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

The FDA has approved rolapitant (Varubi – Tesaro), an oral substance P/neurokinin 1 (NK₁) receptor antagonist, for use with other antiemetics to prevent delayed nausea and vomiting associated with cancer chemotherapy in adults. It is the third substance P/NK₁ receptor antagonist to be approved in the US; aprepitant (Emend) and netupitant (only available in combination with the 5-HT₃ receptor antagonist palonosetron as Akynzeo) were approved earlier for prevention of both acute and delayed chemotherapy-induced nausea and vomiting.

Patients planning to travel to other countries often ask for information about prevention of diarrhea, malaria, and other travel-related conditions. Vaccines recommended for travelers based on their destination, length of stay, and planned activities were reviewed in a previous issue.

The text below reviews some common bacterial infections and their treatment. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Patients planning to travel to other countries often ask physicians for information about appropriate vaccines and prevention of diarrhea and malaria. Guidelines are also available from the Infectious Diseases Society of America (IDSA).

Information about empirical treatment of bacterial infections, emerging trends in antimicrobial resistance, new drugs and new data about older drugs continue to become available. Usual pathogens and empiric treatment for some common types of infections are summarized in the text and a table listing the drugs of choice and alternatives for each pathogen begins on page 40. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Patients planning to travel to other countries often ask physicians for information about immunizations and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control and Prevention at 877-FYI-TRIP (877-394-8747) or www.cdc.gov/travel.

Patients planning to travel to other countries often ask physicians for advice about immunizations and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control (CDC) at 877-FYI-TRIP (877-394-8747) or www.cdc.gov/travel. Recommendations for the treatment of parasitic diseases are available in the public reading room of The Medical Letter's web site.

Palonosetron (Aloxi - Helsinn Healthcare SA, Switzerland, distributed in the US by MGI Pharma) is the fourth serotonin (5-HT₃) receptor antagonist to become available in the US and the first to be approved by the FDA for prevention of both acute and delayed nausea and vomiting due to moderately emetogenic cancer chemotherapy. It is also approved for prevention of acute nausea and vomiting due to highly emetogenic drugs such as cisplatin (Platinol, and others). Aprepitant (Emend), a substance P/neurokinin-1 receptor antagonist, was approved last year for use with a 5-HT₃ antagonist and dexamethasone to prevent both acute and delayed nausea and vomiting due to highly emetogenic drugs (Medical Letter 2003; 45:62).

New drugs for bacterial infections and new information about older drugs continue to become available. Empirical treatment of some common bacterial infections is discussed in this article. A table listing the drugs of choice and alternatives for each pathogen begins on page 18. These recommendations are based on results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants. Local resistance patterns should be taken into account. Trade names are listed on page 24.

Aprepitant (Emend - Merck), the first substance P/neurokinin 1 (NK₁) receptor antagonist to be approved by the FDA, is now available for oral use with corticosteroids and selective serotonin (5-HT₃) receptor antagonists to prevent nausea and vomiting caused by highly emetogenic anticancer drugs such as cisplatin.

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

Dolasetron (Anzemet - Hoechst Marion Roussel), a selective serotonin (5-HT₃) receptor antagonist similar to ondansetron (Zofran) and granisetron (Kytril - Medical Letter, 36:61, 1994) is now available for both oral and intravenous use in prevention of nausea and vomiting due to cancer chemotherapy. A 5-HT₃ antagonist plus dexamethasone (Decadron, and others) is the most effective regimen for prevention of acute vomiting caused by cancer chemotherapy. Dolasetron has also been approved by the FDA for prevention and treatment of postoperative nausea and vomiting.

Several currently available antiemetic drugs can prevent vomiting caused by cancer chemotherapy. Anticancer drugs that cause vomiting are listed in the table below.

Paclitaxel (Taxol - Bristol-Myers Squibb) is now available in the USA for treatment of metastatic ovarian cancer refractory to other drugs. The new drug is a natural product extracted in small amounts from the inner bark of the Western yew tree found mainly in the Pacific northwest (Taxus brevifolia). Efforts to synthesize the drug have been unsuccessful to date, but a semi-synthetic product (taxotere) prepared from the needles of European yews has shown some promise (R Pazdur et al, J Natl Cancer Inst, 89:1781, 1992), and a fungus (Taxomyces andreanae) growing on the Pacific yew was recently found to produce paclitaxel even after removal from the tree (A Stierle et al, Science, 260:214, April 9, 1993). In any case, supply of the drug is currently keeping up with demand.

Rapid exposure to altitudes more than 8,000 feet above sea level can cause serious medical problems. Since the last Medical Letter article on this subject (Vol. 30, page 89, 1988), some new information on prevention and treatment of these disorders has been reported.

An intranasal formulation of the corticosteroid triamcinolone (Nasacort - Rh ne- Poulenc Rorer) was recently approved by the US Food and Drug Administration for once-daily treatment of seasonal and perennial allergic rhinitis.

Ondansetron (on dan' se tron; Zofran - Glaxo), a serotonin (5-hydroxytryptamine) antagonist, was recently marketed in the USA for intravenous use to prevent nausea and vomiting due to cancer chemotherapy. An oral formulation is available in many other countries.

A recent report in the New England Journal of Medicine suggested that in children with bacterial meningitis, adding the corticosteroid dexamethasone (Decadron; and others) to antibiotic treatment could decrease the incidence of moderate or severe hearing loss.

Rapid exposure to altitudes more than 8,000 feet above sea level can cause serious medical problems. Some new approaches to prevention and treatment of these disorders have recently been reported.