BetaBlockers Flashcards
Where are B adrenergic receptors present in body?
The heart has B1 (primary) and B2.
The JG-A cells of kidney have B1 receptors to release renin
Skeletal muscles have B2 receptors
Which B receptor are metoprolol, acebutolol, alprenolol, atenolol, betaxolol, celiprolol, esmolol, and nebivolol specific for?
B1
Which B receptor are propranolol, carteolol, penbutolol, pindolol, and timolol specific for?
They are nonspecific and have equal activity against B1 and B2
Which receptor B receptor is butoxamine specific for?
B2, but it is not a clinical agent. Experimental only
Which B receptor is propanolol specific for?
non specific.
Which B receptor is nebivolol specific for?
B1 specific. This is an exception to the N-Z rule.
What is esmolol? What is unique about it? What receptors is it specific for?
Esmolol is a B1 selective blocker (Second gen). Must be given by IV. Has and extremely short half-life, making it a favorite because it allows good control.
What B blockers are considered membrane stabilizing? What does membrane stabilizing mean?
propanolol, acebutolol, carvedilol all block fast Na channels and decrease slope of phase 0 depolarization, decreasing action potential and slowing down heart rate
What is intrinsic sympathomimetic activity?
What are some examples of drugs that do this?
drugs that normally block B receptors can also have a slight agonist effect on them, stimulating sympathetic action. Useful for treating excessive bradycardia.
pindolol and acebutolol are most notable examples.
A hypertensive patient has very low renin levels. Which drug would be a better choice: propranolol or pindolol?
Propranolol is most effective in patients with elevated renin levels, whereas pindolol is effective regardless of renin levels and has little effect on renin levels. Pindolol is the better choice
When are B blockers counter indicated with respect to the respiratory system?
in patients with asthma if possible because B blockers can cause bronchial constriction and unproductive cough.
When are B blockers counter indicated with respect to the brain?
B blockers that are lipid soluble can pass the blood brain barrier, and may cause CNS disorders, vivid dreams, or mental disorders. Switch to a more hydrophilic drug
When are B blockers counter indicated with respect to diabetics?
B-1 blockers can mask tachycardia common as a warning sign in hypoglycemia.
B2 blockers can inhibit hepatic glycogenolysis and pancreatic glucagon release, causing hypoglycemia.
What effect can B blockers have on the blood lipid profile?
B blockers increase TGs and decrease HDLs, especially those drugs that are beta nonspecific and hydrophilic
What are some of the most important toxicities of B blockers?
bradychardia, hypotension, arrhythimas, hypoglycemia or seizures.
