Clozapine-induced interstitial nephritis - a rare but important complication: a case report

INTRODUCTION: Given the limited range of effective drug treatments for patients with schizophrenia, increasing numbers of patients, often termed 'treatment-resistant' are prescribed clozapine. While the induction of neutropenia or agranulocytosis by clozapine is well appreciated, other rare potentially fatal adverse reactions may also occur including acute interstitial nephritis as reported in this case. CASE PRESENTATION: A 57-year-old Caucasian woman with treatment-resistant chronic schizophrenia developed acute renal failure following initiation of treatment with clozapine. The adverse reaction occurred after only four doses of the drug had been administered (titrated from 12.5 to 25 mg per day). After clozapine had been withdrawn, the patient's renal function returned to normal with no other changes to medication. The patient had been exposed to clozapine about 4 years previously when she had developed a similar reaction. CONCLUSION: Renal reactions to clozapine are extremely rare but, if not recognized promptly, may prove fatal. Psychiatrists need to be aware of this possible complication when clozapine is initiated.