Cimetidine (Tagamet®) was the first billion-dollar drug released back in the 1970’s for treatment of stomach ulcers. Ranitidine (Zantac®) was introduced in US market in 1983 and was the world’s biggest-selling prescription drug by 1987. It has since largely been superseded by the even more effective proton-pump inhibitors, with Prilosec (omeprazole) taking over the acid suppression market for many years.
Mechanism: this class of drugs reduce the volume and concentration of acid in gastric acid secretions.
Indications: Histamine-2 receptor antagonists (H2RA) are preferred to antacids because they are easier to take and do not slow down the bowels. Reasonably effective to treat mild/moderate gastroesophageal reflux disease (GERD). H2RA work faster than proton pump inhibitors (which may take up to 3 days). The onset of action for the H2RA’s is within one hour and lasts between 6-12 hours.
|DRUG||Year of Rx INTRO-USA||Approved OTC||Healing Dose||Prevention Dose||OTC Brand/Strength|
|1977||June 1995||800mg HS||400mg HS||Tagamet HB 200mg|
|Ranitidine (Zantac®)||1983||December 1995||300mg HS||150mg HS||Zantac 75mg, 150mg tabs|
|Famotidine (Pepcid®)||1986||April 1995||40mg HS||20mg HS||Pepcid AC-10 Pepcid AC-20|
|Nizatidine (Axid®)||1988||May 1996||300mg HS||150 HS||Axid-AR-75mg|
Patient Care points:
- All H2RA are listed a Pregnancy Category-B (no proven risk in humans). However, all packages do carry the warning to consult physician if pregnant. Do not take without consulting your physician if pregnant.
- Cimetidine (Tagamet®) : causes weak anti-androgenic effects; male breast enlargement & impotence at high doses. May cause feminization of male fetus. Even though cimetidine is Pregnancy Category-B, we don’t advise taking this drug if pregnant.
- Pepcid Complete contains: Famotidine 10 mg, Calcium carbonate 800 mg, Magnesium hydroxide 165 mg . We don’t usually don’t recommend calcium containing antacids, because the calcium will stimulate gastric acid release.
- Axid-R-75mg is not current available.
- Cimetidine (Tagamet®) does cause a fair amount of drug interactions. Have your Thompson Pharmacist scan your drug records before taking this drug. Best to avoid if you take any other medications.
- Ranitidine (Zantac) has about 10% of the drug interaction potential than that of cimetidine, so we expect insignificant drug interactions.
- Nizatidine (Axid) and famotidine (Pepcid) have no affinity for CYP450 3A4.
Always consult your Thompson Pharmacist before taking any of these potent over the counter drugs! At Thompson Pharmacy… it’s all for you!!!