QUININE SULFATE, VITAMIN E ARE CATEGORY III FOR NOCTURNAL LEG CRAMP
QUININE SULFATE, VITAMIN E ARE CATEGORY III FOR NOCTURNAL LEG CRAMP treatment, FDA concludes in the tentative final monograph (TFM) for drug products to treat or prevent such cramps. Published in the Nov. 8 Federal Register, the TFM concurs with the recommendations of the Internal Analgesic Panel's report on the classification of quinine sulfate. FDA said it agrees that "until controlled studies show that a quinine dose of not more than 325 mg daily is safe and useful for relief ]or prevention[ of nocturnal leg cramps, the drug should not be generally recognized as safe and effective for this use." Schering-Plough recently introduced an OTC muscle relaxant, Legatrin, which contains quinine sulfate. The company said it will submit new clinical data to FDA "shortly" in support of the efficacy of quinine sulfate. FDA stated that issues to be addressed in any clinical studies before quinine can be reclassified from Category III to Category I are: "(1) Is quinine effective in treating and/or preventing nocturnal leg muscle cramps in low daily doses (e.g., 200 to 325 mg) over short periods of time (e.g., 7 days or less)? (2) If short-term quinine treatment with low doses is not significantly effective in reducing recurrent episodes of nocturnal leg muscle cramps, must such medication be taken over extended periods of time to obtain relief? If yes, how long a period of time? (3) What are the adverse effects experienced by subjects exposed to effective doses of quinine over an effective course of therapy?" The agency also classified vitamin E, which was not reviewed by the Miscellaneous Internal Panel, as Category III. FDA said that none of the submitted papers "contained controlled studies to show the efficacy of vitamin E in the treatment of nocturnal leg cramps." In addition, the agency cited one paper which raises some questions about the safe dose of vitamin E. FDA classified all other OTC ingredients for nocturnal leg cramps in Category II. FDA also proposed a warning for products containing quinine which states: "Discontinue use if ringing in the ears, deafness, skin rash, or visual disturbances occur. Do not take if pregnant, sensitive to quinine, or under 12 years of age." The OTC Miscellaneous Internal Panel had noted that quinine's more serious side effects include induction of abortion and occasional cases of autoimmune thrombocytopenic purpura and hemolytic anemia. The panel also pointed out that nocturnal leg cramps occur in middle life and beyond and therefore quinine should not be used by children.
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