A consumer advocacy group is asking government regulators to recall a drug they approved last year for a little-understood pain ailment, saying the pill can lead to dangerously high blood pressure.

A letter Wednesday from Public Citizen calls on the Food and Drug Administration to pull Savella off the market, almost exactly a year after it was cleared to treat fibromyalgia.

The drug is co-marketed by Forest Laboratories Inc. and Cypress Bioscience Inc.

Fibromyalgia is characterized by a wide range of pain-related symptoms, including muscle soreness, headache, fatigue and depression. Last summer European regulators rejected the drug due to lack of effectiveness data and side effects. Public Citizen argues the FDA should have reached the same conclusion.

"FDA should never have approved Savella for fibromyalgia, and should now immediately undo its error by removing it from the market," states the petition from Dr. Sidney Wolfe, director of Public Citizen's Health Research Group.

Company studies of the drug showed 20 percent of patients taking Savella had hypertension, or high blood pressure, compared with 7 percent of those taking a dummy pill. Savella, known generically as milnacipran, is part of an antidepressant class of drugs that have been associated with increased blood pressure.

Public Citizen also points out that the original study of Savella failed to meet the companies' own study goals for effectiveness. Company scientists reanalyzed the study, with a larger population and a shorter time span and recorded relatively meager benefit: 9 percent of patients on Savella significantly reduced their pain, compared with 7 percent of those taking placebo.

Public Citizen cites complaints from FDA's own statistical reviewer, who wrote: "there is no evidence ... that milnacipran is associated with improvements in pain or improvements in function at three months of therapy."

Since the FDA approved Savella last January, doctors have written more than 250,000 prescriptions for the drug, according to data from IMS Health.

A Forest Laboratories spokesman handling Savella did not immediately return calls for comment Wednesday morning.

FDA has cleared two other treatments for fibromyalgia: Eli Lilly's antidepressant Cymbalta and Pfizer's anti-seizure treatment Lyrica. Both drugs were cleared based on their ability to decrease fibromyalgia pain, though it's not clear how.

The cause of fibromyalgia is not known, though some researchers point to abnormalities in how patients with the disorder process pain nerve signals.

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