Pharmacy Focus

Genentech revises Rituxan prescribing information

Genentech revised prescribing information for Rituxan after a patient with rheumatoid arthritis developed progressive multifocal leukoencephalopathy (PML). The patient, who developed a JC virus infection with resultant PML, received Rituxan in a long-term safety extension clinical study.

Healthcare professionals treating patients with Rituxan should consider PML in any patient presenting with new onset neurologic manifestations. Additionally, prescribers should consider consultation with a neurologist, brain MRI and lumbar puncture as clinically indicated.

Read the entire 2008 MedWatch Safety Summary at:

FDA studying statin drugs and amyotrophic lateral sclerosis (ALS)

An FDA analysis provides new evidence that the use of statins does not increase incidence of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease often referred to as Lou Gehrig's Disease.

The analysis, undertaken after the agency received a higher than expected number of reports of ALS in patients on statins, is based on data from 41 long-term controlled clinical trials. The results showed no increased incidence of the disease in patients treated with a statin compared with a placebo.

The FDA is anticipating the completion of a case-control or epidemiological study of ALS and statin use. Results from this study should be available within six to nine months. The FDA is examining the feasibility of conducting additional epidemiologic studies to examine the incidence and clinical course of ALS in patients taking statins.

Based on available information, healthcare professionals should not change their prescribing practices for statins and patients should not change their use of the drugs.

Read the entire 2008 MedWatch Safety Summary at:

Manufacturers of TNF-blocker drugs must highlight risk of fungal infections

The FDA has announced that the manufacturers of Humira, Cimzia, Enbrel and Remicade must strengthen the existing warnings, in the Warnings and Precaution sections of the drugs' prescribing information and Medication Guides, on the risk of developing opportunistic fungal infections.

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FDA approves safety-labeling changes for linezolid

The FDA has approved safety labeling revisions to provide updated information regarding medication contraindicated in patients receiving linezolid therapy.

According to Medscape, the agency approved the revisions in June "for linezolid (Zyvox tablets, oral suspension, and injection; Pfizer Inc.) to advise of contraindications to its use with monoamine oxidase inhibitors, serotonergic drugs, and agents that may increase blood pressure." Because "linezolid is a reversible nonselective inhibitor of monoamine oxidase," it "has the potential to interact with serotonergic and adrenergic agents."

Therefore, "use of linezolid is ... contraindicated in patients taking any medicinal product that inhibits monoamine oxidases A or B (e.g., phenelzine and isocarboxazid), or within two weeks of taking any such medicinal product."

The FDA warned that "postmarketing cases of serotonin syndrome have been reported in patients who were coadministered linezolid with serotonergic agents," so "linezolid therapy should be avoided in patients who have carcinoid syndrome, and/or are taking serotonergic agents such as serotonin reuptake inhibitors, tricyclic antidepressants, serotonin 5-HT1 receptor agonists (triptans), meperidine and buspirone."

FDA investigating link between Vytorin and a potentially increased incidence cancer

FDA officials are investigating a report of a possible association between the use of Vytorin and a potentially increased incidence of cancer found by researchers conducting the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) trial.

Vytorin is a combination product of simvastatin and ezetimibe used to decrease the production of cholesterol by the liver and inhibit the absorption of cholesterol in the intestine to reduce LDL-cholesterol levels and the risk of cardiovascular events.

The SEAS clinical trial tested whether lowering LDL-cholesterol with Vytorin would reduce the risk of cardiovascular events in individuals with aortic stenosis. A lower overall cardiovascular risk was not found with Vytorin. However, there was an additional observation that a larger percentage of subjects treated with Vytorin were diagnosed with and died from all types of cancer combined when compared to placebo during the five-year study.

The FDA anticipates receiving a final SEAS study report in about three months and the agency's review and evaluation of the clinical trial data should take about six months. The agency will communicate its conclusions and recommendations at that time. Healthcare professionals and caregivers should continue to monitor patients taking Vytorin and report side effects from the use of this drug to the agency.

Read the complete MedWatch 2008 Safety Summary at: