Multiple delayed peak lithium concentrations following acute intoxication with an extended-release product.
OBJECTIVE
To describe delayed peak lithium concentrations after an overdose of extended-release lithium tablets.


METHODS
A patient with borderline personality disorder and depression ingested extended-release lithium approximately 20.25 g along with other agents. At presentation, the lithium concentration was 1.4 mEq/L. Significant enteral intake was initiated 27 hours after presentation and the lithium concentration 5 hours later increased to 3.2 mEq/L. A second lithium peak concentration of 5.0 mEq/L was noted 40 hours after presentation. Two hemodialysis sessions lasting 4 hours each were performed along with administration of sodium polystyrene sulfonate in sorbitol 20% to enhance lithium elimination and decrease absorption. Eighty-eight hours after presentation, the lithium concentration had decreased to 1.5 mEq/L.


CONCLUSIONS
Delayed and secondary peak lithium concentrations have been reported following an overdose with an extended-release product. Extended-release lithium may form an aggregate in the gastrointestinal tract and/or have delayed absorption secondary to coingested drugs. Toxicity may result if the patient begins enteral intake of drugs, fluids, or nutrition.


CONCLUSIONS
Continued monitoring of lithium concentrations after an acute ingestion with an extended-release product are recommended until lithium concentrations are less than 1.5 mEq/L and there are no signs of toxicity, particularly once the patient begins significant enteral intake.
Dupuis
R E
RE
Division of Pharmacy Practice, University of North Carolina, Chapel Hill, USA.
Cooper
A A
AA
Rosamond
L J
LJ
Campbell-Bright
S
S
D000328:Adult; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000097:blood / Q000506:poisoning*; D003692:Delayed-Action Preparations; D006801:Humans; D008094:Lithium / Q000008:administration & dosage / Q000097:blood / Q000506:poisoning*; D008297:Male
D000928:Antidepressive Agents; D003692:Delayed-Action Preparations; D008094:Lithium