Antihypertensives Part II Flashcards
What is the mechanism of clonidine?
A2 agonist
*A2 receptor is a negative feedback mechanism for NE concentrations in the synapse. Clonidine works centrally, acting on the sympathetic inhibitory neuron(s) in the CNS
Is clonidine a 1st line tx for HTN?
No
*It is more commonly used for withdrawal with alcohol & benzos to prevent surg of NE is synapse (d/t upregulation) caused from withdrawal
What is mechanism of action for alpha-methyl-dopa?
Inhibits synthesis of NE
*think about how NE needs dopa, derived from tyrosine, to be made, so from the name of this drug its easy to remember that it interferes with dopa, therefore interfering with the synthesis of NE
Is alpha-methyl-dopa centrally acting?
Yes
What pt population are Beta blockers contraindicated in?
-Decompensated HF
-Asthma
-Watch out for masking of hypoglycemia in DM pts
*if you have poor contractility as it is, then you give a BB, then ur gonna throw them in cardiogenic shock, so don’t do that, thanks
BB can mask s/s of ____________
hypoglycemia
Tamsulosin is what kind of drug?
A1 blocker
What drug is used in pregnacy induced HTN?
*aka PIH
Methyldopa
With _________, a centrally acting anti-HTN agent, you can get rebound HTN if you hold it periop
Clonidine
Do you give clonidine DOS?
Yessssssssss
*will get rebound HTN due to upregulation because clonidine is an A2 agonist which acts as negative feedback to NE in synapse
How exactly do A2 receptors limit NE release into the synapse when the A2 receptors are bound by an agonist?
The A2 receptors inhibit adenylyl cyclase which decreases Ca++ influx into the presyaptic neuron which prevents the vescicle containing NE from releasing NE into the synapse
Dexmedetomidine is a ______ A2 agonist unlike clonidine which is a ______ A2 agonist
-Full
-partial
Reserpine depletes NE, dopamine and serotonin
Just a fact bro, ur welcome
Labetolol and carvedilol block what receptors?
*in a general sense
Beta and alpha
Phentolamine and phenoxybenzamine block what receptors?
A1 & A2
What drugs for pheochromocytoma?
-phenoxybenzamine
OR
-phentolamine
What drug name ending is for A1 blockers?
“zosin”
ex. Prazosin, Doxazosin, etc.
What 2 diseases are the “zosins” aka A1 blockers used for?
-BPH (most common)
-HTN
A1 blockers have _________ reflex tachycardia than nonselective alpha blockers
less
Prazosin is 50% _____ potent than Doxazosin
more
When blocking for pheochromocytoma, block ___ receptors before ____ receptors
A before B
*alpha before beta
Which alpha blockers have more extreme reflex tachycardia?
Non-selective
*because they block A2 receptors as well, which would act as ur negative feedback, but now you blocked them so ur HR is unopposed
Alpha blockers shouldn’t be used in ______ ______ or angina
Heart failure
What are the cardioselective BBs?
*meaning they are more selective to B1 receptors
*FYI according to nagelhout, there is no such thing as true cardioselective BBs because at the doses we are giving patients, the B1 selectivity is gone and they effect both B1 & B2. These drugs are only cardioselective at very small doses, smaller than what we give patients. This is scewed info from marketing these so called “cardioselective” drugs
-metoprolol
-esmolol
-atenolol
What are the mixed BBs?
*meaning they block alpha and beta receptors
-labetalol
-carvedilol
What is the most common non-selective BB?
-Propranolol
Do BB decreases activation of RAAS?
Yep
*remember B1 receptor activation in the JGA causes renin release
Don’t give any BBs to ______ patients
Asthma pts
Don’t stop BB after long term use why?
Can have withdrawal symptoms (tachycardia, angina, HTN, nervousness) d/t upregulated Beta receptors
If you start a BB DOS with a pt, they are at increased risk of ________. If you don’t give BB DOS and they are taking it long term then they will have an increased risk of ________
-stroke
-CV event (MI)
Don’t give a BB in pts with greater than a ___ degree heart block or complete heart block
1st degree HB
BBs can increase effects of __________ and _________
*anesthesia drug classes
-sedatives
-NDNMBs
BBs may cause significant _______ during NMB reversal
Bradycardia
Whats the short acting BB for HR that we will use in OR?
Esmolol
What is the short acting BB for BP that we can use in OR?
Labetalol
