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Drug Interactions between Pepcid AC Chewable Tablets and Vitamin B12

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

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Interactions between your drugs

Minor

famotidine cyanocobalamin

Applies to: Pepcid AC Chewable Tablets (famotidine) and Vitamin B12 (cyanocobalamin)

By reducing or suppressing gastric acid secretion, H2-receptor antagonists and proton pump inhibitors may interfere with the gastrointestinal absorption of vitamin B12, a process that is dependent on the presence of gastric acid and pepsin. Clinical studies have shown that dietary (i.e., protein-bound) vitamin B12 malabsorption can occur during treatment with these agents, particularly proton pump inhibitors, although the likelihood of developing clinically significant deficiency over time is unknown. There has been one reported case of vitamin B12 deficiency with megaloblastic anemia in a patient who received omeprazole at a minimum of 40 mg/day for 4 years. Also uncertain is whether acid reduction or suppression can affect the absorption of vitamin B12 ingested in the form of oral supplements such as cyanocobalamin. Non-oral routes of administration (e.g., parenteral, intranasal, sublingual) are generally preferred in the treatment of B12 deficiency-related anemia.

References (5)
  1. Salom IL, Silvis SE, Doscherholmen A (1982) "Effect of cimetidine on the absorption of vitamin B12." Scand J Gastroenterol, 17, p. 129-31
  2. Marcuard SP, Albernaz L, Khazanie PG (1994) "Omeprazole therapy causes malabsorption of cyanocobalamin (vitamin-b12)." Ann Intern Med, 120, p. 211-5
  3. Lavy NW (1994) "Omeprazole and vitamin B12." Ann Intern Med, 121, p. 74
  4. Dutta SK (1994) "Vitamin b-12 malabsorption and omeprazole therapy." J Am Coll Nutr, 13, p. 544-5
  5. Bradford GS, Taylor CT (1999) "Omeprazole and vitamin B-12 deficiency." Ann Pharmacother, 33, p. 641-3

Drug and food interactions

Minor

famotidine food

Applies to: Pepcid AC Chewable Tablets (famotidine)

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)
  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

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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