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Drug Interactions between Aralen Phosphate and Leader Heartburn Relief

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

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Interactions between your drugs

Moderate

chloroquine cimetidine

Applies to: Aralen Phosphate (chloroquine) and Leader Heartburn Relief (cimetidine)

GENERALLY AVOID: Coadministration with cimetidine may increase the plasma concentrations of chloroquine. The proposed mechanism is cimetidine inhibition of chloroquine metabolism via hepatic microsomal enzymes. In five healthy volunteers, administration of a single 600 mg dose of chloroquine base in combination with cimetidine (400 mg at bedtime for four days) resulted in a 53% decrease in the apparent oral clearance of chloroquine, a 49% increase in its elimination half-life, and a 57% increase in apparent volume of distribution compared to five healthy volunteers given chloroquine alone. There was also a 47% reduction in systemic exposure to the major metabolite, monodesethylchloroquine, in cimetidine-treated subjects relative to controls. Another study performed by the same group of investigators found no significant interaction with ranitidine.

MANAGEMENT: Concomitant use of chloroquine and cimetidine should be avoided. Other H2-receptor antagonists such as famotidine, nizatidine, and ranitidine may be considered during chloroquine treatment, since they are not known to interfere with cytochrome P450 isoenzymes to any significant extent. The same precaution may be applicable to hydroxychloroquine, although no data are available to support this recommendation.

References

  1. Ette EI, Brown-Awala EA, Essien EE (1987) "Chloroquine elimination in humans: effect of low-dose cimetidine." J Clin Pharmacol, 27, p. 813-6
  2. Ette EI, Brown-Awala EA, Essien EE (1987) "Effect of ranitidine on chloroquine disposition." Drug Intell Clin Pharm, 21, p. 732-4
  3. (2002) "Product Information. Aralen (chloroquine)." Sanofi Winthrop Pharmaceuticals
  4. Haagsma CJ (1998) "Clinically important drug interactions with disease-modifying antirheumatic drugs." Drugs Aging, 13, p. 281-9
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics."
View all 5 references

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Drug and food interactions

Moderate

chloroquine food

Applies to: Aralen Phosphate (chloroquine)

GENERALLY AVOID: Theoretically, grapefruit and grapefruit juice may increase the plasma concentrations of hydroxychloroquine or chloroquine and the risk of toxicities such as QT interval prolongation and ventricular arrhythmias. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruit. Following coadministration with cimetidine, a weak to moderate CYP450 3A4 inhibitor, a 2-fold increase in chloroquine exposure occurred. Since chloroquine and hydroxychloroquine have similar structures and metabolic elimination pathways, a similar interaction may be observed with hydroxychloroquine. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Although clinical data are lacking, it may be advisable to avoid the consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract during hydroxychloroquine or chloroquine therapy.

References

  1. Cerner Multum, Inc. "Australian Product Information."

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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 (1982) "Effects of cimetidine on the elimination and actions of ethanol." JAMA, 247, p. 2819-21
  2. Hansten PD (1992) "Effects of H2-receptor antagonists on blood alcohol levels." JAMA, 267, p. 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. (2001) "Product Information. Tagamet (cimetidine)." SmithKline Beecham
  2. Broughton LJ, Rodgers HJ (1981) "Decreased systenuc clearance of caffeine due to cimetidine." Br J Clin Pharmacol, 12, p. 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 (1990) "Effect of cimetidine and ranitidine on the hepatic and renal elimination of nicotine in humans." Eur J Clin Pharmacol, 38, p. 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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