Therapeutic serum drug concentrations in epileptic dogs treated with potassium bromide alone or in combination with other anticonvulsants: 122 cases (1992-1996).
OBJECTIVE
To determine therapeutic serum drug concentrations in epileptic dogs treated with potassium bromide.


METHODS
Retrospective study.


METHODS
122 dogs with major motor epilepsy.


METHODS
Medical histories were collected for epileptic dogs treated with potassium bromide with or without phenobarbital sodium or primidone, from which serum was submitted for bromide analysis from May 1992 to May 1996 to the Therapeutic Drug Monitoring Program at Cornell University's College of Veterinary Medicine. A therapeutic response (improved seizure control) was defined as a > or = 50% reduction in seizure frequency following initiation of bromide treatment. Serum bromide and phenobarbital concentrations and therapeutic outcome were determined for all dogs.


RESULTS
72% of epileptic dogs had a > or = 50% reduction in seizure frequency following initiation of treatment with potassium bromide. Discontinuation of barbiturate treatment was possible in 19% of those dogs originally treated with phenobarbital or primidone. Of those dogs continued on bromide and phenobarbital, 45% maintained seizure control with serum phenobarbital concentrations < 20 micrograms/ml. Significantly higher serum bromide concentrations were required when dogs were initially or eventually treated with bromide alone (mean bromide concentration, 1,906 micrograms/ml) compared with dogs treated with potassium bromide along with a barbiturate (mean bromide concentration, 1,621 micrograms/ml).


CONCLUSIONS
When dogs are treated with bromide and phenobarbital, a reasonable therapeutic range for serum bromide concentrations is 810 to 2,400 micrograms/ml, and for bromide treatment alone, the range is 880 to 3,000 micrograms/ml. When phenobarbital is used in combination with bromide, a reasonable therapeutic range for serum phenobarbital concentrations is 9 to 36 micrograms/ml, although in some dogs treated with bromide, phenobarbital can eventually be discontinued.
Trepanier
L A
LA
Department of Pharmacology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Van Schoick
A
A
Schwark
W S
WS
Carrillo
J
J
D000818:Animals; D000927:Anticonvulsants / Q000097:blood / Q000627:therapeutic use*; D001965:Bromides / Q000097:blood / Q000627:therapeutic use*; D004283:Dog Diseases / Q000097:blood / Q000188:drug therapy*; D004285:Dogs; D004359:Drug Therapy, Combination; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy / Q000662:veterinary*; D005500:Follow-Up Studies; D010634:Phenobarbital / Q000097:blood / Q000627:therapeutic use*; D017680:Potassium Compounds / Q000097:blood / Q000627:therapeutic use*; D011324:Primidone / Q000627:therapeutic use; D012189:Retrospective Studies; D016896:Treatment Outcome
D000927:Anticonvulsants; D001965:Bromides; D017680:Potassium Compounds; D011324:Primidone; C039004:potassium bromide; D010634:Phenobarbital