Cimetidine vs famotidine
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Comparative Analysis of Cimetidine and Famotidine
Introduction to H2-Receptor Antagonists
Histamine H2-receptor antagonists, such as cimetidine and famotidine, are commonly used to treat gastrointestinal ulcer diseases by inhibiting gastric acid secretion. This article compares the efficacy, potency, side effects, and pharmacokinetics of cimetidine and famotidine based on recent research findings.
Efficacy and Potency in Gastric Acid Inhibition
Potency Comparison
Famotidine is significantly more potent than cimetidine. On a weight basis, famotidine is 20 times more potent than cimetidine in inhibiting basal and pentagastrin-stimulated gastric acid secretion in humans 1. Additionally, famotidine is 32 times more potent than cimetidine in controlling gastric acid hypersecretion in patients with Zollinger-Ellison syndrome 3.
Efficacy in Ulcer Treatment
Both famotidine and cimetidine are effective in treating duodenal ulcers. In a study comparing single nighttime doses, 75% of patients treated with famotidine and 77% of those treated with cimetidine were healed after four weeks 7. Another study found that famotidine provided better gastric pH control than cimetidine, making it more effective in preventing postoperative stress ulcers 5.
Side Effects and Tolerability
General Tolerability
Famotidine appears to be well tolerated and does not have the antiandrogenic effects or alter hepatic metabolism of drugs, unlike cimetidine 1. In a study involving patients with Zollinger-Ellison syndrome, famotidine showed no evidence of biochemical or hematologic toxicity over a mean treatment period of six months 3.
Impact on Drug Metabolism
Cimetidine inhibits the metabolism of many drugs by affecting the hepatic mixed-function oxidase system, leading to prolonged drug half-lives and reduced clearance. Famotidine, however, does not significantly affect the disposition of drugs like antipyrine, indicating it does not share this unwanted effect 2.
Pharmacokinetics and Renal Handling
Renal Secretion
Both cimetidine and famotidine are primarily eliminated by the kidneys. However, they exhibit different interactions with renal transporters. Famotidine is recognized and transported by human organic anion transporter 3 (hOAT3) but not by hOAT1 or hOCT2, whereas cimetidine affects multiple transport systems 4. This difference in renal handling may influence their dosing and side effect profiles in patients with renal impairment.
Competitive Inhibition
In kinetic studies, high plasma levels of cimetidine inhibit the renal excretion of famotidine, but the reverse is not true. This suggests that cimetidine has a broader impact on renal transport systems compared to famotidine 8.
Conclusion
Famotidine is a more potent and effective H2-receptor antagonist than cimetidine, with a better side effect profile and fewer interactions with drug metabolism. It provides superior gastric pH control and is well tolerated in both short-term and long-term treatments. However, the choice between these two drugs should consider individual patient needs, including renal function and potential drug interactions. Further clinical experience and studies are needed to fully understand the long-term efficacy and safety of famotidine compared to cimetidine.
Sources and full results
Most relevant research papers on this topic
Comparative effects of famotidine and cimetidine on antipyrine kinetics in healthy volunteers.
Famotidine does not significantly affect antipyrine metabolism, while cimetidine prolongs its half-life and reduces clearance by 22% in healthy volunteers.
RCTFamotidine, a new, potent, long-acting histamine H2-receptor antagonist: comparison with cimetidine and ranitidine in the treatment of Zollinger-Ellison syndrome.
Famotidine is a potent, long-acting H2-receptor antagonist that is nine times more potent than ranitidine and 32 times more potent than cimetidine, and is both safe and effective for long-term therapy of Zollinger-Ellison syndrome.
Non-RCT
Highly CitedDifferent transport properties between famotidine and cimetidine by human renal organic ion transporters (SLC22A).
Famotidine and cimetidine show distinct recognition and transport properties by human renal organic ion transporters, with hOAT3 contributing to famotidine renal tubular secretion.
In Vitro StudyComparative efficacy of cimetidine, famotidine, ranitidine, and mylanta in postoperative stress ulcers. Gastric pH control and ulcer prevention in patients undergoing coronary artery bypass graft surgery.
Famotidine or ranitidine provide better gastric pH control and prevention of postoperative stress ulcers than cimetidine or Mylanta-II in patients undergoing coronary artery bypass graft surgery.
RCTSingle night‐time doses of 40 mg famotidine or 800 mg cimetidine in the treatment of duodenal ulcer
Famotidine is effective and well-tolerated for short-term treatment of duodenal ulcers, with both drugs showing similar healing rates and well-tolerated adverse events.
RCTKinetic studies on the competition between famotidine and cimetidine in rats. Evidence of multiple renal secretory systems for organic cations.
Famotidine and cimetidine both inhibit renal secretion of TEAB but not PAH, suggesting multiple renal secretory systems for organic cations.
Non-RCT
Animal StudyEffects of histamine type 2-receptor antagonists cimetidine and famotidine on left ventricular systolic function in chronic congestive heart failure.
Standard doses of famotidine and cimetidine do not decrease left ventricular systolic function in patients with chronic congestive heart failure.
RCTDouble blind comparison of the effects of cimetidine, ranitidine, famotidine, and placebo on intragastric acidity in 30 normal volunteers.
Famotidine and ranitidine significantly reduce intragastric acidity compared to cimetidine, with famotidine showing greater reduction than ranitidine.
RCT