ALPHA 2 Flashcards
What was clonidine first developed as?
A nasal decongestant
Clonidine was developed in the 1970s and later recognized for its sympatholytic properties.
What are the three subtypes of alpha2 adrenergic receptors?
- Alpha2a
- Alpha2b
- Alpha2c
What clinical effect is linked to the inactivation of the locus ceruleus?
Sedation
What hemodynamic effects are primarily seen with alpha2 adrenergic agonists?
- Hypotension
- Bradycardia
What chemical categories do alpha2 adrenergic agonists belong to?
- Phenylethylates (methyldopa, quanabenz)
- Imidazolines (clonidine, dexmedetomidine)
- Oxaloazepines
How much more potent is clonidine at alpha2 receptors compared to alpha1?
200x more potent
What is the elimination half-life of clonidine?
12-24 hours
How does the alpha2 activity of dexmedetomidine compare to clonidine?
8x greater alpha2 activity
What is the distribution half-life of dexmedetomidine?
6 minutes
What are some clinical effects of alpha2 adrenergic agonists?
- Analgesia
- Sedation
- Hypotension
- Anti-shivering properties
- Mild ventilatory depression
What is one use of alpha2 adrenergic agonists in preoperative settings?
Sedation/anxiolysis/amnesia
What percentage decrease in anesthetics can clonidine produce?
20-40%
True or False: Dexmedetomidine can be used post-extubation without causing respiratory depression.
True
What is the recommended dose of clonidine for labor analgesia?
30-150 mcg epidural
What should the dose of alpha2 adrenergic agonists be limited to during labor analgesia to prevent fetal heart rate depression?
1 mcg/kg
What is a common use of alpha2 adrenergic agonists for chronic pain management?
Combination epidural lidocaine/clonidine
What effect does peripheral stimulation of alpha2b receptors have after a rapid IV bolus?
Transient hypertension
Fill in the blank: The elimination half-life of dexmedetomidine is _______.
2 hours
What type of pain management can alpha2 adrenergic agonists provide for cancer pain?
Epidural continuous infusion
What is the effect of alpha2 adrenergic agonists on sympathetic response during intubation?
Blunts sympathetic response
What is the effect of alpha2 adrenergic agonists on local anesthetic blocks?
- Increased quality and duration of block
- May cause hypotension
What are the effects of alpha2 adrenergic agonists in special populations like drug addicts?
Increased sympathetic tone
