Phenothiazines and benzodiazepines Flashcards
What does a tranquilizer do?
Induces a state of behavioral change wherein anxiety is relieved and the patient is relaxed, although aware of their surroundings.
What does a sedative do?
induces a state characterized by CNS depression and drowsiness, decreased awareness of surroundings.
What is antinociception?
The diminished ability to feel pain
What makes up the BBB?
tight capillary endothelial junctions, glial cells which further seal it, and active transport mechanisms (like P-glycoprotein) to remove organic acids or bases.
What are the excitatory NTs?
glutamate and acetylcholine
What are the inhibitory NTs?
GABA and glycine
Which class of tranquilizers are the only ones to have analgesic effects?
alpha-2 agonists.
What is the most common phenothiazine?
acepromazine
What is the mechanism of action of phenothiazines?
they competitively antagonise excitatory dopamine receptors in the CNS, inhibit vomiting, increase prolactin release, and cause muscle relaxation.
T/F: phenothiazines can variably block histamine, alpha-1 and acetylcholine receptors.
True.
Do phenothiazines cross the BBB?
yes
What are the effects of phenothiazenes on the CNS?
sedation, decreased spontaneous motor activity, hypothermia and hyperprolactinemia, and anti-emetic.
What are the effects of phenothiazenes on the cardiovascular system?
they block alpha-1 receptors, cause hypotension via vasodilation.
What breed of dogs are more sensitive to the cardiovascular effects of phenothiazines? What gene mutation causes this?
boxers (MDR1 mutants). Large breed dogs and sighthounds can also be more sensitive.
When should you not use acepromazine?
anytime that vasodilation is contraindicated.
T/F: acepromazine can cause dogs to be easily startled, increased aggression, and CNS stimulation.
True.
Is there a reversal agent for acepromazine?
No. You must wait 2-4 hours for the clinical effects to wear off
Which benzos have flumazenil as a reversal agent?
diazepam and midazolam
What is the MOA of benzos?
they bind and activate benzodiazepine binding site on GABA receptor to cause hyperpolarization of neurons.
Can benzodiazepines cross the BBB?
yes.
Which benzodiazepine is given IV most commonly?
diazepam
Which benzo can you give IM?
midazolam.
Why is diazepam contraindicated in cats?
because it can cause hepatic necrosis.
When is is flumanezil useful?
in the case of benzodiazepine toxicity.
Why would you want to be cautious when using a benzo in an aggressive dog?
can cause disinhibition.
