CNS Drugs 1 Flashcards
Triazolam
Benzodiazepine
Diazepam
Sedative-hypnotic, benzodiazepine
*PROTOTYPICAL
“valium” “mother’s little helper”
Lorazepam
Benzodiazepine, Sedative hypnotic/anxiolytic
Estazolam
Benzodiazepine, sedative-hypnotic/anxiolytic
Flumazenil
Benzodiazepine Antagonist
*Mainly used in combined EtOH/BZD OD.
MOA: direct acting competitive antagonist that binds to the BZD receptor site on GABAa receptors, prevents increase in GABA activity.
Pentobarbital
Barbituate
Phenobarbital
Barbituate
Benzodiazepines (BZDs)
Long acting (Anxiety disorders and waking frequently at night): Diazepam
Intermediate acting (Long-term sedation and cannot stay asleep): Estazolam, Lorazepam
Short acting (For difficulty falling asleep, assoc. with retrograde amnesia): Triazolam
MOA: Increases the affinity of GABA for the GABA-A receptor which increases the FREQUENCY at which the Cl- channel opens in response to GABA. Binds to benzodiazepine receptor site on GABAa between alpha and gamma-2 subunit– changes tertiary structure
Effects: Increases Cl- conductance which shunts depolarization = CNS depression. Since they are agonist at the site, but inhibit NT effect, they are INVERSE AGONISTS
“State-dependent action”: BZD action dependent on the status of GABA release. As the drug depresses CNS fxn, GABA release is reduced. Therefore BZDs have a ceiling effect, = little respiratory depression.
Toxicity: Very hard to kill a patient by OD = ceiling effect through CNS depression/GABA release reduction. IV use can have significant respiratory depression at very high doses. *Characteristic signs of CNS depression. Dirrahea, epigastric distress, bitter taste, nausea, vomitting, rare hallucination.
Withdrawal is mild, can have rebound insomnia, anxiety, increased reflexes, excessive motor activity, headache.
Can induce drug hang-over (reduced alertness, groggy feeling)
Benzodiazepine antagonist
Flumazenil
Barbituates
Pentobarbital (induces coma in status epilepticus)
Phenobarbital (Managing generalized seizures)
*Risk of respiratory depression HIGH
“drug automatism”: patient awakens, takes another pill, and this cycles until fatal consequences occur, originated with this drug class.
Commonly causes drug hangover.
MOA: binds to the Cl ionophore site independent of GABA binding site.
Increases time the gate is open in presence of GABA. *Opposite of BZDs, barbs can open Cl gate in ABSENCE of GABA (at high dose)
*no ceiling effect, dose-dependent increase in Cl conductance.
Toxicity: Easily produce coma/death, at high dose, can block Ca channels No ceiling effect. *potent CYP450 enzyme inducers, biotransformation increased = complication of therapy w/ other drugs
*Differential rates of tolerance, respiratory depression=antiepileptic efficacy in tolerance, «sedation tolerance
Other sedatives/hypnotics
Zolpidem (least likely to produce rebound insomnia with little muscle relaxant effects)
Meprobromate (older agent with greater potential for toxicity in OD)
Eszopiclone (For chronic use sedation with less tolerance)
Remelteon (Melatonin agonist with no adverse side effects seen with other drugs in same class. Not as good of a sedative)
MOA: all work on Cl channel.
Sedative/Anxiolytics
Buspirone (no dependence, no sedation, no anti-epileptic activity)
Propranolol
*All have anxiolytics, but are not anxioselective
Situational Anxiety drugs
Propranolol
Anti-spastic Drugs
Baclofen
Propranolol
Sedative-hypnotic and Antitremor drug
MOA: beta adrenergic non-specific antagonist
Anxiolytic may be due to increased activity of the locus ceruleus, blocking the action of NE reduces locus ceruleus activation of central nucleus of the amygdala
Use: preferred for situational anxiety– stage fright *can also use for essential tremor
Buspirone
Anxiolytic
Use: reduced anxiety with absence of sedation w/ few other actions
MOA: 5HT-1A partial agonist with small anti-dopaminergic component, reduces firing of raphe nucleus
Effects: do not have typical sedative-hypnotic effects, are without tolerance/cross-tolerance with BZDs
Toxicity: headache, dizziness, and nervousness
*not effective in management of panic attacks, where SSRIs are.
Baclofen
Anti-spastic drug
MOA: works on presynaptic terminals in spinal cord to ease spasticity. inhibits transmission of both monosynaptic and polysynaptic reflexes, possibly by hyperpolarization of primary afferent fiber terminals = antagonism of the release of excitatory NTs. *Hence, reduces the afferent reflexes that mediate spasticity. B/c of GABAb specificity, it produces less sedation than BZDs at doses that = anti-spasticity effects.
Toxicity: High doses can still be sedating, withdrawal can = hyper-spastic symptoms and seizure.
*For high doses that would = sedation, pumps are used intrathecally, allows for high levels of baclofen in spine w/o significant sedation
Eszopiclone
Other sedative/hypnotic “Lunesta”
BZD-like agent, “safe for chronic use”
Remelteon
Other sedative/hypnotic
New type of sedative, works at melatonin agonist at MT-1 receptor
Zeleplon
Other sedative/hypnotic “Sonata”
Short duration effect for those who have problems falling asleep, but not used for staying asleep.
*clears system rapidly, no drug hangover
Drugs for Parkinson’s
Carbidopa/Levadopa (indirect-acting DA agonists)
Indirect-acting DA Agonists
Benztropine Selegiline Rasagiline Tolcapone Entacapone Stalevo
Anti-muscarinic agents
Trihexyphenidyl
Benztropine
Direct-acting DA Agonists
Pramipexole
Ropinirole
Other drugs used
Clozapine
Huntington’s and Tourette’s Drugs
Haloperidol
Antitremor Drugs
Propranolol
Ethanol
Dystonia Drugs
Antimuscarinics
Benzodiazepines
BoTox
AD/HD Drugs
Methylphenidate
Adderall
Atomoxetine
Benztropine
Indirect-acting DA agonist/Antimuscarinic, Antipsychotic
DAT inhibitor and ACh antagonist
Use: other PD drug also Antipsychotic
Effects: Dual action- DA uptake inhibitor (DAT) and antimuscarinic mixes actions and enhances effect, both effectively overcome the deficiency of DA in the striatum at two locations in the pathway
Toxicity: produces unwanted side effects when used to treat PD, secondary to treatment with antipsychotic drugs anticholinergic properties produce sedation and other antimuscarinic effects including memory clouding/constipation
Selegiline
Indirect-acting DA agonist
converted to amphetamine and methamphetamine
MOA: MAO-B selective at normal doses, reuptake inhibitor. Contributes to effects by inducing DA release. Increases synaptic DA pool, and overall DA tone. *Normal DA release, extends duration
Toxicity: Can be a problem in working PD patients due to conversion to amphetamine (drug testing) Blocks MAO-A at high doses, but no tyramine effect.
Rasagiline
Indirect-acting DA agonist
MOA: MAO-B preferring with MAO-A blocking at normal doses, higher concentrations (pressor amine effect).
*Does not convert to amphetamine
Toxicity: MAO-A1 effect at high dose (NE neurons)
Tolcapone
Indirect-acting DA agonist
MOA: blocks COMT in peripheral and central CNS
Effect: increases bioavailability of levodopa to brain, and increases duration of levodopa action (reduced catabolism) *Crosses BBB
Toxicity: liver toxic!
Entacapone
Indirect-acting DA agonist
MOA: Block COMT in periphery only. *Does not cross BBB
Use: increases the bioavailability of Levodopa
Trihexyphenidyl
Antimuscarinic / Antipsychotic
Clean antimuscarinic, with typical anticholinergic side effects
MOA: very little inhibition of DAT, primarily antimuscarinic
Pramipexole
Direct-acting DA agonist
Use: used in early stage monotherapy, delays the requirement of levadopa.
MOA: Synthetic full intrinsic activity agonist (D2 and D3 agonist) with no D1 activity.
Effects: neuroprotective: may slow progression of PD. Similar efficacy to levadopa in early stage, but not as effective in late stage. Antidepressant action work against “amotivational” stage.
Toxicity: more hallucination, less dyskinesias. Associated with sleep attacks (all DA agonists), associated with OCDs (gambling, hypersexuality, risk taking
Ropinirole
Direct-acting DA agonist
effects: neuroprotective
Toxicity: more hallucinations, less dyskinesias
Clozapine
Other drug (PD) and 2nd generation Antipsychotic (atypical)
Use: drug of choice for hallucinations in PD patients, Antipsychotic
MOA: has little affinity for D-2 receptors in striatum, more potent D4 antagonists. Also potent antimuscarinic
Effects: produces agranulocytosis, peridoxical wet pillow due to high antimuscarinic activity,
Toxicity: Very low EPSE, no TDs, high sedation and orthostasis. High weight gain
Haloperidol
Use: HD and Tourette’s
High TI
Effects: decreases DA = treatment for movement disorder AND psychosis