Medical Health Encyclopedia

Side Effects of Antibiotics.

• The most common side effects of nearly all antibiotics are gastrointestinal problems, including cramps, nausea, vomiting, and diarrhea.
• Allergic reactions can also occur with all antibiotics but are most common with medications derived from penicillin or sulfa. These reactions can range from mild skin rashes to rare but severe, even life-threatening anaphylactic shock.
• Some drugs, including certain over-the-counter medications, interact with antibiotics; patients should report to the doctor all medications they are taking.
• They double the risk for vaginal infections in women.

Bismuth

Compounds that contain bismuth are often used in the three-drug antibiotic regimens. They destroy the cell walls of the H. pylori bacteria. The only bismuth compound available in the US has been bismuth subsalicylate (Pepto-Bismol), although a drug combination of the H2 blocker ranitidine and bismuth citrate (Tritec) has been released. High doses can cause vomiting and depression of the central nervous system, but the doses given for ulcer patients rarely cause side effects.

H2 Blockers

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H2 blockers impede acid production by blocking the actions of histamine, a substance produced by the body that encourages acid secretion in the stomach. H2 blockers were the standard treatment for peptic ulcers until the development of antibiotic regimens against H. pylori. These drugs cannot cure ulcers, but in certain cases they are useful. They are effective only for duodenal ulcers, however, and have little effect on stomach (gastric) ulcers. Four H2 blockers are currently available over the counter in the US: famotidine (Pepcid AC), cimetidine (Tagamet), ranitidine (Zantac), and nizatidine (Axid). All have good safety profiles and few side effects. Each is discussed below. H2 blockers can interact with other drugs, so the doctor should be made aware of any other drugs a patient is taking. There are some differences among these drugs.