Exam 2 Drugs

Question 1

Carvedilol

Answer 1

Nonselective α and β blocker

Selectivity order: β₁ = β₂ ≥ α₁ > α ₂

Has dramatic results in CHF patients

Question 2

Propranolol

Answer 2

Nonselective β blocker

Selectivity order: β₂ = β₁ >>>> α

Major effect is to decrease work and O₂ demand of heart

Blocks sympathetic bronchodilation, so care must be used in asthmatics and COPDers

May mask the signs of hypoglycemia

Question 3

Prazosin

Answer 3

Selective α₁ blocker

Selectivity order: α₁ >>>>>>>> α₂

Used to treat HTN

Decreased incidence of reflex tachycardia

Syncope is a common side effect

Question 4

Phentolamine

Answer 4

Reversible α₁ and α₂ blocker (equal selectivity for both)

Used in treatment of pheochromocytoma

Associated with lots of reflex tachycardia from α₂ inhibition (results in increased NE release)

Question 5

Phenylephrine

Answer 5

α₁ selective agonist

Selectivity order: α₁ > α₂ >>>> β

Used as a pressor agent with minimal effect on cardiac tissue (no β₁ effects), ex to support BP during surgery

Causes increases in vasoconstriction, TPR, and BP

Increase in BP will cause reflex bradycardia

Question 6

Dobutamine

Answer 6

β₁ selective agonist

Selectivity order: β₁ > β₂ >> α

Used to support cardiac function post MI or in CHF

Effects: +inotropy, increased CO, some increase in HR

Question 7

Isoproterenol

Answer 7

Nonselective β agonist

Selectivity order: β₁ = β₂ >>>>> α

Main β₁ effect: increased HR and contractility

Question 8

Norepinephrine

Answer 8

Sympathomimetic

Selectivity order: α₁ = α₂ , β₁ >> β₂

Almost no β₂ effect

Direct effects on heart: positive inotropic and chronotropic via β₁

Indirect effect: reflex bradycardia (from increased BP) - blocked by atropine

On vessels, acts as a pressor through α₁ mediated vasoconstriction (increased BP)

Question 9

Epinephrine

Answer 9

Sympathomimetic

Selectivity: α₁ = α₂ , β₁ = β₂

Higher affinity for β₂ than α₁ , but stronger effect at α₁

Increases chronotropy, inotropy, conduction velocity, work of heart, and O₂ consumption

At low doses, β₂ effect predominates, causing vasodilation and decreasing BP

At higher doses, α₁ effect predominates, causing vasoconstriction and increasing BP

Question 10

Albuterol

Answer 10

β₂ selective agonist

Selectivity: β₂ >> β₁ >>>>>> α

Used to treat bronchospasm

Question 11

Atropine

Answer 11

mAChR antagonist

Used to increase HR by blocking vagal tone

At low doses, initial decrease in HR observed before vagal block sets in

Question 12

Bethanechol

Answer 12

Direct acting selective mAChR agonist

Primarily affects urinary and GI tracts

Used to treat urinary retention, heartburn, etc.

Little cardiac effect

Not affected by cholinesterase

Question 13

Methacholine

Answer 13

Direct acting selective mAChR agonist

No nicotinic activity

Used in diagnosis of bronchial airway hyperreactivity

Little susceptibility to cholinesterase

Question 14

Cardioselective β-blockers

Answer 14

Metoprolol and Atenolol

Selectivity: β₁ >> β₂

Indicated in stable CHF pts