Drug Interactions between dofetilide and Vanamine PD
This report displays the potential drug interactions for the following 2 drugs:
- dofetilide
- Vanamine PD (diphenhydramine)
Interactions between your drugs
diphenhydrAMINE dofetilide
Applies to: Vanamine PD (diphenhydramine) and dofetilide
GENERALLY AVOID: The use of higher than recommended dosages of diphenhydramine (e.g., through abuse or misuse) has been associated with serious and potentially fatal cardiac adverse events, including cardiac arrest, and arrhythmia related to prolongation of the QT interval. Coadministration with class Ia (e.g., disopyramide, quinidine, procainamide) and class III (e.g., amiodarone, dofetilide, sotalol) antiarrhythmic agents 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: Australian authorities recommend avoiding concomitant use of diphenhydramine and class Ia or class III antiarrhythmic agents. Additionally, patients should be counseled to not exceed the recommended dosage and frequency or duration of use of diphenhydramine, and to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.
References
- Cerner Multum, Inc. "Australian Product Information."
- Shah A, Yousuf T, Ziffra J, Zaidi A, Raghuvir R (2015) "Diphenhydramine and QT prolongation - A rare cardiac side effect of a drug used in common practice." J Cardiol Cases, 12, p. 126-9
- Husain Z, Hussain K, Nair R, Steinman R (2010) "Diphenhydramine induced QT prolongation and torsade de pointes: An uncommon effect of a common drug." Cardiology, 17, p. 509-11
- Poluzzi E, Raschi E, Godman B, et al. (2014) "Pro-arrhythmic potential of oral antihistamines (H1): Combining adverse event reports with drug utilization data across Europe." PLoS One, 10, epub
Drug and food interactions
diphenhydrAMINE food
Applies to: Vanamine PD (diphenhydramine)
GENERALLY AVOID: Use of anticholinergic agents with alcohol may result in sufficient impairment of attention so as to render driving and operating machinery more hazardous. In addition, the potential for abuse may be increased with the combination. The mechanism of interaction is not established but may involve additive depressant effects on the central nervous system. No effect of oral propantheline or atropine on blood alcohol levels was observed in healthy volunteers when administered before ingestion of a standard ethanol load. However, one study found impairment of attention in subjects given atropine 0.5 mg or glycopyrrolate 1 mg in combination with alcohol.
MANAGEMENT: Alcohol should generally be avoided during therapy with anticholinergic agents. Patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.
References
- Linnoila M (1973) "Drug effects on psychomotor skills related to driving: interaction of atropine, glycopyrrhonium and alcohol." Eur J Clin Pharmacol, 6, p. 107-12
dofetilide food
Applies to: 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
- (2001) "Product Information. Tikosyn (dofetilide)." Pfizer U.S. Pharmaceuticals
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
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
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. | |
No interaction information available. |
Further information
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