Dialyzability of the antiepileptic drug zonisamide in patients undergoing hemodialysis.
OBJECTIVE
The influence of hemodialysis on plasma zonisamide (ZNS) concentration has not been clarified. In this study, the dialyzability of ZNS during hemodialysis was investigated in four ZNS-treated women with systemic lupus erythematosus complicated by seizures.


METHODS
The total and unbound plasma concentrations of ZNS were measured before and after hemodialysis. The concentration of ZNS in the spent dialysate also was determined.


RESULTS
The reduction in plasma ZNS concentration after a 4.5-h hemodialysis was 52.0 +/- 7.6%, and the dialyzer (BLF-16GW) clearance of ZNS was 55.1 +/- 7.0 ml/min. Dosage was gradually increased up to 200 to 500 mg/day, and the seizures were controlled satisfactorily.


CONCLUSIONS
The plasma concentration of ZNS was reduced by approximately 50% during one session of dialysis. For patients undergoing daytime hemodialysis sessions every 2 or 3 days, the usual dosage of ZNS (4-8 mg/kg/day) may be prescribed once a day in the evening. If seizures occur after hemodialysis, a supplemental daily dose may be prescribed in the morning.
Department of Pharmacy, Osaka Medical College Hospital, Osaka, Japan.
Yoshio
Y
Ijiri
Toru
T
Inoue
Fumio
F
Fukuda
Kaoru
K
Suzuki
Toyohide
T
Kobayashi
Nobuhisa
N
Shibahara
Hiroshi
H
Takenaka
Kazuhiko
K
Tanaka
D000328:Adult; D000927:Anticonvulsants / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D001002:Anuria / Q000097:blood / Q000453:epidemiology / Q000628:therapy; D015897:Comorbidity; D004334:Drug Administration Schedule; D005260:Female; D015312:Hemodialysis Solutions / Q000032:analysis; D006801:Humans; D007555:Isoxazoles / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000453:epidemiology / Q000628:therapy*; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000453:epidemiology; D008875:Middle Aged; D011485:Protein Binding; D006435:Renal Dialysis; D012640:Seizures / Q000097:blood* / Q000188:drug therapy* / Q000453:epidemiology; D000078305:Zonisamide
D000927:Anticonvulsants; D015312:Hemodialysis Solutions; D007555:Isoxazoles; D000078305:Zonisamide