Skip to main content

Drug Interactions between dofetilide and terfenadine

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

Edit list (add/remove drugs)

Interactions between your drugs

Major

terfenadine dofetilide

Applies to: terfenadine and 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

Switch to consumer interaction data

Drug and food interactions

Major

terfenadine food

Applies to: terfenadine

CONTRAINDICATED: The consumption of grapefruit juice has been associated with significantly increased plasma concentrations of terfenadine. The mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits. Terfenadine in high serum levels has been associated with prolongation of the QT interval and development of torsade de pointes, a potentially fatal ventricular arrhythmia.

MANAGEMENT: Due to the risk of cardiotoxicity, patients receiving the drug should be advised to avoid consumption of grapefruit products. Loratadine, cetirizine, and fexofenadine may be safer alternatives in patients who may have trouble adhering to the dietary restriction.

References

  1. Honig PK, Woosley RL, Zamani K, Conner DP, Cantilena LR Jr "Changes in the pharmacokinetics and electrocardiographic pharmacodynamics of terfenadine with concomitant administration of erythromycin." Clin Pharmacol Ther 52 (1992): 231-8
  2. Zimmermann M, Duruz H, Guinand O, et al. "Torsades de Pointes after treatment with terfenadine and ketoconazole." Eur Heart J 13 (1992): 1002-3
  3. Mathews DR, McNutt B, Okerholm R, et al. "Torsades de pointes occurring in association with terfenadine use." JAMA 266 (1991): 2375-6
  4. Monahan BP, Ferguson CL, Killeavy ES, et al. "Torsades de pointes occurring in association with terfenadine use." JAMA 264 (1990): 2788-90
  5. Honig PK, Wortham DC, Zamani K, et al. "Terfenadine-ketoconazole interaction: pharmacokinetic and electrocardiographic consequences." JAMA 269 (1993): 1513-8
  6. Pohjola-Sintonen S, Viitasalo M, Toivonene L, Neuvonen P "Torsades de pointes after terfenadine-itraconazole interaction." BMJ 306 (1993): 186
  7. Cortese LM, Bjornson DC "Potential interaction between terfenadine and macrolide antibiotics." Clin Pharm 11 (1992): 675
  8. Paris DG, Parente TF, Bruschetta HR, Guzman E, Niarchos AP "Torsades-de-pointes induced by erythromycin and terfenadine." Am J Emerg Med 12 (1994): 636-8
  9. Zechnich AD, Haxby DG "Drug interactions associated with terfenadine and related nonsedating antihistamines." West J Med 164 (1996): 68-9
  10. Honig PK, Wortham DC, Lazarev A, Cantilena LR "Grapefruit juice alters the systemic bioavailability and cardiac repolarization of terfenadine in poor metabolizers of terfenadine." J Clin Pharmacol 36 (1996): 345-51
  11. Woosley RL "Cardiac actions of antihistamines." Annu Rev Pharmacol Toxicol 36 (1996): 233-52
  12. Benton RE, Honig PK, Zamani K, Cantilena LR, Woosley RL "Grapefruit juice alters terfenadine pharmacokinetics resulting in prolongation of repolarization on the electrocardiogram." Clin Pharmacol Ther 59 (1996): 383-8
  13. Hsieh MH, Chen SA, Chiang CE, et al. "Drug-induced torsades de pointes in one patient with congenital long QT syndrome." Int J Cardiol 54 (1996): 85-8
  14. Clifford CP, Adams DA, Murray S, Taylor GW, Wilkins MR, Boobis AR, Davies DS "Pharmacokinetic and cardiac effects of terfenadine after inhibition of its metabolism by grapefruit juice." Br J Clin Pharmacol 42 (1996): p662
  15. Rau SE, Bend JR, Arnold JMO, Tran LT, Spence JD, Bailey DG "Grapefruit juice terfenadine single-dose interaction: Magnitude, mechanism, and relevance." Clin Pharmacol Ther 61 (1997): 401-9
  16. Bailey DG, Malcolm J, Arnold O, Spence JD "Grapefruit juice-drug interactions." Br J Clin Pharmacol 46 (1998): 101-10
  17. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther 68 (2000): 468-77
View all 17 references

Switch to consumer interaction data

Minor

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

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

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