anticonvulsants

Question 1

phenobarbital (epiphen)

Answer 1

type: barbiturate, anticonvulsant
effects: anti-epileptic effect when used at a subanesthetic dose
mechanism: decreases Ach, glu, norepi, increases GABA? not known
adverse effect: sedation/lethargy, PUPD, ataxia, polyphagia, hepatotoxicity, CYP enzyme induction
adverse effects in cats also include blood clotting disorders and allergic reactions, non-linear kinetics =minor change in dose can result in large fluctuations in blood levels

Question 2

potassium bromide (KBr)

Answer 2

type: anticonvulsant
extremely long half-life 
renal elimination, no hepatic metabolism
food interactions: Cl- and salt 
- avoid salty treats and low salt cardiac diets

Question 3

adverse effects if KBr

Answer 3

sedation, v+, D+, increased hunger and thirst, pelvic limb weakness or stiffness, pancreatitis, skin reactions, occasional behavioural changes
not recommended for cats - coughing and bronchial asthma

Question 4

diazepam (valium)

Answer 4

used to treat status epilepticus in cats and dogs
if given IV it crosses BBB quickly
rectal bioavailability is 50%
hepatic metabolism

Question 5

diazepam adverse effects

Answer 5

lethargy, sedation, ataxia, hyperactivity?, increased appetite, seizures may occur after abrupt discontinuation of chronic diazepam
reports of fulminant hepatic necrosis in cats

Question 6

levetiracetam (Keppra)

Answer 6

efficacy in dogs
usually used in combo with phenobarbital and/or KBr
high oral availability 
short half-life 
renal excretion

Question 7

Gabapentin

Answer 7

block Ca2+ channels?
not used much in vet med for seizures
adverse effects: uncommon, very mild sedation, ataxia (transient)

Question 8

pregabalin

Answer 8

used in combo with PB and KBr

vets like gabapentin more since it’s been around longer

Question 9

imepitoin

Answer 9

not as good as phenobarbitol but safer