Lithium intoxication due to carbamazepine-induced renal failure

OBJECTIVE: To report the case of a patient with manic-depressive disorder w ho developed lithium intoxication following carbamazepine-induced acute ren al failure. CASE SUMMARY: A 33-year-old white man with bipolar manic-depressive disorde r was treated with lithium for the last 18 months. Three weeks prior to adm ission, carbamazepine 600 mg was added to the drug regimen due to a recurre nce of the psychiatric disorder. He was admitted with signs of lithium into xication. Acute renal failure due to carbamazepine-induced interstitial nep hritis was diagnosed. DISCUSSION: The combination of carbamazepine and lithium is known to cause neurotoxicity. We describe a different interaction in which the toxic lithi um concentrations were the result of carbamazepine-induced acute renal fail ure. CONCLUSIONS: When considering adding carbamazepine to lithium, careful foll ow-up of the patients is warranted to prevent this indirect drug interactio n.