Paralytic ileus combined with acute renal insufficiency induced by clozapine

A 64-year-old male patient received clozapine 125 mg twice daily for 6 years because of paranoid schizophrenia. The dose of clozapine was increased to 250 mg twice daily by doctor due to his symptoms occurred repeatedly. About one month after increase of drug dosage, the patient developed abdominal pain, distention, nausea, vomiting, and oliguria. Then the drug was stopped by the patient. Two days after the drug withdrawal, the patient visited emergency department in our hospital. Physical examination showed that the patient had abdominal swelling, abdomen tenderness, hypoactive bowel sounds. Laboratory tests showed serum creatinine (Scr) 106 μmol/L, blood urea nitrogen (BUN) 11.2 mmol/L. Abdominal X-ray showed dilatation of the small intestine with multiple ladder-like fluid level. Paralytic ileus was considered. Fasting, fluid supplement, anti-inflammatory, and gastrointestinal decompression were given. The next day, the renal function deteriorated, Scr and BUN levels were 606 μmol/L and 27.2 mmol/L, respectively; and his clozapine plasma concentration was 630 μg/L. Then it was considered that paralytic ileus combined with acute renal insufficiency was induced by clozapine. The patient was admitted to hospital and symptomatic treatments were given continuously. On day 3 after admission, the patient′s urine volume increased markedly. On day 5 after admission, abdominal pain and distention disappeared and day 8, his renal function returned to normal. Key words: Clozapine; Intestinal pseudo-obstruction; Acute kidney injury