: Diphenylbutylpiperidine

Therapeutic class: Antipsychotic

Pregnancy risk category C

Action

Unclear. Thought to relieve tics by blocking dopaminergic receptors on neurons in CNS.

Availability

Tablets: 1 mg, 2 mg

⊘Indications and dosages

➣ Motor and phonic tics in Tourette's syndrome

Adults: Initially, 1 to 2 mg P.O. daily in divided doses, increased every other day p.r.n. For maintenance, 0.2 mg/kg/day or 10 mg/day (whichever is smaller).

Contraindications

• Hypersensitivity to drug
• Severe toxic CNS depression
• Congenital long-QT syndrome
• History of arrhythmias
• Concurrent use of itraconazole, ketoconazole, macrolide antibiotics, protease inhibitors, nefazodone, or other drugs that prolong QT interval or cause motor and phonic tics
• Simple tics or tics other than those associated with Tourette syndrome

Precautions

Use cautiously in:
• history of seizures, cardiovascular disorders, hepatic or renal dysfunction, ECG abnormalities
• disorders that could be aggravated by adverse anticholinergic effects
• pregnant or breastfeeding patients
• children younger than age 12.

Administration

• Give with or without food.
• To minimize daytime sedation, give entire daily dose at bedtime.

Route	Onset	Peak	Duration
P.O.	Unknown	6-8 hr	Unknown

Adverse reactions

CNS: drowsiness, headache, dizziness, insomnia, akathisia, rigidity, speech disorder, handwriting changes, sedation, depression, excitement, nervousness, abnormal dreams, hyperkinesia, tardive dyskinesia, parkinsonian-like symptoms, tremor, neuroleptic malignant syndrome

CV: abnormal ECG, hypotension, orthostatic hypotension, hypertension, palpitations, chest pain, tachycardia, prolonged QT interval

EENT: visual disturbance, perception of spots before eyes, decreased visual accommodation

GI: nausea, vomiting, diarrhea, constipation, eructation, dysphagia, excessive salivation, dry mouth

GU: urinary frequency, menstrual disorder, breast secretions, erectile dysfunction, libido loss

Musculoskeletal: muscle cramps or tightness, stooped posture, torticollis

Skin: rash, skin irritation, sweating, photosensitivity

Other: taste changes, thirst, appetite changes, weight gain or loss

Interactions

Drug-drug. Amphetamines, methylphenidate, pemoline: tics

Antiarrhythmics, azole antifungals, macrolide antibiotics, phenothiazines, protease inhibitors, tricyclic antidepressants: ECG abnormalities

Anticholinergics: increased anticholinergic effects

CNS depressants: additive CNS depression

Drug-diagnostic tests. ECG: abnormalities

Drug-food. Grapefruit juice: inhibited pimozide metabolism

Drug-behaviors. Alcohol use: increased CNS depression

Patient monitoring

☞ Assess neurologic status, especially for signs and symptoms of neuroleptic malignant syndrome (high fever, stupor, sweating, unstable blood pressure, muscle rigidity, and autonomic dysfunction) and parkinsonian-like symptoms.
• Monitor for tardive dyskinesia, even after drug therapy ends.
• Assess vital signs and ECG. Stay alert for prolonged QT interval, hypertension, or orthostatic hypotension.

Patient teaching

• Tell patient he may take with or without food but not with grapefruit juice.
• Caution patient not to stop taking suddenly. Dosage must be tapered.
☞ Teach patient to recognize and immediately report signs and symptoms of neuroleptic malignant syndrome and tardive dyskinesia. Tell patient tardive dyskinesia may develop long after drug therapy ends.
• Instruct patient to rise slowly and carefully, because blood pressure may drop if he stands up suddenly.
• Advise patient that drug may cause erectile dysfunction and libido loss. Encourage him to discuss these problems with prescriber.
• Tell patient drug may cause appetite changes. Encourage good nutrition.
• Inform patient that drug may cause vision changes and photosensitivity, which he should report.
• Instruct patient not to drink alcohol or grapefruit juice while taking drug.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and behaviors mentioned above.