Neuropharmacology Flashcards
(15 cards)
What is the mechanism of phenytoin and use?
It inactivates sodium channels with zero order kinetics. It prevents sustained high frequency repetitive neuronal firing. It binds inactive sodium channels and is use-dependent. It is used for all types of seizures except absence seizures. It is also used for status epilepticus along with BDZs.
What are the side effects of phenytoin?
Neuro: nystagmus, diplopia, ataxia, sedation, periph neuropathy
Tissue induction: Gingival hyperplasia, hirsutism, Steven Johnson syndrome, megaloblastic anemia, osteopenia
Teratogen: fetal hydantoin syndrome with broad nasum, cleft palate and small head
Liver/DDIs: CYP450 INDUCER
What drugs are used to treat absence seizures?
Etyhosuximide and valproic acid. Lamotrigine
What is unique about Ethosuximide compared to other epilepsy drugs?
Unlike other drugs which either inactivate Na channels or increase GABA, ethosuximide blocks T-type Ca channels in the thalamus.
What are the side effects of ethosuximide?
EFGHIJ: ethosux causes fatigue, GI distress, Head ache, itching, steve-Johnson.
What is unique about phenobarbital for treatment of epilepsy?
It is first-line in neonates for non-absence seizures.
Which epilepsy medications have GABA-mediated effects?
Levitiracetam, Topiramate, Valproic acid, Vigabatrin, Tiagabine, Gabapentin. They are NOT used for tonic-clonic seizures.
Which epilepsy drugs work by inactivating sodium channels?
Phenytoin, Carbamazepine, Valproate, Topiramate, Lamotrigine
Name the barbituates and their mechanism of action.
Phenobarbital, pentobarbital, thiopental, secobarbital.
They facilitate GABA-A action by increasing DURATION of Cl- channel opening and thus decrease neuronal firing.
what are the uses of barbituates?
They are used for sedation: anxiety, seizures, insomnia, induction of anesthesia(thiopental).
What are the toxicities of barbituates?
Respiratory and cardiac depression, CNS depression, dependence, CYP INDUCERS. OD Tx is supportive.
List the Benzodiazepines and their mechanism.
They facilitate GABA-A action by increasing FREQUENCY of Cl- channel opening. Most have long half-lives and long-acting. Short acting are ATOM: alprazolam, triazolam, oxazepam, midazelom. Long-acting are Diazepm, lorazepam, temazepam, chlordiazepoxide.
What are the uses of BDZs?
Anxiety, spasticity, status epilepticus, alcohol detox, night terrors (reduce REM sleep), sleep walking, general anesthesia(amnesia and muscle relax), insomnia.
What are the toxicities of BDZs?
dependence, additive CNS depression with ethanol, BUT less risk of respiratory depression. OD tx with flumazenil (competitive antagonist of BDZ receptor).
What are the ZZZ drugs?
Zolpidem, Zaleplon, eszopiclone are non-BDZ hypnotics. They act via the BZ1 subtype of the GABA receptor. Also reversed by flumazenil. They have a short duration via rapid liver metabolism and have decreased dependence. adverse is ataxia, HA and confusion.
