The gram-positive bacillus Clostridium difficile is the most common identifiable cause of antibiotic-associated diarrhea and pseudomembranous colitis (R Fekety in GL Mandell et al, eds, Principles and Practice of Infectious Diseases, 3rd ed, New York:Churchill Livingstone, 1990, page 863). C. difficile colitis usually develops during or soon after antibiotic treatment. Virtually any antimicrobial agent can cause the disorder, but clindamycin, ampicillin and the cephalosporins have been implicated most frequently. Pseudomembranous colitis was recently reported in five patients who had ...

The Norplant System (Wyeth-Ayerst) for subdermal delivery of the synthetic progestin levonorgestrel was recently approved by the US Food and Drug Administration for use as a long-term contraceptive.

BCG Live (TheraCys - Connaught) and BCG Vaccine U.S.P. (TiceBCG - Organon), freeze-dried suspensions of an attenuated strain of Mycobacterium bovis, were recently approved by the US Food and Drug Administration for intravesical treatment of primary or relapsed carcinoma in situ of the bladder, with or without associated papillary tumors. BCG is not recommended for treatment of papillary tumors occurring alone.

Many drugs, mostly imidazole derivatives, are marketed in the USA for topical treatment of vulvovaginal candidiasis, and a few are now available without a prescription.

Fludarabine phosphate (Fludara - Berlex), an analog of vidarabine (Vira-A), was recently approved by the U.S. Food and Drug Administration for treatment of patients with refractory chronic lymphocytic leukemia (CLL). The drug has not yet been marketed but is still available, as it has been for two years, through the National Cancer Institute.

Pravastatin - Bristol-Myers Squibb) and simvastatin (Zocor -Merck), two new inhibitors of cholesterol synthesis similar to lovastatin (Mevacor - Merck), have now been marketed in the USA for treatment of hypercholesterolemia. Lovastatin (Medical Letter, 29:99, 1987) is the most frequently prescribed of all cholesterol-lowering drugs in the USA. Pravastatin and simvastatin were previously reviewed in The Medical Letter when they became available in Canada (volume 33, page 18, 1991).

Mycophenolate mofetil (CellCept - Roche) has been approved by the US Food and Drug Administration for oral use in preventing organ rejection in patients receiving allogeneic renal transplants. It is being promoted as an improvement over azathioprine (Imuran) for concurrent use with cyclosporine (Sandimmune; Neoral) and corticosteroids.

Valacyclovir (Valtrex - Glaxo Wellcome), an L- valyl ester of acyclovir (Zovirax), has been approved by the US Food and Drug Administration (FDA) for oral treatment of herpes zoster (shingles) in immunocompetent adults. Famciclovir (Famvir - Medical Letter, 36:97, 1994) is also available for this indication.

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.

Imiquimod (i mi kwi' mod) 5% cream (Aldara - 3M Pharmaceuticals) has been approved by the FDA for treatment of external genital and perianal warts (condyloma acuminata). The drug requires a prescription but is applied by the patient. It is the second patient-applied treatment to become available for external genital warts; the first was podofilox (Condylox - Medical Letter, 33:117, 1991).