Seizure Medications Flashcards
Phenobarbital
barbiturate that is GABA ergic activity prolongs chloride activity at the GABA a receptor
also thought to inhibit glutamine receptors and voltage gated calcium channels
Gold standard in cats
Caution in hepatic disease
S/E: takes 15-20 minutes to reach therapeutic levels in the CNS when given IV, takes weeks to reach therapeutic levels when given orally, sedation/hypotension/hypoventilation when loading, sedation during the first month, elevated liver values and potential lowering of values over time - check levels 2-3 wks after dose change (steady state reached in 5 half-lives) and every 6 to 12 months, myelosuppression, skin disease, PU/PD, ataxia, weight gain and increased appetite
therapeutic levels believed to be 20-40mcg/mL with increased risk of hepatotoxicity when > 40, superficial necrolytic dermatitis, decreases blood levels of thyroid hormone
Levetericatem
Binds to the synaptic vesicle protein SV2A which results in decreased neurotransmitter release into the synapse
Works quickly, no to minimal side effects - sedation
safe in cats!
100% oral bioavailabilty
can do an IV loading dose of 60mg/kg
Zonisamide
sulfonamide drug with multiple MOAs via inhibition of:
- voltage gated sodium channels
- T-type calcium channels
- modulates dopaminergic activity
- carbonic anhydrase activity
and enhances GABA activity in the CNS
appears safe in cats
levels are around 10-40mcg/mL
half life in dogs is 17 hours so it is given twice daily - measure levels at least 4 days after
half life in cats is 32 hours so it is given once daily
co-administration with phenobarbital decreases the half life as well as levels but unclear how to change the dose
newer and minimal side effects: ataxia, sedation, and GI upset. Potential for KCS and idiosyncratic hepatotoxicity like all sulfonamide drugs
KBr
halide anti-convulsant that causes hyper-polarization of the neuron via movement of bromid ions intracellularly through chloride channels. The bromide itself is not metabolized and is excreted by the kidneys - caution in renal disease!!
also takes a while to reach therapeutic levels - half life is 25 days!!!
CANNOT USE IN CATS due to risk of fatal pneumonitis
effects chloride results on blood gas analyzers
can load it orally over 5 days or even give it rectally, although the latter can cause GI upset
bromide levels in blood are 0.8-2.4-3mg/mL
S/E in dogs: PU/PD, PP, sedation and ataxia, vomiting, pancreatitis
Ideally would not administer chloride containing fluids to patients in the hospital but if bromism, or toxicity occurs (Which is manifested as neuro signs, paresis, etc.) then give 0.9% saline and
Benzodiazepines
GABA-ergic
diazepam causes more sedation
good in the emergency treatment but don’t last very long
midazolam can be given IN, IV, and IM, less sedating, good for CRI b/c water soluble
diazepam needs to be given IN, IV or rectally, has propylene glycol which can cause hepatotoxicity when given PO in cats and is lipophilic so should be given in central vein
clorazepate - orally
S/E: tolerance, short half-life
