Anticonvulsants Flashcards
(33 cards)
How does binding GABA receptors elicit an inhibitory response?
hyperpolarizes the neuron by causing Cl influx
What are two GENERAL mechanisms of seizure generation?
1) altered membrane function
2) altered neurotransmitters
T/F: One misfiring neuron is enough to cause a seizure
False (must recruit surrounding neurons and propagate the signal)
To reach the CNS anticonvulsants must be ______ ______
lipid soluble
If dosing interval is greater than half life, what is the best way to address therapeutic failure
shorten the dosing interval
When does a drug accumulate
When dosing interval is shorter than the half-life
with a drug that accumulates, what is the best way to address therapeutic failure
increase the dose
With which relation of dosing interval to half-life is a missed dose likely to be less important?
When dosing interval is less than half-life
What should you not use when collecting samples to measure anticonvulsant concentrations?
Serum separator tube (can bind drug and artificially lower concentration)
The loading dose for a drug that accumulates is based on what
the drug’s half-life (longer half-life=larger loading dose)
Phenobarbital MOA
binds GABA receptors and inhibits glutamate and Ca influx
For which drug does the oral dose=IV dose
Phenobarbital
Important interaction of phenobarbital at the liver?
POTENT enzyme inducer (rapidly increases clearance of other drugs that go through hepatic metabolism…including itself)
Diazepam MOA
GABA agonist
which drug is first choice for status epilepticus and why?
Diazepam; rapidly penetrates the CNS
When giving phenobarb, seeing an increase in serum alk phos means what
induction (NOT disease)
What is phenobarb’s schedule?
Class IV
Why can’t diazepam be used long-term?
development of tolerance
The use of diazepam is contraindicated in which spp.?
Cats
Name 2 reasons KBr is a good choice for add-on therpay
1) it doesn’t share a mechanism of action
2) renally excreted (no hepatic concerns
Unique interaction of KBr?
competes with Cl…will be more readily excreted with high Cl (NaCl) diets
And indication for use of KBr as the sole anticonvulsant?
P with liver disease
Which drug is associated with GI upset?
KBr
Zonisamide MOA
decreases positive ion influx (targets Na and T Ca channels)
