A live attenuated varicella-zoster vaccine (Zostavax - Merck) has been approved by the FDA for prevention of herpes zoster (HZ; zoster; shingles) in persons ≥60 years old. Each dose of Zostavax contains about 14 times as much varicella-zoster virus (VZV) as Varivax, which has been used in the US since 1995 to vaccinate against varicella (chicken pox).

Darunavir (Prezista - Tibotec), a new protease inhibitor, has received accelerated approval from the FDA for use in combination therapy of human-immunodeficiency virus (HIV) infection in previously treated adults. It is coadministered with low-dose ritonavir (Norvir), which increases its bioavailability.

Statins have been shown to reduce the risk of stroke in patients at high risk for cardiovascular disease (Treat Guidel Med Lett 2005; 3:15). A recent issue of The New England Journal of Medicine includes the results of a study sponsored by the manufacturer in which 80 mg of atorvastatin (Lipitor – Pfizer) or placebo was given to 4731 patients without coronary artery disease who had had a stroke or transient ischemic attack (TIA) within one to six months before study entry (The Stroke Prevention by Aggressive Reduction in Cholesterol Levels [SPARCL] Investigators. High-dose atorvastatin after stroke or transient ischemic attack. N Engl J Med 2006; 355:549). Patients were not required to have elevated cholesterol levels to enroll. The authors conclude that the study results support starting atorvastatin treatment soon after a stroke or TIA.

The primary study endpoint was a nonfatal or fatal stroke. During a median follow-up of 4.9 years, patients treated with atorvastatin had 265 strokes compared to 307 strokes with placebo. Patients treated with atorvastatin had 56 fewer ischemic strokes and 22 more hemorrhagic strokes. They also had 39 fewer coronary events. There were 216 deaths among patients treated with atorvastatin and 211 among those treated with placebo.

Whether patients with a recent ischemic stroke or TIA would be as well protected against a recurrence and against coronary events by a lower dose of atorvastatin or by another less potent statin remains to be determined. The risk of myopathy and rhabdomyolysis with statins is dose-related; atorvastatin is the second-most potent statin on the US market (rosuvastatin is the most potent), and 80 mg is its maximum dose. Statins have an antithrombotic effect, and an increase in hemorrhagic stroke in patients with cerebrovascular disease treated with statins has been reported previously (Heart Protection Collaborative Study, Lancet 2004; 363:757). It is doubtful whether patients with a recent hemorrhagic stroke should be treated with statins at all, let alone a maximum dose of atorvastatin.

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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) patients being treated with the drug; two were taking the drug in combination with interferon beta for MS, and one was taking it with azathioprine for Crohn’s disease. PML is an opportunistic infection of the brain, caused by reactivation of the JC virus in immunosuppressed patients, that often causes death or severe neurological disability. There is no treatment for PML.

The publication of the natalizumab clinical trials in MS provided information on the drug’s effect on the progression of disability, which was not available when it was first reviewed here. In one study, combination therapy with natalizumab and interferon beta-1a for 2 years led to an estimated cumulative probability of progression of 23%, compared to 29% with interferon beta-1a alone (RA Rudick et al. N Engl J Med 2006; 354:911). In the second study, the estimated cumulative probability of progression over 2 years was 17% with natalizumab alone and 29% with placebo (CH Polman et al. N Engl J Med 2006; 354:899).

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The FDA has approved over-the-counter (OTC) sales of Plan B (Duramed), an emergency contraceptive package that contains two 0.75-mg tablets of levonorgestrel, to women ≥18 years old. Younger women still require a prescription. In one trial, two levonorgestrel 0.75-mg tablets taken 12 hours apart, the first within 72 hours after unprotected intercourse, decreased the pregnancy rate to 1%, compared to an expected rate of 8% (Task Force on Postovulatory Methods of Fertility Regulation, Lancet 1998; 352:428). How high doses of a progestin taken after coitus prevent pregnancy is unclear; they may interfere with ovulation, fertilization or implantation.

Nausea and vomiting can occur. The drug will not terminate an established pregnancy. No fetal malformations have been reported after unsuccessful use.

Plan B will not be available OTC until the end of the year, according to the manufacturer, and the OTC price is not yet available. The retail price for the prescription product varies from about $25 to $40. In order to enforce the age restriction, the drug will be kept behind the pharmacist’s counter, and a valid photo ID will be required.

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