The FDA recently approved three new drugs for treatment of hyperlipidemia. Ezetimibe (ez et' i mibe; Zetia) is the first in a new class of drugs that inhibit intestinal absorption of cholesterol. Extended-release lovastatin (Altocor) is a new formulation of lovastatin (Mevacor, and others). Extended-release niacin plus (immediate-release) lovastatin (Advicor) is the first fixed-dose combination of lipid-lowering drugs.

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.

Atazanavir (Reyataz - Bristol-Myers Squibb), a new protease inhibitor (PI), and emtricitabine (Emtriva - Gilead), a nucleoside analogue reverse transcriptase inhibitor (NRTI) chemically similar to lamivudine, have been approved by the FDA for treatment of HIV-1 infection. Both are taken once daily, unlike most anti-HIV drugs.

The ability of grapefruit juice to increase serum concentrations of drugs was first discovered during a study of the effect of ethanol on felodipine (Plendil) pharmacokinetics. Double-strength grapefruit juice used to disguise the taste of ethanol resulted in higher than expected serum concentrations of felodipine (DG Bailey et al, Clin Invest Med 1989; 12:357).

Cetuximab (Erbitux - ImClone Systems/Bristol-Myers Squibb), an epidermal growth factor receptor (EGFR) inhibitor, and bevacizumab (Avastin - Genentech), the first vascular endothelial growth factor angiogenesis inhibitor, have recently been approved by the FDA for treatment of patients with metastatic colorectal cancer. Cetuximab is approved for treatment of patients with EGFR-expressing tumors, either in combination regimens with irinotecan (Camptosar)when the cancer has progressed on irinotecan-based therapy, or as monotherapy for those who cannot tolerate irinotecan. Bevacizumab is approved...

Tinidazole (Tindamax - Presutti Labs), an oral antiprotozoal drug similar to metronidazole (Flagyl, and others), has been approved by the FDA for treatment of trichomoniasis in adults and for treatment of giardiasis, intestinal amebiasis and amebic liver abcess in adults and children more than 3 years old. Tinidazole has been widely used outside of the US for decades under the trade name Fasigyn (Pfizer).

The FDA has approved two new drugs for treatment of previously-treated unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer: fam-trastuzumab deruxtecannxki (Enhertu – Daiichi-Sankyo/AstraZeneca), an IV HER2-directed monoclonal antibody linked to the topoisomerase I inhibitor DXd, and tucatinib (Tukysa – Seagen), an oral tyrosine kinase inhibitor.

The US Food and Drug Administration (FDA) recently approved a stronger warning about hepatotoxicity in the labeling for chlorzoxazone, a centrally-acting skeletal muscle relaxant.

Four different desk-top systems are now widely used in physicians'; offices to measure blood chemistries. The Ektachem DT (Kodak) and Reflotron (Boehringer Mannheim), reviewed previously in The Medical Letter (volume 30, page 119, 1988; volume 31, page 90, 1989), resemble the Seralyzer (Miles Diagnostics) in cost; the Vision (Abbott), which is fully automated, is much more expensive.

Ciprofloxacin, previously available orally (Cipro - Medical Letter, 30:11, 1988) and for ophthalmic use (Ciloxan - Medical Letter, 33:52, May 31, 1991), is now the first fluoroquinolone antibiotic to become available in the USA in an intravenous (IV) formulation. Cipro I.V. (Miles) is being promoted as an alternative to third-generation cephalosporins, aminoglycosides, and other drugs used for treatment of serious infections.