Free drug levels monitoring as a detector of false metabolic refractory epilepsy.
Unbound and total plasma levels of carbamazepine (CBZ) and phenobarbital (PB) were evaluated in a group of 12 refractory patients out of 397 subjects, with normal values of total drug concentration and unbound levels below the expected ones. We established a minimal acceptable 'subtherapeutic' free drug level, i.e. less than 9.62 micrograms/ml for PB and 1.36 micrograms/ml for CBZ. PB and CBZ dosages were increased during a 3-month period. We observed a normalization of free levels, unaccompanied by a significant decrease in seizure frequency. Free drug level monitoring may prove to be an unchallenged detector of false metabolic refractory epilepsy.
Gianelli
M
M
Neurological Clinic, University of Turin, Italy.
Gentile
S
S
Verzè
L
L
Dimanico
U
U
Baruchello
M
M
Monaco
F
F
Mutani
R
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000927:Anticonvulsants / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002220:Carbamazepine / Q000493:pharmacokinetics* / Q000627:therapeutic use; D004827:Epilepsy / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010634:Phenobarbital / Q000493:pharmacokinetics* / Q000627:therapeutic use
D000927:Anticonvulsants; D002220:Carbamazepine; D010634:Phenobarbital