Colchicine-Induced Acute Neuromyopathy in a Patient Using Concomitant Fluconazole: Case Report and Literature Review

A 54-year-old woman presented at the emergency department after experiencing lower limb weakness and bilateral ankle pain for 2 days. She had a history of type 2 diabetes mellitus, diabetes mellitus nephropathy with chronic kidney disease, and chronic gouty arthritis. She had received 0.6 mg colchicine orally once or twice daily for 8 months. Four days prior to her emergency department visit, she was discharged from our nephrology ward, where she had been admitted because of a urinary tract infection. During hospitalization, she was treated with intravenous cefazolin for 7 days. Because of persistent symptoms, we performed repeated urinalysis, which revealed the presence of yeast. She was diagnosed with fungal cystitis, and was administered a 7-day course of once-daily oral fluconazole (100 mg). On day 5 of the course, she was discharged and asked to continue taking oral colchicine (0.6 mg, twice daily), as well as fluconazole for the full 7-day course. Neurological examination revealed marked symmetrical weakness (Medical Research Council grade 4/5). Her sensation and coordination were intact. Initial laboratory investigation revealed hyperkalemia (6.2 mmol/L), and blood urea nitrogen, serum creatinine, and creatine kinase levels of 181, 11.16 mg/dL, and 803 U/L respectively. Her liver function tests showed elevated alanine aminotransferase levels (112 U/L). Electromyographic results were consistent with colchicine neuromyopathy. Ten days after treatment cessation, muscle enzyme levels normalized and weakness gradually disappeared. We used the Drug Interaction Probability Scale to evaluate our patient’s case. A score of 5 was calculated, indicating that the drug–drug interaction was the probable cause of neuromuscular toxicity.