Q: 23 year old male is admitted to ICU after intentional overdose of carbamazepine. Serum concentrations of carbamazepine (select one)

A) may not peak for over 24 hours
B) may not peak for over 48 hours
C) may not peak for over 72 hours
D) may not peak for over 96 hours
E) Serum carbamazepine cannot be measured, and should be followed clinically.


Answer: D

Serum concentrations may not peak for over 96 hours. It is clinically important to closely follow levels every four to six hours. Though studies have shown correlation varies between concentrations of carbamazepine and clinical signs, but linear trend is expected.


References:

1. Graudins A, Peden G, Dowsett RP. Massive overdose with controlled-release carbamazepine resulting in delayed peak serum concentrations and life-threatening toxicity. Emerg Med (Fremantle) 2002; 14:89.

2. Tibballs J. Acute toxic reaction to carbamazepine: clinical effects and serum concentrations. J Pediatr 1992; 121:295. 

3. Brahmi N, Kouraichi N, Abderrazek H, et al. Clinical experience with carbamazepine overdose: relationship between serum concentration and neurological severity. J Clin Psychopharmacol 2008; 28:241.