Skip to main content

Drug Interactions between Equaline Acid Reducer and lapatinib

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

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

cimetidine lapatinib

Applies to: Equaline Acid Reducer (cimetidine) and lapatinib

MONITOR: Nonclinical data indicate that the solubility of lapatinib is pH-dependent. Therefore, long-term suppression of gastric acid secretion by H2-receptor antagonists or proton pump inhibitors may reduce lapatinib systemic exposure. In study subjects, coadministration with the proton pump inhibitor esomeprazole (40 mg once daily for 7 days) decreased lapatinib exposure by an average of 27% (range 6% to 49%). This effect decreases with increasing age from approximately 40 to 60 years. The clinical significance is unknown.

MANAGEMENT: Caution may be advisable if lapatinib is used in combination with H2-receptor antagonists or proton pump inhibitors. Patients should be monitored for potentially reduced therapeutic response to lapatinib.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. (2007) "Product Information. Tykerb (lapatinib)." Novartis Pharmaceuticals

Switch to consumer interaction data

Drug and food interactions

Moderate

lapatinib food

Applies to: lapatinib

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of lapatinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits.

ADJUST DOSING INTERVAL: Food can significantly increase the oral bioavailability of lapatinib. According to the manufacturer, lapatinib peak plasma concentration (Cmax) was approximately 2.5- and 3-fold higher and systemic exposure (AUC) 3- and 4-fold higher when administered with a low fat meal (5% fat; 500 calories) or with a high-fat meal (50% fat; 1000 calories), respectively, compared to fasting. Dividing the daily dose also resulted in an approximately 2-fold higher systemic exposure at steady state compared to the same total dose administered once daily.

MANAGEMENT: Patients treated with lapatinib should preferably avoid the consumption of grapefruit or grapefruit juice. The manufacturer recommends that lapatinib be administered at least one hour before or one hour after a meal. The lapatinib dose is administered once daily and should not be divided.

References

  1. (2007) "Product Information. Tykerb (lapatinib)." Novartis Pharmaceuticals

Switch to consumer interaction data

Minor

cimetidine food

Applies to: Equaline Acid Reducer (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

Switch to consumer interaction data

Minor

cimetidine food

Applies to: Equaline Acid Reducer (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

Switch to consumer interaction data

Minor

cimetidine food

Applies to: Equaline Acid Reducer (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

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