Is there any known interaction between glucosamine/chondroitin and atorvastatin? I took both for years and experienced muscle pain and soreness much of the time despite normal enzyme levels. Recently, I stopped the glucosamine, and the problems have resolved completely. — GLEN R. CALDWELL, PA-C, Kerrville, Tex.

The statins are catabolized through cytochrome P450, namely the CP3A4 isoenzyme. Increases in creatine kinase activity are common in patients on statins and may result in myopathy. In combination with other drugs utilizing this system, the risk of severe consequence (i.e., rhabdomyolysis) increases. There is very little information available on the bioactivity of supplements. Perhaps glucosamine or chondroitin is to blame. — Claire Babcock O’Connell, MPA, PA-C (144-9)