Abstract:

Colchicine plays an important role in the treatment of gout and some other diseases. Besides gastrointestinal symptoms, myopathy has been reported as a rare side effect of colchicine in some patients. We report a case of myopathy in a patient with chronic kidney disease caused by high-dose colchicine, and then review literature on colchicine-induced myopathy, so as to provide some experience for the clinical diagnosis, treatment and medication safety. A 51-year-old male patient with 10 years of gout and 5 years of chronic kidney disease history and irregular treatment was admitted to the hospital with complaint of recurrent left wrist arthralgia and emerging lower extremities myalgia after intake of 40-50 mg colchicine in total within 20 days. Laboratory examinations showed significantly increased creatine kinase (CK) and then colchicine-induced myopathy was diagnosed preliminarily. After withdrawl of colchicine and implementation of hydration, alkalization and intramuscular injection of compound betamethasone, the symptoms of arthralgia and myalgia were relieved within 3 days and CK decreased to normal range gradually. According to literature reports, colchicine related myopathy was mostly characterized by proximal myasthenia and myalgia, accompanied by elevated CK level, which usually occurred days to weeks after initial administration of colchicine at the usual dosage in patients with renal impairment or a change in the underlying disease state in those receiving long-term therapy, and the features might remit within three to four weeks after the drug was discontinued. Electromyography of proximal muscles showed myopathy marked by abnormal spontaneous activity and muscle pathology waa marked by accumulation of lysosomes and autophagic vacuoles. Chronic kidney disease, liver cirrhosis, higher colchicine dose and concomitant cytochrome P450 3A4 (CYP3A4) inhibitors were associated with increased risk of myo-pathy. Based on the similar efficacy and lower adverse reaction rate compared with larger dosage, small dose of colchicine was recommended by many important current guidelines and recommendations in the treatment of gout. In consideration of potential risks, colchicine should be used with caution in patients with kidney or liver impairment, and in those taking CYP3A4 or P-glycoprotein inhibitors. For those patients, the drug dose should be adjusted and the latent adverse reactions should be monitored carefully.

Key words: Colchicine, Myopathy, Side effect