Lithium poisoning: pharmacokinetics and clearance during different therapeutic measures

The clinical features and pharmacokinetics of 22 lithium overdoses are described. Effectiveness of different treatment regimens regarding elimination of lithium is discussed. Origin of overdose was due to deliberate poisoning or precipitated by concomitant diseases, coadministration of drugs, or combination of both. Treatment included supportive care, diuretics (15/22), hemodialysis (HD; 9/22), and mechanical ventilation (3/22). Severity of lithium intoxication was classified in 50% as I degrees, in 41% as II degrees, and in 9% as III degrees according to Hansen and Amdisen. Renal impairment on admission was diagnosed in 82% of the patients. Half-life of lithium in serum was 3.5 +/- 0.8 hours during the first HD, and 29 +/- 14 and 29 +/- 6 hours during therapy with diuretics or supportive treatment, respectively. Lithium clearance during HD was 160 +/- 15 mL/min, and renal clearance during HD or treatment with diuretics was approximately 20 and 15 +/- 9 mL/min, respectively. Renal lithium clearance was not influenced by HD therapy. There was no difference regarding half-life and clearance between the group that had an unspecific treatment or the group treated with diuretics. Hemodialysis is the therapy of choice for emergent extracorporeal lithium elimination. Renal impairment and interaction with other drugs were the main reasons for intoxication; thus, more cautious prescription or more frequent supervision of this patient group is warranted. It seems that treatment with diuretics does not have a beneficial effect in the overdose setting.