Drug-Drug Interaction

CARBAMAZEPINE/RISPERIDONE

MECHANISM OF ACTION
Carbamazepine may induce the metabolism of risperidone by CYP P-450-3A4.(1,2) Risperidone may inhibit the metabolism of carbamazepine.(3)

DISCUSSION
A study in 11 schizophrenic inpatients examined the effects of the addition of carbamazepine (200 mg twice daily) for one week to risperidone (3 mg twice daily). Concurrent carbamazepine decreased plasma concentrations of risperidone, 9-hydroxyrisperidone, and active moiety by 50%, 44%, and 45%, respectively.(2)

CLINICAL EFFECTS
Concurrent use may result in decreased levels and effectiveness of risperidone(1,2,4-5) and elevated levels of carbamazepine. (3)

SEVERITY LEVEL
3-Moderate Interaction: Assess the risk to the patient and take action as needed.

PATIENT MANAGEMENT
Patients receiving risperidone should be closely monitored if carbamazepine is initiated or discontinued from concurrent therapy. The dosage of risperidone may need to be adjusted.

PREDISPOSING FACTORS
None determined.

REFERENCES

  1. Risperdal Consta (risperidone long acting injection) US prescribing .Risperdal Consta (risperidone long acting injection) US prescribing information. Janssen Pharmaceutical Ltd. June, 2009.
  2. Ono S, Mihara K, Suzuki A, Kondo T, Yasui-Furukori N, Furukori H, de Vries .Ono S, Mihara K, Suzuki A, Kondo T, Yasui-Furukori N, Furukori H, de Vries R, Kaneko S. Significant pharmacokinetic interaction between risperidone and carbamazepine: its relationship with CYP2D6 genotypes. Psychopharmacology (Berl) 2002 Jun;162(1):50-4.
  3. Mula M, Monaco F. Carbamazepine-risperidone interactions in patients with .Mula M, Monaco F. Carbamazepine-risperidone interactions in patients with epilepsy. Clin Neuropharmacol 2002 Mar-Apr;25(2):97-100.
  4. Spina E, Avenoso A, Facciola G, Salemi M, Scordo MG, Giacobello T, Madia .Spina E, Avenoso A, Facciola G, Salemi M, Scordo MG, Giacobello T, Madia AG, Perucca E. Plasma concentrations of risperidone and 9-hydroxyrisperidone: effect of comedication with carbamazepine or valproate. Ther Drug Monit 2000 Aug;22(4):481-5.
  5. Spina E, Scordo MG, Avenoso A, Perucca E. Adverse drug interaction between .Spina E, Scordo MG, Avenoso A, Perucca E. Adverse drug interaction between risperidone and carbamazepine in a patient with chronic schizophrenia and deficient CYP2D6 activity. J Clin Psychopharmacol 2001 Feb;21(1):108-9.