Anxiolytics Flashcards
Which benzodiazepine is used primarily for preoperative sedation?
midazolam [short-acting]
Which benzodiazepines are used as anxiolytics?
- alprazolam [intermediate]
- lorazepam [intermediate]
- diazepam [long-acting]
What is the main feature that distinguishes benzodiazepines from each other?
What is the margin of safety?
When are they lethal?
Do they cause dependence? addiction?
Benzos are indistinguishable except for their metabolic half-life.
The margin of safety is 100-fold so it is nearly impossible to commit suicide with them EXCEPT if they are mixed with another CNS depressant or alcohol.
They cause physical dependence WITHOUT addiction
What is the order of effects when taking an anxiolytic/sedative/hypnotic?
- anxiolytic
- sedation
- hyponotic
- anesthesia
- coma
What is the MOA of benzodiazepines?
They bind to a different site on the GABA-A receptor as GABA and act as a positive allosteric regulator.
GABA binds at a/b interface and benzo binds at a/g interface. In the presence of GABA, benzodiazepines increased Cl- flux through the channel by increasing FREQUENCY of channel opening
What 3 drugs/substances have binding sites of GABA-A receptor and exert anxiolytic/sedative effects?
- benzodiazepines [have a ceiling]
- barbituates [no ceiling]
- alcohol [no ceiling]
How are benzodiazepines metabolized?
Which is metabolized into long-lasting active metabolites?
Which are metabolized to shorter duration active metabolites?
Which is metabolized by glucuronidation and bypasses P450 [making it safer for the elderly]?
In the liver
Long-acting = diazepam
Intermediate = alprazolam
Short-acting = midazolam
Bypass P450 = lorazepam
You want to select a benzodiazepine for preoperative sedation. What do you select?
midazolam - anterograde amnesia
What benzodiazepine is prescribed for:
- anxiety
- agorophobia
- panic disorder
- hyponosis
alprazolam
Which benzodiazepine is prescribed for:
- anxiety
- seizures [esp. epilepticus]
lorazepam
Which benzodiazepine is prescribed for:
- anxiety
- muscle spasm
- seizure disorders
- alcohol detox
diazepam
When do benzodiazepines pose the greatest risk for adverse effects?
What delivery method of benzos has the narrowest safety margin?
When they are taken with other depressants [most often alcohol]
IV has a narrower safety margin
What is the typical response when benzodiazepines are withdrawn after long-term use? Why?
How do you avoid these symptoms?
Benzodiazepines cause physical dependence so the body functions normally in the presence of the drug. When it is withdrawn it causes:
- rebound insomnia
- excitement
- anxiety
- seizures [sometimes]
These symptoms can be avoided with a drug taper rather than abrupt stop of administration
Which benzodiazepines are most difficult to withdraw from?
Why?
Intermediate acting like lorazepam and alprazolam are notoriously difficult because they act long enough for the body to get dependence, but are short-acting enough that they don’t “self-taper” like the long-acting diazepam
What special consideration is given when dosing the elderly with benzodiazepines?
Lower dose, less frequently because they have reduced P450 in the liver so the drug can’t be detoxed as easily.
Also, the elderly already have lower levels of alertness, attention and memory
What are the 6 main therapeutic uses of benzodiazepines?
- anxiety
- insomnia
- epilepsy
- muscle relaxation
- anesthetic
- alcohol detox
Many of the specific anxiety disorders like OCD, panic disorders, PTSD, and social phobias are treated with _________________. More generalized and less specific anxiety is treated with ________________.
Specific = antidepressants generalized = benzodiazepines
Tolerance to the __________effects of benzodiazepines is not developed.
anxiolytic
What part of the brain and what receptors do benzodiazepines work on the decrease anxiety?
They work on GABA receptors in the amygdala