Acute myopathy in a patient with concomitant use of pravastatin and colchicine

OBJECTIVE: To report a case of acute myopathy after concomitant use of colchicine and pravastatin. CASE SUMMARY: A 65-year-old woman was admitted to the hospital with an acute episode of gout, She had been taking pravastatin 20 mg once daily for 6 years. On admission, blood urea nitrogen and serum creatinine levels were 48 mg/dL and 1.3 mg/dL, respectively. Colchicine 1.5 mg/day was added to the treatment regimen, but 20 days after the initiation of colchicine therapy, symmetrical proximal muscle weakness developed in the woman's legs. Physical examination, laboratory findings, and electromyelogram findings suggested myopathy. The Naranjo probability scale indicated a probable relationship between myopathy and combined therapy. Seven days after discontinuation of colchicine and pravastatin, the patient's weakness improved and enzyme levels returned to normal. Colchicine was restarted at 1.0 mg/day 5 days later; no myopathy occurred. DISCUSSION: Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) and colchicine are known to cause myopathy. Most of the statins and colchicine are biotransformed in the liver primarily by the CYP3A4 system, which may increase the risk of myopathy when concurrent therapy is used. However, pravastatin is not primarily metabolized by cytochrome P450 isoenzymes. The cause of myopathy in our patient may be related to the interaction of colchicine and pravastatin via P-glycoprotein. In addition, the presence of mild renal dysfunction could have contributed to the development of myopathy. CONCLUSIONS: We suggest that clinicians be aware that neuromuscular toxicity can occur in patients with mild renal dysfunction with combined use of colchicine and pravastatin.