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Prozac and Risperdal

Determining the interaction of Prozac and Risperdal and the possibility of their joint administration.

Check result:

Prozac <> Risperdal

Relevance: 14.03.2023 Reviewer: Shkutko P.M., M.D., in

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Consumer:

FLUoxetine may increase the blood levels and effects of risperiDONE. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Professional:

MONITOR: Coadministration with fluoxetine may increase the plasma concentrations of certain neuroleptic agents and potentiate the risk of extrapyramidal adverse effects. The proposed mechanism is inhibition of CYP450 2D6 metabolism by fluoxetine and its active metabolite, norfluoxetine. In 10 psychiatric patients stabilized on risperidone therapy (4 to 6 mg/day), the addition of fluoxetine (20 mg/day) led to a mean 4-fold increase in plasma risperidone concentrations and a 75% increase in levels of active moiety (i.e. sum of the concentrations of risperidone and its active 9-hydroxy metabolite). One patient developed severe akathisia and two developed Parkinsonian symptoms within the first two weeks. In contrast, mean plasma concentrations of haloperidol were elevated by just 20% following the addition of fluoxetine (20 mg/day for 7 to 10 days) in eight psychotic patients stabilized on haloperidol, and extrapyramidal side effects did not increase appreciably. However, haloperidol has been implicated clinically in various case reports, as has the phenothiazine fluphenazine. Some believe that a pharmacodynamic interaction may be partially responsible, as fluoxetine alone has been associated with extrapyramidal symptoms, possibly due to serotonergic inhibition of nigrostriatal dopaminergic pathways.

MANAGEMENT: Caution is recommended if fluoxetine is prescribed with phenothiazines or other neuroleptic agents that are thought to be metabolized by CYP450 2D6. Plasma neuroleptic levels and pharmacologic effects should be closely monitored and the dosage(s) adjusted accordingly, particularly following initiation or discontinuation of fluoxetine in patients who are stabilized on their neuroleptic regimen. Patients should be advised to contact their physician if they develop extrapyramidal symptoms such as tremor, shuffling gait, drooling, a mask-like face, tongue stiffness, muscle spasms or rigidity, and involuntary movements. Due to the long half-life of fluoxetine and norfluoxetine, the risk of an interaction may exist for an extended period (up to several weeks) after discontinuation of fluoxetine.

References

Dsouza DC, Bennett A, Abidargham A, Krystal JH "Precipitation of a psychoneuromotor syndrome by fluoxetine in a haloperidol-treated schizophrenic patient." J Clin Psychopharmacol 14 (1994): 361-3
Goff DC, Midha KK, Brotman AW, Waites M, Baldessarini RJ "Elevation of plasma concentrations of haloperidol after the addition of fluoxetine." Am J Psychiatry 148 (1991): 790-2
"Fluoxetine and extrapyramidal side effects." Am J Psychiatry 146 (1989): 1352-3
Spina E, Avenoso A, Scordo MG, et al. "Inhibition of Risperidone Metabolism by Fluoxetine in Patients With Schizophrenia: A Clinically Relevant Pharmacokinetic Drug Interaction." J Clin Psychopharmacol 22 (2002): 419-423
Tyndale RF, Kalow W, Inaba T "Oxidation of reduced haloperidol to haloperidol: involvement of human P450IID6 (sparteine/debrisoquine monooxygenase)." Br J Clin Pharmacol 31 (1991): 655-60
Ketai R "Interaction between fluoxetine and neuroleptics." Am J Psychiatry 150 (1993): 836-7
Tate JL "Extrapyramidal symptoms in a patient taking haloperidol and fluoxetine." Am J Psychiatry 146 (1989): 399-400
Avenoso A, Spina E, Campo G, Facciola G, Ferlito M, Zuccaro P, Perucca E, Caputi AP "Interaction between fluoxetine and haloperidol: Pharmacokinetic and clinical implications." Pharmacol Res 35 (1997): 335-9
Ciraulo DA, Shader RI "Fluoxetine drug-drug interactions: I. Antidepressants and antipsychotics." J Clin Psychopharmacol 10 (1990): 48-50
Stein MH "Tardive dyskinesia in a patient taking haloperidol and fluoxetine." Am J Psychiatry 148 (1991): 683
Lock JD, Gwirtsman HE, Targ EF "Possible adverse drug interactions between fluoxetine and other psychotropics." J Clin Psychopharmacol 10 (1990): 383-4
Baldessarini RJ, Marsh E "Fluoxetine and side effects." Arch Gen Psychiatry 47 (1990): 191-2
Bork JA, Rogers T, Wedlund PJ, deLeon J "A pilot study on risperidone metabolism: The role of cytochromes P450 2D6 and 3A." J Clin Psychiatry 60 (1999): 469-76

Prozac

Generic Name: fluoxetine

Brand name: Prozac, Prozac Weekly, Sarafem, Rapiflux, Selfemra, PROzac Pulvules

Synonyms: Prozac Capsules

What is Prozac?

Risperdal

Generic Name: risperidone

Brand name: Risperdal, Perseris, Risperdal Consta, Risperdal Consta, Risperdal M-Tab

Synonyms: n.a.

What is Risperdal?

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In the course of checking the drug compatibility and interactions, data from the following reference sources was used: Drugs.com, Rxlist.com, Webmd.com, Medscape.com.

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