Lecture 27: Cardio Pharm Flashcards
What is ISA activity?
Intrinsic sympathomimetic activity
Blocks strong stimulation of beta receptors by endogenous EPI and NE but act as weak agonists at beta receptors
Useful for patients who need beta blocker but get adverse cardiac effects from too much beta receptor blockade
What are drugs with ISA activity?
Beta blockers:
Pindolol (nonselective)
Acebutolol (beta1 selective)
What are therapeutic uses for beta blockers?
Angina
HF
MI
Some cardiac arrhythmias
Explain angina pectoris
Chest pain triggered by O2 supply demand imbalance
What are determinants of MVO2 (oxygen demand)?
HR
IS
AL
How might some angina patients have low oxygen supply?
Some patients have low coronary blood flow from underlying coronary artery disease
What is the most likely explanation for efficacy of beta blockers in treatment of angina?
Beta blockers decrease HR
How do beta blockers decrease AL?
Decrease afterload by decreasing BP
How do beta blockers help with angina?
Dec. oxygen demand
Dec. HR, IS, BP (which dec. AL)
Inc. oxygen supply indirectly
Dec. HR = longer diastole (more filling time) = inc. CBF
How do beta blockers help with HF?
Dec. bad effects from sympathetic activation = dec. oxygen demand, dec. cardiac hypertrophy + remodeling
Antiarrhythmic effects
How do beta blockers help with cardiac arrhythmias?
Dec. conduction = inc. refractoriness in AV node
What are beta blocker AEs?
HF, sinus bradycardia, AV block
Inc. airways resistance in patients with asthma/COPD
DM + hypoglycemia episodes
Impaired peripheral circulation in patients with PVD (beta2 vasodilation blocked)
Only which beta blockers have established efficacy for HF?
Metoprolol
Carvedilol
Bisoprolol
What is phentolamine?
Nonselective alpha blocker
What are prazosin and tamsulosin?
Alpha1 blockers
What are therapeutics for alpha 1 blockers?
HPT (for strong)
Block vasoconstriction = dec. SVR = dec. BP
What are alpha1 blocker AEs?
Orthostatic hypotension
Less reflex tachycardia than nonselective alpha blocker
What is phenylephrine and midodrine?
Alpha1 selective agonists
What is clonidine and alpha-methyldopa?
Alpha2 selective agonists
What are therapeutic uses for alpha2 agonists?
HPT (not first line)
What is the MOA of alpha 2 agonists?
Act at alpha2 receptors in medulla oblongata to dec. sympathetic tone to CV system
Act at presynaptic alpha2 receptors to decrease NE release
What are alpha 2 agonists AEs?
Sedation
Xerostomia
What are DRIs and what do they act on?
Direct renin inhibitors
Act on renin
“Kirens”