Pimozide
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| 1-[1-[4,4-bis(4-fluorophenyl)butyl]- 4-piperidinyl]-1,3-dihydro-2H-benzimidazole-2-one | |
| CAS number 2062-78-4 | ATC code N05AG02 |
| Chemical formula | C28H29F2N3O |
| Molecular weight | 461.56 |
| Bioavailability | ? |
| Metabolism | ? |
| Elimination half-life | ? |
| Excretion | ? |
| Pregnancy category | ? |
| Legal status | ? |
| Routes of administration | ? |
Pimozide (Orap®) is an antipsychotic drug. As it has severe side effects, it is considered a drug of last resort, typically prescribed only after the patient has failed to respond to other medications. The side effects include tardive dyskinesia, neuroleptic malignant syndrome and long QT syndrome.
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Uses
Pimozide is used in its oral preparation in schizophrenia, Gilles de la Tourette syndrome and chronic psychosis. In dermatology, it is used to treat delusions of parasitosis (the perception that one is infested with parasites).
Chemistry
Pimozide is a diphenylbutylpiperidine derivative.
Pharmacology
Pharmacokinetics
Plasma levels of pimozide can vary widely between patients, and in insufficient response therapeutic drug monitoring may be required to ascertain that the patient is developing adequate plasma levels before withdrawing the drug and attempting other antipsychotics
Pharmacodynamics
Pimozide is an inhibitor of the type 2 dopamine receptor (D2).
Side-effects
Pimozide can have severe, potentially fatal side-effects. As with other dopamine antagonists Pimozide can cause various extrapyramidal side-effects, tardive dyskinesia and neuroleptic malignant syndrome.
In particular, Pimozide is known for causing the unpleasant extrapyramidal side-effect akathisia (commonly referred to as "restless pacing") in a large percentage of those who take it. This "restlessness" can sometimes be treated with anticholinergic drugs (mainly benztropine), beta blockers or benzodiazepines. Unfortunately, in many cases this side effect can be so intense that even large doses of these drugs are unable to counter it, and often is so extreme that self-destructive behaviour, including attempting suicide, may occur.
Reference
- Van Vloten WA. Pimozide: Use in Dermatology. Dermatol Online J 2003;9(2):3 (fulltext (http://dermatology.cdlib.org/92/reviews/pimozide/vanvloten.html))
External link
- http://www.mentalhealth.com/drug/p30-o01.html (A medical white paper on its use)