Ranitidine and cimetidine belong to a group of drugs called H2 receptor antagonists. Cimetidine (Tagamet) was the first. The introduction of this drug changed the treatment of acid reflux and gastric ulcer dramatically. Surgery for gastric and duodenal ulcers are rare and operations such as Bilroth are things of the past. Today Vagotomy and Pyloropasty are only done on severe cases. In addition the information on Helicobacter pylori and ulcers means eradication cures ulcers.

H2 antagonists have a greater impact on gastric and duodenal ulcers but not as effective in acid reflux treatment. This is because a greater level of acid supression is needed. After two months on ranitidine symptom control is achieved in about 80% and maximum effect after six weeks. Larger doses improve these figures but not only are they expensive but tedious for patients. Compliance, therefore, is poor.

Success in healing of esophagitis depends on the grade of esophagitis. Overall after six weeks complete healing occurs in 50% but in grade 1 esophagitis it is 80% but severe esophagitis only 20-30%

These figures improve after longer treatment ie 3 months or more.

After proton pump inhibitors (omeprazole) were introduced, H2 antagonists were more often used if antacids were ineffective and recommended for mild forms of esophagitis (Grade 1 or 11).

Nocturnal dosing may be effective for treatment of acid reflux during the night but generally ineffective since in GERD acid supression should be over 24 hours.

Side effects are not common but these drugs can cause rashes, transient elevation of liver enzymes, and confusion in the elderly. They can increase the blood level of prolactin leading to gynaecomastia and galactorrhoea.

They can affect the efficiency of drugs such as warfarin, theophylline and phenytoin. This is more common with cimetidine and less so in ranitidine and newer H2 antagonists such as famotidine.

So for acid reflux treatment, these drugs are largly replaced by the more effective acid supressant drugs such as omeprazole.

Dr.Phil Hariram,