Lecture 1: Sedative Hypnotics and Anti-Anxiety Drugs Flashcards
How do Sedative-Hypnotics and Anxiolytics generally work?
a. What does this cause?
They Bind to a MODULATORY SITE on the GABAa Receptor Complex.
a. Intensifies or Prolongs the Actions of GABA
GABAa Receptor Complex
- When GABA binds to the GABAa Receptor complex, what channels open up?
a. What does this do?
- Cl- channels
a. Hyperpolarizes the membrane, DEPRESSING Synaptic Transmission.
Sedative Hypnotics act as what?
As DEPRESSANTS of the CNS
Barbituates
- How do they work?
a. What does this do?
b. What is another way they could work INDEPENDENT of GABA?
- Bind to GABAa Receptor
a. Increases DURATION of GABA action
b. They could Increase Cl- Influx, causing INHIBITION w/o GABA
Barbituates
- Marked CNS Depressant: What 2 things can they produce?
- Margin of Safety level?
a. What are 2 major problems?
b. What do they DECREASE at HIGH Doses?
- Hypnosis and Surgical Anesthesia
- Low
a. Toxicity and Overdose
b. Respiratory Drive
Barbituates
- Are they abusive?
a. Why?
b. Type of Scheduled drug?
- Yes
a. Cause EUPHORIA
b. 2 or 3
Barbituates
- Effects of CNS depressants are what?
a. what does this mean?
b. This is especially true when combined with what?
- Super-Additive
a. Depression caused by 2 drugs together is more than what we would predict w/a similar dose of one.
b. ALCOHOL
Barbituates: Pharmacokinetics
- Best way to get them into the body?
a. How about getting into the CNS? - What determines duration and rate of Onset?
- Metabolized by what?
a. What do they induce?
- Oral
a. They simply enter the CNS quickly and Easily - Degree of LIPID SOLUBILITY
- Liver
a. Hepatic Enzymes w/Chronic Use…has a SIGNIFICANT ALTERATION on the METABOLISM of OTHER DRUGS, esp. Alcohol, hormones, and other barbituates.
Barbituates: Uses
- Phenobarbital
a. Length of duration?
b. Use? - Thiopental
a. Length of Duration?
b. Use?
- a. Long-acting
b. Anticonvulsants - a. Short
b. Induction of ANESTHESIA
Barbituates: Side Effects
- CNS Depression: Name the 4?
- What can it do to sleep?
- What other side effect is important to note?
- Distortion of Mood, Drowsiness, Impaired Judgement, Impaired Motor Skills
- Decrease REM Sleep
- Paradoxical Excitement
Barbituates: Side Effects (2)
- They’re especially dangerous when combined with what?
- Severe Overdose is marked by what 3 things?
- Best Tx for Overdose is Supportive Therapy; However, what can actually INCREASE the Mortality Rate?
- How are they cleared from the system?
- Alcohol
- Coma, Decreased BP, and Respiratory Depression
- Stimulants
- Diuresis and Alkalinization of the urine.
Barbituates: Contraindications
- Barbituates Enhance the Synthesis of what?
a. So what are they CONTRAINDICATED in? - What other thing are they Contraindicated in?
- Withdrawal can be LIFE THREATENING
a. What are the symptoms (6)
b. Severity of Withdrawal depends on what?
- of Porphyrin
a. in any form of Porphyria (Abnormal heme Synthesis) - In the Presence of Pulmonary Insufficiency (can cause major Respiratory Depression)
- a. Anxiety, Hyperactive reflexes, Orthostatic Hypotension, Restlessness, Seizures, and Weakness
b. Increases w/Dose and the Amt of time it’s been used.
Benzodiazepenes: General
- Most commonly used group of what?
- Produce CNS Depression with what 2 things accompanied?
- At Higher doses, what can occur?
- What drug can cause MUSCLE RELAXATION?
- What 3 Drugs have ANTICONVULSANT Effects?
- Anxiolytics and Sedative-Hypnotics
- Decrease in Anxiety that’s usually accompanied by Drowsiness
- Hypnosis
- Diazepam
- Clonazepam, Lorazepam, and Diazepam
Benzodiazepenes: Mechanism of Action
- What do they bind to?
- What do they do to the Actions of GABA?
a. When do they work? - As concentration of the Drug INCREASES, what happens to GABA?
a. What does cause?
b. Which means what for these drugs?
- a SPECIFIC RECEPTOR Associated w/the GABAa Receptor Complex
- they INTENSIFY the actions of GABA by Enhancing its Binding to the GABAa Receptor
a. ONLY when GABA is Present - It’s Release is INHIBITED
a. a CEILING EFFECT, thus respiratory Depression is less likely than w/barbituates
b. They’re RELATIVELY SAFE!
Benzodiazepenes: Pharmacokinetics
- Best way to administer?
a. Other way and reason to do so?
b. Rapid uptake into what first?
- Oral
a. IV for Emergencies and Pre-Anesthesia
b. Brain, then redistribution to other tissues, like Fat…thus, Duration of Action may not always reflect BLOOD LEVELS or Metabolism