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Drug Interactions between Permitil and Tikosyn

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

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Interactions between your drugs

Major

fluPHENAZine dofetilide

Applies to: Permitil (fluphenazine) and Tikosyn (dofetilide)

GENERALLY AVOID: Like other class III antiarrhythmic agents, dofetilide can cause dose-related QT interval prolongation. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s).

MANAGEMENT: Coadministration of dofetilide with other drugs that can prolong the QT interval has not been studied and is not recommended.

References

  1. "Product Information. Tikosyn (dofetilide)." Pfizer U.S. Pharmaceuticals PROD (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Canadian Pharmacists Association "e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink" (2006):
  4. Cerner Multum, Inc. "Australian Product Information." O 0
View all 4 references

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Drug and food interactions

Moderate

fluPHENAZine food

Applies to: Permitil (fluphenazine)

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

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Minor

dofetilide food

Applies to: Tikosyn (dofetilide)

In vitro data suggest that grapefruit juice may inhibit the CYP450 3A4 first-pass metabolism of dofetilide. Decreased first-pass metabolism may increase dofetilide concentrations and increase the risk of QT interval prolongation and arrhythmias. The clinical significance is unknown, since dofetilide has a high oral bioavailability and a low affinity for CYP450 3A4. The manufacturer recommends caution.

References

  1. "Product Information. Tikosyn (dofetilide)." Pfizer U.S. Pharmaceuticals PROD (2001):

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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

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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.

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