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Drug Interactions between Leader Heartburn Relief and Quinidex Extentabs

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

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Interactions between your drugs

Moderate

quiNIDine cimetidine

Applies to: Quinidex Extentabs (quinidine) and Leader Heartburn Relief (cimetidine)

MONITOR: Cimetidine may increase serum quinidine levels and the risk of toxicity. The mechanism may be related to decreased CYP450 hepatic metabolism or competitive inhibition of renal excretion. A case of ventricular bigeminy has been reported with ranitidine coadministration, even though it is not expected to inhibit CYP450. No data are available for other H2-antagonists.

MANAGEMENT: If patients require cimetidine or ranitidine during quinidine therapy, monitoring for clinical and laboratory evidence of quinidine toxicity is recommended. Patients should be advised to notify their physician if they experience tinnitus, hearing loss, visual disturbances, diarrhea, dizziness, weakness, headache, syncope, or rapid or irregular heartbeats.

References

  1. Farringer JA, McWay-Hess K, Clementi WA "Cimetidine-quinidine interaction." Clin Pharm 3 (1984): 81-3
  2. Iliopoulou A, Kontogiannis D, Tsoutsos D, Moulopoulos S "Quinidine-ranitidine adverse reaction." Eur Heart J 7 (1986): 360
  3. Kolb KW, Garnett WR, Small RE, Vetrovec GW, Kline BJ, Fox T "Effect of cimetidine on quinidine clearance." Ther Drug Monit 6 (1984): 306-12
  4. Hardy BG, Istvan ZT, Golden L, Lalka D, Schentag JJ "Effect of cimetidine on the pharmacokinetics pharmacodynamics of quinidine." Am J Cardiol 52 (1983): 172-5
View all 4 references

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Drug and food interactions

Moderate

quiNIDine food

Applies to: Quinidex Extentabs (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

  1. Ace LN, Jaffe JM, Kunka RL "Effect of food and an antacid on quinidine bioavailability." Biopharm Drug Dispos 4 (1983): 183-90
  2. Min DI, Ku YM, Geraets DR, Lee HC "Effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of quinidine in healthy volunteers." J Clin Pharmacol 36 (1996): 469-76
  3. Ha HR, Chen J, Leuenberger PM, Freiburghaus AU, Follah F "In vitro inhibition of midazolam and quinidine metabolism by flavonoids." Eur J Clin Pharmacol 48 (1995): 367-71
  4. 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 4 references

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Minor

cimetidine food

Applies to: Leader Heartburn Relief (cimetidine)

Concurrent use of cimetidine and ethanol may result in increased ethanol concentrations. The mechanism appears to be due to inhibition of gastric alcohol dehydrogenase by cimetidine, leading to increased bioavailability of the alcohol and inhibition of hepatic metabolism of alcohol. The clinical significance of this interaction is limited. More importantly, patients requiring cimetidine for gastrointestinal disease should be counseled to avoid alcohol to prevent worsening of their disease. The other H-2 receptor antagonists appear to have minimal effects on the concentrations of alcohol.

References

  1. Feely J, Wood AJ "Effects of cimetidine on the elimination and actions of ethanol." JAMA 247 (1982): 2819-21
  2. Hansten PD "Effects of H2-receptor antagonists on blood alcohol levels." JAMA 267 (1992): 2469

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Minor

cimetidine food

Applies to: Leader Heartburn Relief (cimetidine)

Caffeine effects may be increased in patients also taking cimetidine. The mechanism may be due to decreased caffeine metabolism induced by cimetidine. Although adequate clinical data are lacking, a reduction in dose or elimination of caffeine may be needed if excess CNS stimulation is observed.

References

  1. "Product Information. Tagamet (cimetidine)." SmithKline Beecham PROD (2001):
  2. Broughton LJ, Rodgers HJ "Decreased systenuc clearance of caffeine due to cimetidine." Br J Clin Pharmacol 12 (1981): 155-9

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Minor

cimetidine food

Applies to: Leader Heartburn Relief (cimetidine)

H2 antagonists may reduce the clearance of nicotine. Cimetidine, 600 mg given twice a day for two days, reduced clearance of an intravenous nicotine dose by 30%. Ranitidine, 300 mg given twice a day for two days, reduced clearance by 10%. The clinical significance of this interaction is not known. Patients should be monitored for increased nicotine effects when using the patches or gum for smoking cessation and dosage adjustments should be made as appropriate.

References

  1. Bendayan R, Sullivan JT, Shaw C, Frecker RC, Sellers EM "Effect of cimetidine and ranitidine on the hepatic and renal elimination of nicotine in humans." Eur J Clin Pharmacol 38 (1990): 165-9

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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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