Pimozide: Parasitosis (Delusional)

Abstract

This Hospital Pharmacy feature is extracted from Off-Label Drug Facts, a publication available from Wolters Kluwer Health. Off-Label Drug Facts is a practitioner-oriented resource for information about specific drug uses that are unapproved by the US Food and Drug Administration. This new guide to the literature enables the health care professional or clinician to quickly identify published studies on off-label uses and determine if a specific use is rational in a patient care scenario. References direct the reader to the full literature for more comprehensive information before patient care decisions are made. Direct questions or comments regarding Off-Label Drug Uses to jgeneral@ku.edu.

Pitfalls and Pearls in Delusional Parasitosis

“…A systematic review of multiple case series and observational studies showed a 60–100% efficacy rate with antipsychotic medications such as pimozide, olanzapine, or risperidone 11,12. Randomized controlled trials are difficult to conduct with this patient population, but some retrospective reviews note no difference between first- and second-generation antipsychotics in treatment success for delusional parasitosis 12.…”

Delusions of Parasitosis: An Update

“…In a case series of 33 patients with delusional parasitosis, 18 of them received pimozide at dosages from 1 to 5 mg/day while the other 15 patients did not take the drug. Among patients receiving pimozide, 61% achieved improvement or complete remission, while the other 39% remained unchanged [14]. Although pimozide has shown relatively good efficacy in the majority of patients, its use is significantly limited by its side effects.…”

Selection of psychotropics in dermatologic practice

“…Pimozide has been mentioned extensively as a treatment of DI; most of the supporting data come from non-randomized trials and case series/reports on the use of first-generation antipsychotics (FGAs) or secondgeneration antipsychotics (SGAs) in DI. [33,34] Pimozide has been tried for a period of 4-6 weeks with good response across trials; dosages range from 1 mg to 5 mg. [35,36] However, its use is significantly limited by side effects such as QTc prolongation and extrapyramidal symptoms. [34,37] For SGAs, there is limited evidence for their efficacy in DI; evidence is mainly from case series using relatively low doses of risperidone (1-2 mg daily) and olanzapine (2.5-5 mg daily).…”

“…[33,34] Pimozide has been tried for a period of 4-6 weeks with good response across trials; dosages range from 1 mg to 5 mg. [35,36] However, its use is significantly limited by side effects such as QTc prolongation and extrapyramidal symptoms. [34,37] For SGAs, there is limited evidence for their efficacy in DI; evidence is mainly from case series using relatively low doses of risperidone (1-2 mg daily) and olanzapine (2.5-5 mg daily). Risperidone and olanzapine have been associated with partial or full remission of DI in 69% and 72% of cases, respectively, with maximum effects being reported after at least 6 weeks of treatment.…”

“…[33] Pimozide is no longer considered to be the drug of choice due to safety concerns. [33,34,39] BDD BDD is a psychiatric disorder that is encountered more commonly in dermatologic and cosmetic surgical settings than psychiatric clinics, where patients present with one or more perceived "defects" in the appearance of their skin or hair that is slight or not observable to others. [40] While at least one-third of BDD patients have delusional BDD, the current evidence supporting the use of antipsychotics in BDD is weak.…”