alpha blockers

Question 1

List the alpha blockers

Answer 1

Phenoxybenzamine, Phentolamine, Doxazoisn, Terazosin, Prazosin

Question 2

what are alhpa 2 receptors and what do they do?

Answer 2

They receive alpha 2, they are on the presynaptic neuron and when activated, they have a negative feedback mechanism on NE release

Question 3

what are alpha 1 receptors and what do they do?

Answer 3

they receive alpha 1, they are on the post-synaptic neuron and when activated, they increase IP3 and DAG resulting in increase in intracellular Ca2+

Question 4

If a patient is on an alpha blocker and is administered epinephrine what will happen to BP?

Answer 4

It will go down because the epinepherine will bind to beta receptors in skeletal muscle and cause vasodilation

Question 5

If a patient is on an alpha blocker and is administered NE what will happen to BP?

Answer 5

it will increase but not as much because NE has a strong affinity for alpha receptors and not as much of an affinity for beta receptors

Question 6

These alpha blockers have a strong sensitivity for alpha 1 receptors

Answer 6

Terazosin, Doxazosin, Prazosin

Question 7

This alpha blocker has somewhat of a sensitivity for alpha 1

Answer 7

Phenoxybenzamine

Question 8

This alpha blocker has equal sensitivity for both alpha 1 and alpha 2 receptors

Answer 8

Phentolamine

Question 9

this alpha blocker is slightly alpha 1 selective, is long acting & irreversible, and it treats pheochromocytoma

Answer 9

Phenoxybenzamine

Question 10

this alpha blocker is equally sensitive to alpha 1 and alpha 2 and it treats pheochromocytoma and HTN emergency

Answer 10

Phentolamine

Question 11

What happens to BP if phentolamine is given at low doses?

Answer 11

increase BP because it will bind & BLOCK more to alpha 2 receptors thus increasing NE activity “positive inotrophic effect predominates”

Question 12

What happens to BP if phentolamine is given in high doses?

Answer 12

lowers BP because at high doses, phentolamine will bind & BLOCK more to alpha 1 receptors thus inhibiting the activity of NE and decreasing the amount of NE “vasodilatory effect dominates”

Question 13

adverse effects of alpha blockers?

Answer 13

first dose hypotension and reflex tachycardia

Question 14

these alpha blockers treat BPH

Answer 14

terazosin, doxazosin

Question 15

effects of alpha blockers on cholesterol?

Answer 15

increase HDL and decrease LDL

Question 16

which alpha blocker has serotonin receptor blocking effects and antihistaminic effects?

Answer 16

Phenoxybenzamine

Question 17

severe HTN from illicit drug overdose can be treated with?

Answer 17

alpha blockers

Question 18

this alpha blocker is sometimes used to treat possible tissue ischemia with the injection of NE

Answer 18

Phentolamine

Question 19

are alpha blockers used as a monotherapy?

Answer 19

No, ALLHAT study

Question 20

alpha 1 activation leads to?

Answer 20

vasoconstriction, GI relaxation, mydriasis (dilation of pupil)

Question 21

alpha 2 activation leads to?

Answer 21

inhibition of release of NE from presynaptic neurons, inhibit insulin release, platelet aggregation

Question 22

alpha 1 receptors are like which muscarinic receptor?

Answer 22

Like M1; they both increase IP3, DAG, intracellular Ca2+

Question 23

alpha 2 receptors are like which muscarinic receptor?

Answer 23

Like M2; they both inhibit adenylate cyclase thus decreasing cAMP