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Pharmacy Focus

FDA requires boxed warning for metoclopramide

The Food and Drug Administration is requiring that manufacturers of metoclopramide, a drug used to treat gastrointestinal disorders, must add a boxed warning, the strongest warning the FDA requires, to drug labels about the risk of its long-term or high-dose use.

Chronic use of the drug has been linked to tardive dyskinesia, which may include involuntary and repetitive movements of the body, even after the drugs are no longer taken.

Drug manufacturers also must ensure patients are provided with a medication guide that discusses this risk.

The current labeling warns of the risk of tardive dyskinesia with chronic metoclopramide treatment. The development of this condition is directly related to the length of time a patient is taking the drug and the number of doses taken. Those at greatest risk include the elderly, especially older women, and people who have been on the drug for a long time.

Tardive dyskinesia is characterized by involuntary, repetitive movements of the extremities, or lip smacking, grimacing, tongue protrusion, rapid eye movements or blinking, puckering and pursing of the lips, or impaired movement of the fingers. These symptoms are rarely reversible and there is no known treatment. However, in some patients, symptoms may lessen or resolve after metoclopramide treatment is stopped.

Metoclopramide works by speeding up the movement of the stomach muscles, thus increasing the rate at which the stomach empties into the intestines. It is used as a short-term treatment of gastroesophageal reflux disease in patients who have not responded to other therapies, and to treat diabetic gastroparesis (slowed emptying of the stomach's contents into the intestines). It is recommended that treatment not exceed three months.

Metoclopramide is available in a variety of formulations including tablets, syrups and injections. Products with metoclopramide include Reglan Tablets, Reglan Oral Disintegrating Tablets, Metoclopramide Oral Solution and Reglan Injection.
Information: http://www.fda.gov/bbs/topics/NEWS/2009/NEW01963.html

FDA: Zonisamide shown to cause metabolic acidosis

The FDA is urging healthcare workers to measure serum bicarbonate before treating patients with zonisamide. The drug, which is indicated as an adjunctive therapy in treating partial seizures in epileptic adults, can cause metabolic acidosis in some patients as shown in updated clinical data, according to the FDA.

Patients with predisposing conditions or therapies may be at greater risk for developing the condition and the risk of zonisamide-induced metabolic acidosis appears to be more frequent and severe in younger patients.

The FDA recommends physicians measure serum bicarbonate both before and during treatment with zonisamide, even in the absence of symptoms.

Read the MedWatch 2009 safety summary, including a link to the "Information for Healthcare Professionals" sheet, at http://www.fda.gov/medwatch/safety/2009/safety09.htm#Zonisamide

FDA list summary of drug warnings, changes

The December 2008 posting on the FDA website includes a list of 50 drug products that have undergone safety labeling changes. To view the list and for information on specific changes, click on the following link: http://www.fda.gov/medwatch/safety/2008/dec08_quickview.htm