Alpha-2 Adrenergic Agents Flashcards
What is the effect of alpha 2 on pancreatic beta cells?
Inhibition of insulin secretion
What is the effect of alpha 2 on platelets?
Aggregation
What is the effect of alpha 2 on nerve endings?
Inhibition of NE synthesis
What is the effect of alpha 2 on fat cells?
Inhibition of lipolysis
What is the effect of alpha 2 on signaling intermediates and effectors?
Decreased cAMP
Which drugs are alpha 2 agonists?
Xylazine, detomidine, medetomidine, romifidine
Which drugs are alpha 2 antagonists?
Yohimbine, atipamezole, tolazoline
Which is the most selective: Xylazine or Medetomidine?
Medetomidine
In which ways can the alpha-2 agonists be administered?
IM & IV
For which species is Xylazine licensed?
Dogs, cats, & horses
True or False: Xylazine is a controlled substance.
FALSE: Xylazine is NOT a controlled substance.
What was the first alpha-2 adrenergic agonist approved for use in veterinary medicine?
Xylazine
What are the 3 therapeutic uses of alpha-2 agonists?
- Sedation
- Muscle relaxant
- Analgesia
What are the 3 therapeutic uses of Xylazine?
- Sedation and restraint: for radiographs, bandage changes, minor laceration repairs, wound care
- Visceral analgesia in horses
- Pre-anesthetic: in combination with an opioid
What 2 types of animals should NOT be given Xylazine?
- Older animals
2. Patients with cardiac conditions
For which patients should Xyaline be reserved?
Healthy patients
What are the GI effects associated with Xyalzine?
- Decreased GI motility
2. Emesis if not with held from food (90% of cats/10% of dogs)
What are the renal effects associated with Xylazine?
Increased urine output
How does Xylazine cause an increase in urine output?
Via suppression of anti-diuretic hormone release centrally
What are the uterine effects associated with Xylazine?
Increased contraction, leading to premature delivery in pregnant animals (oxytocin-like)
What are the respiratory effects associated with Xylazine?
- Minor hypoxemia in cattle and sheep
- Bronchoconstriction
- Pulmonary edema
- Increased airway resistance
True or False: Xylazine causes an increase in insulin release from the pancreas.
FALSE: Xylazine decreases plasma insulin levels
What are 2 sequelae to the decreased plasma insulin levels?
- Hyperglycemia
2. Glycosuria
Xylazine has synergistic actions with what other class of drugs?
Phenothiazines
What are 3 precautions to consider when using Xylazine?
- Not recommended for use in pregnant animals
- Monitor cardiopulmonary depression
- Must be avoided with cardiovascular, liver, and kidney diseases
Which of the following is most susceptible to Xylazine toxicity: horse, ruminant, cat, or dog?
Ruminant
What is the most potent alpha-2 agonist?
Medetomidine
Medetomidine is ____ times more selective than Xylazine.
10X
Which of the following can cause profound ataxia in horses at high doses: Xylazine or Medetomidine?
Medetomidine
What are the 3 alpha-2 antagonist?
- Yohimbine
- Atipamexole
- Tolazoline
What is the primary use for Yohimbine?
Reverse the sedative effects of Xylazine following short surgical procedures.
There are 6 adverse effects associated with the use of Yohimbine. Name 4.
- Tachycardia
- Salivation
- Muscle tremors
- CNS excitement
- Increased respiratory rate (dogs & cats)
- Removal of alpha-2 agonist analgesia