alpha and beta blockers

Question 1

phenoxybenzamine: use, mechanism, side effects

Answer 1

irreversible alpha blocker. used preoperatively for a pheochromocytoma to prevent a hypertensive crisis. may cause orthostatic hypotension and reflex tachycardia.

Question 2

phentolamine: use, mechanism, side effects

Answer 2

reversible alpha blocker that can be given to pts on MAO inhibitors who eat tyramine-containing foods

Question 3

What drugs are used to treat urinary symptoms of BPH and hypertension?

Answer 3

alpha 1 selective blockers. all end in -osin. (prazosin, terazosin, doxazosin, tamsulosin).

Question 4

What is one use of specific use of prazosin?

Answer 4

may be used for PTSD in addition to use for urinary symptoms of BPH and hypertension

Question 5

Side effect of prazosin

Answer 5

first dose orthostatic hypotension, dizziness, headache. also seen with terazosin, doxazosin, etc.

Question 6

mirtazapine mechanism and use

Answer 6

alpha-2 selective blocker. used to treat depression but may casue sedation, incr. serum cholesterol, and incr. appetite.

Question 7

compare epinephrine and phenylephrine in the presence of an alpha blocker

Answer 7

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.

Question 8

Beta blockers uses

Answer 8

angina pectoris, MI, supraventricular tachycardia, HTN, CHF, and glaucoma (timolol).

Question 9

How do beta blockers redcue SVT? HTN?

Answer 9

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.

Question 10

toxicity of beta blockers, contraindications

Answer 10

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)

Question 11

What are the beta-1 selective antagonists (example)

Answer 11

example: metoprolol. the mostly go from A to M (beta 1 is the first half of the alphabet)

Question 12

What are the nonselective antagonists?

Answer 12

mostly go from N to Z. (propanolol, timolol, etc)

Question 13

nonselective alpha AND beta antagonists

Answer 13

carvedilol, labetalol (have a modified suffix- not -olol

Question 14

What is the antidote for beta blockes?

Answer 14

glucugon