复方磺胺甲噁唑致肾移植患者高钾血症

Hyperkalemia due to compound sulfamethoxazole in a patient after kidney transplantation

1例56岁女性患者行异体肾移植术后服用他克莫司(3mg、2次/d)、吗替麦考酚酯(500mg、2次/d)、泼尼松(20mg、1次/d)三联免疫抑制药物。术后1个月为预防感染口服复方磺胺甲噁唑0.48g、1次/d。用药前他克莫司血药浓度(CTac)6.56μg/L,血肌酐(Scr)142μmol/L,血钾4.3mmol/L;服用复方磺胺甲噁唑1周后CTac升至12.13μg/L,Scr147μmol/L,血钾7.1mmol/L;2周后CTac16.72μg/L,Scr176μmol/L,血钾8.3mmol/L,伴倦怠、双脚无力。停用复方磺胺甲噁唑,给予降钾治疗,并将他克莫司剂量降至2mg、2次/d,吗替麦考酚酯与泼尼松剂量同前。停用复方磺胺甲噁唑第3天,实验室检查示Scr175μmol/L,血钾4.7mmol/L;第8天CTac7.13μg/L,Scr150μmol/L,血钾4.8mmol/L。再次遵医嘱服用复方磺胺甲噁唑0.48g、2次/d,2周后血钾复升至6.2mmol/L。将复方磺胺甲噁唑逐步减量至0.48g、1次/d,0.48g、1次/隔日,8周后完全停用。停药后2周,血钾降至4.6mmol/L。此后复查未再发现高钾血症。

A 56-year-old female patient received triple-drug immunosuppressive therapy after allogenic renal transplantation, including tacrolimus 3 mg twice daily, mycophenolate mofetil 500 mg twice daily, and prednisone 20 mg once daily. The patient received compound sulfamethoxazole 0.48 g once daily for prevention of infection a month after operation. The laboratory tests showed that the levels of tacrolimus blood concentration (CTac), serum creatinine (Scr), and blood potassium were 6.56 μg/L, 142 μmol/L, and 4.3 mmol/L, respectively before medication, 12.13 μg/L, 147 μmol/L, and 7.1 mmol/L after 1 week of compound sulfamethoxazole treatment, and 16.72 μg/L, 176 μmol/L, and 8.3 mmol/L after 2 weeks, accompanied by lassitude and weakness of the feet. Compound sulfamethoxazole was stopped, potassium-lowering therapy was given, the dose of tacrolimus was reduced to 2 mg twice daily, and mycophenolate mofetil and prednisone were given at the same doses as before. Laboratory tests showed Scr 175 μmol/L and blood potassium 4.7 mmol/L on day 3 of compound sulfamethoxazole withdrawal and CTac 7.13 μg/L, Scr 150 μmol/L, and blood potassium 4.8 mmol/L on day 8. The patient took compound sulfamethoxazole 0.48 g twice daily again according to the doctor′s advice, and 2 weeks later, her blood potassium increased to 6.2 mmol/L. The dose of compound sulfamethoxazole was gradually reduced firstly to 0.48 g once daily, then to 0.48 g every other day, and was completely stopped 8 weeks later. Two weeks after drug withdrawal, her blood potassium decreased to 4.6 mmol/L. Hyperkalemia did not recur.