ABSTRACT
OBJECTIVES: Favipiravir is an antiviral that is being evaluated for the treatment of COVID-19. Use of favipiravir is associated with elevation of serum uric acid levels. Risk factors for the occurrence of hyperuricemia are unclear. METHODS: Specimens from COVID-19 patients who received 10 days of favipiravir in a previous clinical trial (jRCTs041190120) were used. Serum favipiravir concentrations were measured by LC-MS. Factors associated with the development of hyperuricemia were investigated using logistic regression analysis. Optimal cut-off values for the baseline serum uric acid levels and steady-state serum favipiravir concentrations in predicting the occurrence of hyperuricemia were determined by ROC curve analysis. RESULTS: Among the 66 COVID-19 patients who were treated with favipiravir for 10 days, the steady-state serum favipiravir concentrations were significantly correlated with serum uric acid levels. High baseline serum uric acid levels and steady-state serum favipiravir concentrations during therapy were factors associated with the development of hyperuricemia. The cutoff baseline serum uric acid level and steady-state serum favipiravir concentration during favipiravir administration determined to predict hyperuricemia were 3.7 mg/dL and 46.14 µg/mL, respectively. CONCLUSIONS: Patients with high baseline serum uric acid levels or who achieved high steady-state serum favipiravir concentrations during therapy were susceptible to hyperuricemia.