CIS: Adrenergic Drugs

Question 1

Dilation of vessels in skeletal muscle

Answer 1

B2

Question 2

Does vasculature receive sympathetic information?

Does it receive parasympathetic information?

Answer 2

Yes

No! PARASYMPATHETICS DOES NOT AFFECT BV

Question 3

Tyramine affects NE how? If tyramine does not affect BP, there is degeneration of the ________

Answer 3

Increases release of NE from the post-ganglionic neuron => receptor on the effector organ

post-ganglionic neuron

Question 4

Does NE act on post-ganglionic neuron?

Answer 4

No.

ACh is release from pre-ganglionic neuron and binds to nicotenic receptors on the post-ganglionic neuron.

NE is released from the post and acts on effector organs

Question 5

Want mydriasis but not alter normal control of accommodation; which one will dilate the pupil without altering accommodation?

Answer 5

Phenylephrine

Question 6

How can we dilate the pupil?

Answer 6

1. M3 ANT: mydriasis and accommodation
2. Alpha 1 AGO: Mydriasis

Question 7

How does phentalomine cause miosis?

Answer 7

Phentolamine is a non-selective alpha ANT. Normally, A1 dilates the pupil. If we block it, it will constrict and cause miosis.

Question 8

Atropine affects the eye how?

Answer 8

M3 ANT

Mydriasis

Stop accomodation

Question 9

What causes accomodation?

Answer 9

+M3 receptor => contract ciliary muscle

Question 10

Describe the affects of NE on BP and HR.

Answer 10

NE: increase BP => arteries are stretched => baroreceptors are activated => decrease HR (bradycardia) and reduce sympathetic tone to vasodilate and try to reduce the BP to prevent high increases.

Question 11

What happens if we give NE and then atropine?

Answer 11

• Atropine (muscarinic ANT): blocks vagal influences on heart => prevents decreases in HR => increase HR
  
  • counteracts the decrease in HR caused by NE

Question 12

Which would work to tx acute heart failure if we cannot use dobutamine?

Answer 12

NE + phentolamine

• Dobutamine has potent INOTROPIC action ans ia used in acute heart failure to stimulate cardiac function
• NE (alpha1-2 AND B1 AGO) will + B1, but you will see a increase in BP. To offset that increase in BP, give it with phentolamine (alpha ANT), it will 0 out the actions of alpha receptors and only + B1.

Question 13

Drug-induced hypotension; taking antihypertensive drug for many months; not volume depleted; you give phenylephrine at the same dose–>no change in BP; which drug did the pt most likely take an overdose of?

Answer 13

Giving the pt phenylephrine to try to engage alpha1 receptors, so something must block alpha1 receptors

THUS: prazosin

Question 14

How does phentolamine affect HR

Answer 14

tachycardia is not a direct effect of phentolamine, but the drop in BP will inhibit the baroreflex and cause tachycardia via release of NE

Question 15

What can block the BP fall caused by phenotolamine

Answer 15

Propranolol can block this BP falls from vasodilation caused by alpha blocker