Flashcards in alpha and beta blockers Deck (14):
phenoxybenzamine: use, mechanism, side effects
irreversible alpha blocker. used preoperatively for a pheochromocytoma to prevent a hypertensive crisis. may cause orthostatic hypotension and reflex tachycardia.
phentolamine: use, mechanism, side effects
reversible alpha blocker that can be given to pts on MAO inhibitors who eat tyramine-containing foods
What drugs are used to treat urinary symptoms of BPH and hypertension?
alpha 1 selective blockers. all end in -osin. (prazosin, terazosin, doxazosin, tamsulosin).
What is one use of specific use of prazosin?
may be used for PTSD in addition to use for urinary symptoms of BPH and hypertension
Side effect of prazosin
first dose orthostatic hypotension, dizziness, headache. also seen with terazosin, doxazosin, etc.
mirtazapine mechanism and use
alpha-2 selective blocker. used to treat depression but may casue sedation, incr. serum cholesterol, and incr. appetite.
compare epinephrine and phenylephrine in the presence of an alpha blocker
epinephrine is beta > alpha; phenylephrine is a pure alpha agonist ( a1> a 2). Epi + an alpha blocker reverses the blood pressure effects of the drug- it reduces BP (beta agonist) instead of incr. BP (which is what is seen when its alpha effects predominate). Phenylephrine is a pure alpha agonist, so in the presence of an alpha blocker it basically leaves BP unchanged.
Beta blockers uses
angina pectoris, MI, supraventricular tachycardia, HTN, CHF, and glaucoma (timolol).
How do beta blockers redcue SVT? HTN?
SVT: reduces SVT by slowing AV conduction velocity- class II antiarrhythmic
HTN: reduces cardiac output, and reduces renin secretion d/t beta 1 receptor blockade of juxtoglomerular apparatus cells.
toxicity of beta blockers, contraindications
impotence, CV effects like bradycardia and AV block, CNS effects like seizures, sedation, sleep changes, dyslipidemia (esp. metoprolol), and exacerbation of COPD/asthma. small potential risk of masking hypoglycemia. avoid in cocaine used (risk of unopposed alpha-adrenergic receptor activity)
What are the beta-1 selective antagonists (example)
example: metoprolol. the mostly go from A to M (beta 1 is the first half of the alphabet)
What are the nonselective antagonists?
mostly go from N to Z. (propanolol, timolol, etc)
nonselective alpha AND beta antagonists
carvedilol, labetalol (have a modified suffix- not -olol