Soon after The Medical Letter first reviewed use of natalizumab (Tysabri – Biogen Idec and Elan) for treatment of relapsing forms of multiple sclerosis (MS) (Med Lett Drugs Ther 2005; 47:13), the drug was withdrawn from the market. The unpublished clinical trials that led to its approval by the FDA have since been published, and now the drug has been returned to the market with prescribing restrictions.Natalizumab decreases the number of relapses and new brain lesions in patients with MS. It was withdrawn because progressive multifocal leukoencephalopathy (PML) occurred in 3 (of about 3000)...

The FDA recently advised health care professionals and consumers not to use a number of dietary supplements found to contain the phosphodiesterase-5 inhibitor sildenafil (Viagra) or an analog of the drug (www.fda.gov). Although the effects of sildenafil may be noticeable (in men), the presence of other, possibly more toxic adulterants in dietary supplements may be more difficult or impossible to detect.Other drugs previously found in dietary supplements have included lovastatin (Mevacor, and others), estrogen, alprazolam (Xanax, and others), indomethacin (Indocin, and others) and warfarin...

Colesevelam (Welchol - Daiichi Sankyo - Med Lett Drugs Ther 2000; 42:102), a bile-acid sequestrant used to lower LDL cholesterol, has been approved by the FDA as an adjunct to diet and exercise in the treatment of type 2 diabetes. In unpublished studies summarized in the package insert, patients with type 2 diabetes taking metformin (Glucophage, and others), a sulfonylurea or insulin (each as either monotherapy or in combination with other anti-diabetic agents) were given colesevelam 3800 mg per day or placebo; colesevelam significantly reduced glycosylated hemoglobin (A1c) by about 0.5% more...

The May 5, 2008 article (Med Lett Drugs Ther 2008; 50:34) on the approval of natalizumab (Tysabri) for treatment of Crohn's disease in the "Adverse Effects" section on page 35 included the statement: "post-marketing hepatotoxicity, sometimes fatal or requiring liver transplantation, has occurred." Actually, no fatal hepatotoxicity or liver transplantation has been reported to date. The FDA warning about post-marketing hepatotoxicity with Tysabri that was the basis for our statement said: "The combination of transaminase elevations and elevated bilirubin without evidence of obstruction is...

The Medical Letter was founded in 1959 by Arthur Kallet, an engineer, and Dr. Harold Aaron, an internist. In 1932, Kallet had written the book 100,000,000 Guinea Pigs, a best-seller that was partly responsible for the Food and Drug Act of 1938, which required for the first time that new drugs show proof of safety. He was the founding director of Consumers Union and started the publication of Consumer Reports. Dr. Aaron, who became the medical director of Consumer Reports, suggested to Kallet that doctors could use a similar publication to evaluate the new drugs that were coming on the market...

(Med Lett Drugs Ther 2009; 51:25) In the paragraph on dosing, the second-to-last sentence should have said that the new recommendations suggest considering use of an alternative antibiotic when the MIC for the infecting organism is ≥2 mg/L, not >2 mg/L.

View Table 3: Some Drug Interactions with DAAs for HCV Infection

Immune-mediated hemolysis is a rare adverse effect of second- and third-generation cephalosporins, especially cefotetan (Cefotan) (PA Arndt et al, Transfusion 1999; 39:1239). A recent report serves as a reminder that life-threatening immune-mediated hemolysis rarely can follow administration of ceftriaxone (Rocephin), one of the most commonly used parenteral antibiotics in the US (A Citak et al, J Paediatr Child Health 2002; 38:209).

A cyclosporine 0.05% ophthalmic emulsion (Restasis - Allergan) has been approved by the FDA for use in patients with dry eye disease (keratoconjunctivitis sicca). This review begins with a discussion of the causes of dry eye disease and includes sections on the pharmacology, adverse effects and clinical trial results for ophthalmic cyclosporine. Cost information and recommendations for administering the drug are also presented. The review concludes with an overall assessment of the drug's efficacy, safety and cost.

Atomoxetine (Strattera - Lilly), a nonstimulant drug that is not a controlled substance, was approved by the FDA in early 2003 for the treatment of attention deficit hyperactivity disorder (ADHD). At that time, The Medical Letter concluded that it was unclear whether atomoxetine was as effective as stimulants such as methylphenidate (Concerta, and others) (Medical Letter 2003; 45:11). Since then, the drug has been heavily advertised directly to the public for use in both children and...