Anxolytic Agents Flashcards
At low doses these drugs have what type of effect? What are they used to treat?
anxiolytic; decrease anxiety, used to treat anxiety and apprehension
At moderate doses these drugs have what type of effect? What are they used to treat?
sedative; decrease activity and moderates excitement
At high doses these drugs have what type of effect? What are they used to treat?
hyypnotic; produces drowsiness and facilitates onset and maintenance of sleep
When are these drugs used for muscle relaxation?
only if associated with anxiety/CNS (does not work at the neuromuscular junction
What are the two types of CNS Depressants?
a. continuous CNS depressants
b. other type (“type b”)
How do Continuous CNS depressants work?
they continue to work more and more powerfully at higher doses. They have a well defined therapeutic index.
What are examples of continuous CNS depressants?
Barbituates, alcohol, chloral hydrate, GHB, and general anesthetics
BAGAC
How do “Type B” drugs work?
plateau and are more useful for sleep aids and axniety
What are some examples of “Type B” drugs?
Benzodiazepines (they are especially useful anxiolytics
Fun fact about diazepam:
aka valum; has alot better therapeutic index than older benzodiazepines. Phenobartbital has a therapeutic index of 2.0. Aka no thank you, come again
Mechanism for benzodiazepine:
Increase the affinity/activity of GABAa receptors for GABA, BUT ALONE DO NOT OPEN THE CHANNEL. This means it is not an agonist.
What are GABAa receptors?
They are ligand gated channels=fast inhibitory responses ( they are the primary inhibitory NT in the brain). They permit CL- ions to flow through the membrane, keeping cells potential negative, which makes action potentials less likely.
Mechanism for barbituates?
Increase the amount of opening by GABA AND at a high concentration can open in the ABSENCE of GABA. Increases the efficacy and affinity
Which are safer?
Benzodiazepines because tey do not increase the efficacy. The have the ability to produce a desired or intended result.
Classifications of Anxiolytics:
Barbituates vs. Benzodiazepines
Types of Benzodiazepines:
MALT-D: Midazolam (IV only), Alprazolam, Lorazepam, Triazolam, Diazepam
Types of Barbituates:
Phenobarbital, Thiopental, Pentobarbital
Where are most benzodiazepines metabolized?
Liver
What two of these are special and why are they special?
Lorazepam and oxazepam, they are fast acting and are rapidly metabolized. THEY HAVE NO METABOLITES
What is another special case?
Triazolam: it has active metabolites but bot triazolam and its metabolite have short half lives.
Which of the benzodiazepines are long acting?
Diazepam
Therapeutic affects of benzodiazepines:
Anti-anxiety- you dont want short acting
Sedation ( at low level, constant stimulation), Tolerance develops though
Hypnosis- fast acting work best
Anti-convulsants- diazepam for status epilepticus and alcohol withdrawls
Benzodiazepines and hypnosis:
Latency of onset is reduced, REM duration is decreased
. Tolerance develops
Side effects!!
Respiration- depression at the meduallary center; not as toxic as barbituates.
Euphoria- makes fast acting drugs more likely to be abused
Parodoxical excitement- release of punishment supression behavior
Anterograde amnesia- in ability to remember events occurring wile on drug
Interactions with other drugs
- Additive or even synergistic CNS depression
- Functional cross tolerance with ehtanol
- Oral contraception reduces diazepam elimination
- Asymmetric cross tolerance with Barbituates (metabolized by the same enzymes)
Benzodiazepine antagonist:
Flumazenil- short half life, IV only
Mechanism for Flumazenil
Binds to same spot as BZD on GABA
Thiopental
intravenous anesthetic, ULTRA SHORT ACTING
Pentobarbital
Sedatives, highly abused hypnotic
Phenobarbital
used in epilepsy
Other drugs used to treat anxiety (non sedatives)
Buspirone- very slow acting, used for chronic treatment. Not good for alcoholics
Beta-adrenergic blocker(propanolol)- short term treatment; decrease symp. tone
Alpha-2-agonist (Clonidine)- decrease symp tone, can cause sedation
Tricyclic anti. dep- for panic attacks
Zolipidem
other sedative hypnotic, act at BZD binding site. Sedative effects over anoxiolytic effects. Can decrease REM
Chloral hydrate
sedative hypnotic in institutions or pediatric clinics. CAN HAVE HEPATIC TOXICITY and decrease REM
Antihistamines (hydroxyine, diphenhydramine)
OTC sedatives/hypnotics; may synergize with morphine for analgesia. Have anticholinergic se: dry mouth
CONTRAINDICATED FOR PREGNANT WOMEN
These drugs are not analgetic
They do not treat pain
