CNS Pharma Flashcards
GABAa activation –> ——-
GABAb activation —> —–
GABAa activation leads to incr Cl- INFLUX
GABAb activation lead to incr K+ efflux
both —> more neg inside the cell meaning HYPERPOLarization meaning INHIBITORY
Baclofen
GABAb agonist used in spasticity
What is the difference btw mechanism of action of BZs and barbiturates?
- BZs potentiate GABA, incr FREQ of GABA opening, no GABA mimetic activity
- barbiturates prolong GABA activity, incr duration of Cl- channel opening, have GABA mimetic activity at high doses
Benzodiazepine mechanism of action
- potentiates GABA
- increases FREQ of GABA opening
- NO GABA mimetic activity
Barbiturates mechanism of action
- prolong GABA activity
- increase duration of Cl- channel opening
- GABA mimetic at high dose
BZ1 mediates
sedation
BZ2 mediates
antianxiety and impairment of cognitive fxn
drugs that end in -azolam or azepam
are benzodiazepines
drugs that end in -barbital or -pental
are barbiturates
benzodiazepines end in the suffix
-azolam, -azepam
barbiturates end in the suffix
-barbital or -pental
long-acting BZs are good for
anxiety and panic disorder
short-acting BZs are good for
sleep disorder
ultra-short acting BZs are good for
pre-op sedation and anesthesia
midazolam
- type of drug?
- use?
- unique features?
ULTRA-SHORT t1/2 BZ metabolized to active compound by liver
therefore used for pre-op sedation and anesthesia
*IV
lorazepam
- type of drug?
- use?
- unique features?
BZ w/ long t1/2 and predictable kinetics therefore can use for status epilepticus
- also used for anxiety and pre-op sedation
diazepam
- type of drug?
- use?
- unique features?
- BZ w/ long t1/2 and liver metabolized to active compounds which makes its kinetics less predictable
- used for anxiety, pre-op sedation, muscle relax, WITHDRAWAL states (to alcohol)
- IV
Phenobarbital
- type of drug?
- use?
barbiturate used for seizures
b/c it’s long-acting
thiopental
barbiturate used for induction of anesthesia
b/c ultra-short acting
some important things about barbiturates
- general INDUCERS of cytochrome P450 (incr # P450 –> incr Vmax)
- contraindicated in porphyrias
- induce metabolism of most lipid-soluble drugs (OCPs, carbamazepine, phenytoin, warfarin, etc)
GABAa drugs are additive with other CNS depressants
- example of other CNS depressant include . . .
- consequence of adding . . .
- CNS depressants include anesthetics, antihistamines, opiates, beta-blockers
- combo can –> life-threatening respiratory distress
Buspirone
- no effect on GABA
- 5-HT1A partial agonist (meaning by self, behaves as agonist; in presence of agonist, behaves as a blocker)
- used for generalized anxiety disorder
- non-sedative
- 1-2wks to see effects
Non-BZs used in sleep disorders
think ZZZ=sleep Zolpidem, Zaleplon, EsZopiclone - BZ1 receptor agonist - less effect on cognitive fxn (b/c not BZ2) - less tolerance & abuse liability
BZ withdrawal signs
- rebound insomnia
- anxiety
- seizures when used as antieplipetic or in HIGH dose
Barbs and EtOH
- anxiety
- agitation
- life-threatening seizures (delirium tremens with EtOH)
Flumazenil
used to reverse BZ overdose (can’t for barbs & alcohol)
