Antiepileptic Drugs

Front 1

What properties do we want in a drug to treat the medical emergency status epilepticus?

Back 1

Can be given I/V.

Rapid onset.

Min. Cardio and resp effects.

Front 2

What drugs can we use to treat status epilepticus?

Back 2

Diazepam/Midazolam

Phenobarbital.

Levetiracetam.

Propofol.

Demedetomidine.

Front 3

What is the drug of choice for treat status epilepticus?

Back 3

Benzodiazepine such as diazepam or midazolam.

Front 4

Mechanism of action of diazepam and midazolam?

Back 4

Binds to GABA-A receptors, potentiating the movement of Cl- ions into the cells.

Front 5

Pharmokinetics of diazepam?

Back 5

Highly lipid soluble.

Highly protein bound.

Low clearance which is decreased by cimetidine.

Half life is species dependant- cats 6x longer

Metabolized by oxidation then glucuronide conjugation.

Front 6

How can we give diazepam?

Back 6

Can give orally, I/V or per rectum.

Front 7

Side effects of diazepam?

Back 7

Hepatic necrosis in the cat which can be fatal.

Monitor hepatic parameters as a result.

Front 8

Pharmokinetics of midazolam?

Back 8

Water soluble and ionised at pH 3.5

Higher clearance

Hydroxlylation and glucuronide conjugation.

Highly bound to plasma protein.

Can administer I/V, I/M and intranasally.

Front 9

Ideal properties of a drug that can be used to manage epilepsy?

Back 9

Long duration of action.

Good oral absorption.

Can cross BBB.

Metabolic tolerance limitted.

Minimal sedation.

Consistant clinical response.

Absence of major side effects (hepatotoxicity).

Front 10

Drugs commonly used in the management of epilepsy?

Back 10

Imepitoin.

Phenobarbital.

Potassium bromide.

Levetiracetum.

Benzodiazepines.

Front 11

Which AEDs lead to enhanced GABA synaptic transmission?

Back 11

Barbituates.

Benzodiazepines.

Imepitoin.

Front 12

How does potassium bromide work as an AED?

Back 12

Enters ECF.

Crosses neuronal CL- channels more readily than CL-

GABA enhances the influx of bromide leading to hyperpolarization.

Front 13

Pharmokinetics of Phenobarbitol?

Back 13

Dogs mainly.

Potentiates synaptic inhibition through GABA receptor.

Oral absorption slow but good.

25% renal excretion unchanged and alkalinisition of urine enhances this.

Rest is oxidative hydroxylation and glucuronide conjugation.

Potent inducer of microsomal enzymes.

Front 14

Mechanism of action of imepitoin?

Back 14

Partial agonist with low affinity for the BDZ binding site of GABA receptor.

Targeted- only binds when GABA present.

Front 15

Pharmokinetics of imepitoin?

Back 15

Oral bioavailability decreased wit food.

Hepatic metabolism (oxidation)

Inactive metabolites (faecal excretion)

No induction of microsomal enzymes.

Half life 2 hours.

Steady state rapidly achieved.

Front 16

What drug is potassium bromide synergistic with and when would we use them together?

Back 16

Phenobarbital used for uncontrolled seizures.

Front 17

Pharmokinetics of potassium bromide?

Back 17

Kidney excretion.

Half life in dogs 1 month.

3-6 months for steady state.

High chloride diet increased elimination and decrease half life.

Front 18

Indications for using potassium bromide?

Back 18

Uncontrolled seizures with phenobarbitol.

Dogs with hepatotoxicity.

Pre-existing liver disease.

Side effects of phenobarb.

Front 19

Mechanism of action of levetiracetum?

Back 19

Inhibits neurotransmitter release.

Front 20

Side effects of AEDs ?

Back 20

Sedation.

Polphagia.

PUPD.

Ataxia.

Hepatotoxicity.

Front 21

Side effects off KBr in cats?

Back 21

Asthma like symptoms and gingival hyperplasia.

Front 22

How do we set up dosage schedules for AEDs?

Back 22

Based on incidence and severity of seizures.

Reduce gradually when stable after 6 months.

Front 23

How common is epilepsy in cats and what is it usually to do with?

Back 23

Not as common as in dogs.

Tends to be to do with a structural problem..