The US Food and Drug Administration (FDA) recently approved the marketing of clarithromycin (Biaxin - Abbott), a macrolide antibiotic, and omeprazole (Prilosec - Astra Merck), a proton pump inhibitor, for concurrent use in treatment of duodenal ulcers associated with Helicobacter pylori.

Rifaximin (Xifaxan - Salix), a non-absorbed oral antibiotic derived from rifampin (Rifadin, and others), has been approved by the FDA for treatment of travelers' diarrhea caused by noninvasive strains of Escherichia coli in patients 12 years of age or older. It has been available in Europe since 1987.

The most common cause of travelers' diarrhea, usually a self-limited illness without fever lasting several days, is infection with noninvasive enterotoxigenic (ETEC) or enteroaggregative (EAEC) strains of Escherichia coli. Campylobacter, Shigella, Salmonella, Aeromonas, viruses and parasites are less common.

About 50% of the world’s population is infected with Helicobacter pylori. These gastric bacteria can cause chronic inflammation and have been associated with development of gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Eradication of H. pylori can promote gastric healing, prevent recurrence of duodenal and gastric ulcers, and reduce the incidence of gastric cancer. Guidelines for treatment of H. pylori infection were updated recently.

Older patients are especially susceptible to drug-induced cognitive impairment. They are more likely to be taking multiple drugs, to have higher blood levels of those drugs because of renal or hepatic dysfunction, and to have pre-existing cognitive problems that make it difficult to detect the role of drugs causing new symptoms or making old ones worse.

View the Expanded Table: Drugs for Prophylaxis of Malaria

Patients who receive pretravel advice can reduce their risk for many travel-related conditions. Vaccines recommended for travelers are reviewed in a separate issue.