Anticonvulsants Flashcards
Diazepam: trade name, drug family, controlled?
Valium
Benzodiazepine
Is controled
Diazepam: use, administration route(s)
Most common drug to stop active seizures
IV (slowly, best route), per rectum, intranasal
Diazepam: cautions (2)
Do not give rapidly IV: causes cardiac arrhythmias
Do not give IM: poorly absorbed due to propylene glycol solvent
Diazepam: why it’s not used for chronic siezures (dogs and cats)
Dogs: has a short half life, dogs quickly develop a tolerance
Cats: repeated dosing can cause acute liver failure
Midazolam: trade name, drug family, controlled?
Versed
Benzodiazepine
Is controlled
Midazolam: use, administration route(s)
Stop active seizures
IV (preferred), IM
Levetiracetam: trade name, use, route(s) of administration, controlled?
Keppra
IV: stop active seizures
PO: adjunct medication to manage chronic seizure disorders
Not controlled
Phenobarbital: drug family, use, controlled?
Barbiturate
PO: most common primary anticonvulsant for idiopathic epilepsy
Injectable: stop an active seizure, or provide an initial loading dose
Is controlled
Phenobarbital: long T1/2
A loading dose may be given to reach a therapeutic blood level faster
Can give one large dose, or multiple regular doses more frequently
It takes several days to reach a new steady state after starting or changing doses
Phenobarbital: CYP enzymes
Is metabolized by CYP enzymes in the liver
Induces CYP enzymes production, causes the liver to metabolize it faster over time
Dose may have to increase over time to maintain therapeutic levels
Phenobarbital: potential side effects (4)
Initial sedation, should wear off over time
PU/PD
Polyphagia (and resulting weight gain)
Serious liver damage
Phenobarbital: serum concentration monitoring
Purpose: to ensure the drug concentration is in the therapeutic range and not toxic or sub-thereputic
DVM usually requires repeat testing every 6-12 months
Don’t use a serum separator (tiger/gold top) tube, drug binds to the separator gel and will give a falsely decreased value
Phenobarbital: serum drug concentration monitoring timing
Peak value: 4-6 hours post AM dose
Through value: Just before PM dose
Wait ~14 days after starting/dose change to test due to long T1/2
Phenobarbital: additional testing
Hepatic enzyme levels: mild increases are benign in most cases, but abnormal patterns/spikes can indicate hepatic damage
Bile acids test: assess liver function
Potassium Bromide: use, pharmacokinetics, controlled?
Primary or adjunct anticonvulsant in dogs
Not metabolized by the liver
T1/2 = 24 days! Steady state takes 4 months, but allows for SID dosing
Using a loading dose can cause excessive sedation
Not controlled
