Skip to main content

Drug Interactions between Prozac Weekly and Torecan

This report displays the potential drug interactions for the following 2 drugs:

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

FLUoxetine thiethylperazine

Applies to: Prozac Weekly (fluoxetine) and Torecan (thiethylperazine)

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

  1. Stein MH "Tardive dyskinesia in a patient taking haloperidol and fluoxetine." Am J Psychiatry 148 (1991): 683
  2. Tate JL "Extrapyramidal symptoms in a patient taking haloperidol and fluoxetine." Am J Psychiatry 146 (1989): 399-400
  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
  4. "Fluoxetine and extrapyramidal side effects." Am J Psychiatry 146 (1989): 1352-3
  5. Ketai R "Interaction between fluoxetine and neuroleptics." Am J Psychiatry 150 (1993): 836-7
  6. Baldessarini RJ, Marsh E "Fluoxetine and side effects." Arch Gen Psychiatry 47 (1990): 191-2
  7. Ciraulo DA, Shader RI "Fluoxetine drug-drug interactions: I. Antidepressants and antipsychotics." J Clin Psychopharmacol 10 (1990): 48-50
  8. Lock JD, Gwirtsman HE, Targ EF "Possible adverse drug interactions between fluoxetine and other psychotropics." J Clin Psychopharmacol 10 (1990): 383-4
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
View all 13 references

Switch to consumer interaction data

Drug and food interactions

Moderate

FLUoxetine food

Applies to: Prozac Weekly (fluoxetine)

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Warrington SJ, Ankier SI, Turner P "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology 15 (1986): 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc. (1990):
  3. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  4. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 4 references

Switch to consumer interaction data

Moderate

thiethylperazine food

Applies to: Torecan (thiethylperazine)

GENERALLY AVOID: Concurrent use of ethanol and phenothiazines may result in additive CNS depression and psychomotor impairment. Also, ethanol may precipitate dystonic reactions in patients who are taking phenothiazines. The two drugs probably act on different sites in the brain, although the exact mechanism of the interaction is not known.

MANAGEMENT: Patients should be advised to avoid alcohol during phenothiazine therapy.

References

  1. Lutz EG "Neuroleptic-induced akathisia and dystonia triggered by alcohol." JAMA 236 (1976): 2422-3
  2. Freed E "Alcohol-triggered-neuroleptic-induced tremor, rigidity and dystonia." Med J Aust 2 (1981): 44-5

Switch to consumer interaction data

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

See also

Report options

Loading...
QR code containing a link to this page

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer