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Orap (Pimozide) - Side Effects and Adverse Reactions




Extrapyramidal Reactions: Neuromuscular (extrapyramidal) reactions during the administration of ORAP (pimozide) have been reported frequently, often during the first few days of treatment. In most patients, these reactions involved Parkinson-like symptoms which, then first observed, were usually mild to moderately severe and usually reversible.

Other types of neuromuscular reactions (motor restlessness, dystonia, akathisia, hyperreflexia, opisthotonos, oculgyric crises) have been reported far less frequently. Severe extrapyramidal reactions have been reported to occur at relatively low doses. Generally the occurrence and severity of most extrapyramidal symptoms are dose-related since they occur at relatively high doses and have been shown to disappear or become less severe when the dose is reduced. Administration of antiparkinson drugs such as benztropine mesylate or trihexphenidyl hydrochloride may be required for control of such reactions. It should be noted that persistent extrapyramidal reactions have been reported and that the drug may have to be discontinued in such cases.

Withdrawal Emergent Neurological Signs: Generally, patients receiving short term therapy experience no problems with abrupt discontinuation of antipsychotic drugs. However, some patients on maintenance treatment experience transient dyskinetic signs after abrupt withdrawal. In certain of these cases the dyskinetic movements are indistinguishable from the syndrome described below under "Tardive Dyskinesia" except for duration. It is not known whether gradual withdrawal of antipsychotic drugs with reduce the rate of occurrence of withdrawal emergent neurological signs, but until further evidence becomes available, it seems reasonable to gradually withdraw use of ORAP.

Tardive Dyskinesia: ORAP may be associated with persistent dyskinesias. Tardive dyskinesia, a syndrome consisting of potentially irreversible, involuntary, dyskinetic movements, may appear in some patients on long-term therapy or may occur after drug therapy has been discontinued. The risk appears to be greater in elderly patients on high-dose therapy, especially females. The symptoms are persistent and in some patients appear irreversible. The syndrome is characterized by rhythmical unvoluntary movements of tongue, face, mouth or jaw (e.g., protrusions of tongue, puffing of cheeks, puckering of mouth, chewing movements). Sometimes these may be accompanied by involuntary movements of extremities and the trunk.

There is no known effective treatment for tardive dyskinesia; antiparkinson agents usually do not alleviate the symptoms of this syndrome. It is suggested that all antipsychotic agents be discontinued if these symptoms appear. Should it be necessary to reinstitute treatment, or increase the dosage of the agent, or switch to a different antipsychotic agent, this syndrome may be masked.

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.

Electrocardiographic Changes: Electrocardiographic changes have been observed in clinical trials of ORAP in Tourette's Disorder and schizophrenia. These have included prolongation of the QT interval, flattening, notching and inversion of the T wave and the appearance of U waves. Sudden, unexpected deaths and grand mal seizure have occurred at doses above 20 mg/day.

Neuroleptic Malignant Syndrome: Neuroleptic malignant syndrome (NMS) has been reported with ORAP. (See WARNINGS for further information concerning NMS.)

Hypergyrexia: Hyperpyrexia has been reported with other antipsychotic drugs.


The following adverse reaction tabulation was derived from 20 patients in a 6-week long placebo-controlled clinical trial of ORAP in Tourette's Disorder.

Body System/ Adverse Reaction Pimozide (N = 20) Placebo (N = 20)
Body as a Whole
Headache 1 2
Dry Mouth 5 1
Diarrhea 1 0
Nausea 0 2
Vomiting 0 1
Constipation 4 2
Eructations 0 1
Thirsty 1 0
Appetite increase 1 0
Menstrual disorder 0 1
Breast secretions 0 1
Muscle cramps 0 1
Muscle tightness 3 0
Stooped posture 2 0
Drowsiness 7 3
Sedation 14 5
Insomnia 2 2
Dizziness 0 1
Akathisia 8 0
Rigidity 2 0
Speech disorder 2 0
Handwriting change 1 0
Akinesia 8 0
Depression 2 3
Excitement 0 1
Nervous 1 0
Adverse behavior effect 5 0
Special Senses
Visual disturbance 4 0
Taste change 1 0
Sensitivity of eyes to light 1 0
Decrease accommodation 4 1
Spots before eyes 0 1
Impotence 3 0

The following adverse event tabulation was derived from 36 children (age 2 to 12) in a 24-week open trial of ORAP in Tourette's Disorder.

Body System/ Adverse Reaction Number of Patients Experiencing Each Event (%)
All Events (N=36) Drug-Related
Events (N=36)
Body as a Whole
Asthenia 9 (25.0) 5 (13.8)
Headache 8 (22.2) 1 (2.7)
Dysphagia 1 (2.7) 1 (2.7)
Increased Salivation 5 (13.8) 2 (5.5)
Myalgia 1 (2.7) 1 (2.7)
Central Nervous System
Dreaming Abnormal 1 (2.7) 1 (2.7)
Hyperkinesia 2 (5.5) 1 (2.7)
Somnolence 10 (27.7) 9 (25.0)
Torticollis 1 (2.7) 1 (2.7)
Tremor, Limbs 1 (2.7) 1 (2.7)
Adverse Behavior Effect 10 (27.7) 8 (22.2)
Nervous 3 (8.3) 2 (5.5)
Rash 3 (8.3) 1 (2.7)
Special Senses
Visual disturbance 2 (5.5) 1 (2.7)
ECG Abnormal 1 (2.7) 1 (2.7)

Because clinical investigational experience with ORAP in Tourette's Disorder is limited, uncommon adverse reactions may not have been detected. The physician should consider that other adverse reactions associated with antipsychotics may occur.


In addition to the adverse reactions listed above, those listed below have been reported in U.S. clinical trails of ORAP in conditions other than Tourette's Disorder.

Body as a Whole: Asthenia, chest pain, periorbital edema

Cardiovascular/Respiratory: Postural hypotension, hypotension, hypertension, tachycardia, palpitations

Gastrointestinal: Increased salivation, nausea, vomiting, anorexia, GI distress

Endocrine: Loss of libido

Metabolic/Nutritional: Weight gain, weight loss

Central Nervous System: Dizziness, tremor, parkinsonism, fainting, dyskinesia

Psychiatric: Excitement

Skin: Rash, sweating, skin irritation

Special Senses: Blurred vision, cataracts

Urogenital: Nocturia, urinary frequency


The following experiences were described in spontaneous postmarketing reports. These reports do not provide sufficient information to establish a clear causal relationship will the use of ORAP.

Gastrointestinal: Gingival hyperplasia in one patient

Hematologic: Hemolytic anemia

Metabolic/Nutritional: Hyponatremia

Other: Seizure


Below is a sample of reports where side effects / adverse reactions may be related to Orap. The information is not vetted and should not be considered as verified clinical evidence.

Possible Orap side effects / adverse reactions in 45 year old female

Reported by a health professional (non-physician/pharmacist) from France on 2011-10-05

Patient: 45 year old female

Reactions: Rhabdomyolysis, Vomiting, Diarrhoea, Inappropriate Antidiuretic Hormone Secretion, Hyponatraemia

Adverse event resulted in: hospitalization

Suspect drug(s):
    Administration route: Oral

    Administration route: Oral

Other drugs received by patient: Milligynon; Trihexyphenidyl Hydrochloride

Possible Orap side effects / adverse reactions in 45 year old female

Reported by a health professional (non-physician/pharmacist) from France on 2011-10-13

Patient: 45 year old female

Reactions: Vomiting, Rhabdomyolysis, Diarrhoea, Inappropriate Antidiuretic Hormone Secretion, Hyponatraemia

Adverse event resulted in: hospitalization

Suspect drug(s):
    Dosage: unk
    Administration route: Oral

    Dosage: unk
    Administration route: Oral

Other drugs received by patient: Trihexyphenidyl Hydrochloride; Milligynon

Possible Orap side effects / adverse reactions in 59 year old female

Reported by a consumer/non-health professional from United States on 2012-04-10

Patient: 59 year old female weighing 98.4 kg (216.5 pounds)

Reactions: Anxiety, Refusal of Treatment by Patient, Fear, Condition Aggravated, Tourette's Disorder

Suspect drug(s):
    Dosage: 5 mg;qd;po
    Administration route: Oral
    Indication: Tourette's Disorder
    Start date: 2012-03-28

Pimozide (NO Pref. Name)
    Dosage: 4 mg;qd;po
    Administration route: Oral
    End date: 2012-03-01

    Dosage: 2 mg;qd;po
    Administration route: Oral
    Indication: Tourette's Disorder
    Start date: 1985-01-01

    Dosage: 2 mg;qd;po
    Administration route: Oral
    Indication: Condition Aggravated
    Start date: 1985-01-01

Benztropine Mesylate
    Dosage: ;qd or bid;
    Indication: Adverse Event
    Start date: 2012-01-01
    End date: 2012-01-01

See index of all Orap side effect reports >>

Drug label data at the top of this Page last updated: 2006-07-19

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