Neurotoxicity and nephrotoxicity caused by combined use of lithium and risperidone: a case report and literature review

BACKGROUND: Combination lithium, a mood stabilizer, and risperidone, an atypical antipsychotic drug, is widely used for treatment of psychotic disorders. Rare reports concern severe adverse drug reaction in multiple organic systems with their combined use. We report two episodes of neurotoxicity and nephrotoxicity in a patient following the combined use of lithium and risperidone. CASE PRESENTATION: A 55-year-old male had a diagnosis of schizoaffective disorder at the age of 51. He was initially treated with a combination of lithium and olanzapine 5 to 15 mg/day for 2 years. He was admitted to psychiatric ward at the age of 53 due to manic episode with psychotic feature. Because of poor blood sugar control, we switched olanzapine 20 mg/day to risperidone 4.5 mg/day with combination of lithium 900mg/day. The patient presented neurotoxicity, neuroleptic-malignant-syndrome like symptoms, and nephrotoxicity, elevation of blood creatinine and decreased urine output few days later. These signs were fully recovered within 2 days after we discontinued all medications and gave normal saline hydration. Then we re-administered decreased dosage of lithium 600 mg/day and risperidone 3 mg/day, and the similar episode occurred again 3 days later. All drugs were discontinued again, then his delirium resolved and abnormal data returned to normal 1 day later. Finally, the patient was treated with risperidone 2 mg/day as monotherapy, and no episode of neurotoxicity and nephrotoxicity appeared in the following 2 years. CONCLUSIONS: The case exemplifies neurotoxicity and nephrotoxicity after combined use of lithium and risperidone. These adverse effects resolved soon after discontinuing these medications and adequate hydration. Clinicians should be cautious about neurological and renal adverse effects.