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Drug Interactions between Eulexin and quinidine

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

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Interactions between your drugs

Major

quiNIDine flutamide

Applies to: quinidine and Eulexin (flutamide)

GENERALLY AVOID: Class IA (e.g., disopyramide, quinidine, procainamide) and class III (e.g., amiodarone, dofetilide, sotalol) antiarrhythmic agents can cause dose-related prolongation of the QT interval. 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 class IA or class III antiarrhythmic agents with other drugs that can prolong the QT interval should preferably be avoided unless benefits are anticipated to outweigh the risks. Caution and clinical monitoring are recommended if concomitant use is required. Patients should be advised 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 (13)
  1. (2002) "Product Information. Cordarone (amiodarone)." Wyeth-Ayerst Laboratories
  2. (2002) "Product Information. Vascor (bepridil)." McNeil Pharmaceutical
  3. (2001) "Product Information. Procan SR (procainamide)." Parke-Davis
  4. "Product Information. Quiniglute (quinidine)." Berlex, Richmond, CA.
  5. (2001) "Product Information. Betapace (sotalol)." Berlex Laboratories
  6. (2001) "Product Information. Norpace (disopyramide)." Searle
  7. Trujillo TC, Nolan PE (2000) "Antiarrhythmic agents - Drug interactions of clinical significance." Drug Safety, 23, p. 509-32
  8. Yamreudeewong W, DeBisschop M, Martin L, Lower D (2003) "Potentially Significant Drug Interactions of Class III Antiarrhythmic Drugs." Drug Saf, 26, p. 421-38
  9. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  10. Canadian Pharmacists Association (2006) e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink
  11. Cerner Multum, Inc. "Australian Product Information."
  12. EMA. European Medicines Agency. European Union (2013) EMA - List of medicines under additional monitoring. http://www.ema.europa.eu/ema/index.jsp?curl=pages/regulation/document_listing/document_listing_000366.jsp&mid=WC0b01ac058067c852
  13. Maxa JL, Hebeler RF, Adeeko MA (2006) "Torsades de pointes following concurrent amiodarone and levofloxacin therapy." Proc (Bayl Univ Med Cent), 19, p. 345-6

Drug and food interactions

Moderate

quiNIDine food

Applies to: quinidine

GENERALLY AVOID: In a small, randomized, crossover study, the administration of quinidine with grapefruit juice (compared to water) to healthy volunteers significantly prolonged the time to reach peak plasma quinidine concentrations and decreased the plasma concentrations of its major metabolite, 3-hydroxyquinidine. These changes were associated pharmacodynamically with both a delay and a reduction in the maximal effect on QTc interval. The proposed mechanism is delay of gastric emptying as well as inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.

MANAGEMENT: Given the drug's narrow therapeutic index, patients receiving quinidine therapy should avoid the consumption of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels.

References (4)
  1. Ace LN, Jaffe JM, Kunka RL (1983) "Effect of food and an antacid on quinidine bioavailability." Biopharm Drug Dispos, 4, p. 183-90
  2. Min DI, Ku YM, Geraets DR, Lee HC (1996) "Effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of quinidine in healthy volunteers." J Clin Pharmacol, 36, p. 469-76
  3. Ha HR, Chen J, Leuenberger PM, Freiburghaus AU, Follah F (1995) "In vitro inhibition of midazolam and quinidine metabolism by flavonoids." Eur J Clin Pharmacol, 48, p. 367-71
  4. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR (2000) "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther, 68, p. 468-77
Moderate

flutamide food

Applies to: Eulexin (flutamide)

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.

References (4)
  1. (2024) "Product Information. Cytisine (cytisinicline)." Consilient Health Ltd
  2. jeong sh, Newcombe D, sheridan j, Tingle M (2015) "Pharmacokinetics of cytisine, an a4 b2 nicotinic receptor partial agonist, in healthy smokers following a single dose." Drug Test Anal, 7, p. 475-82
  3. Vaughan DP, Beckett AH, Robbie DS (1976) "The influence of smoking on the intersubject variation in pentazocine elimination." Br J Clin Pharmacol, 3, p. 279-83
  4. Zevin S, Benowitz NL (1999) "Drug interactions with tobacco smoking: an update" Clin Pharmacokinet, 36, p. 425-38

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.

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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

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