Pharmacology of Beta Receptors

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What is the effect of stimulating α2-receptors on blood pressure?

No change
Decrease (correct)
Initial decrease followed by increase
Increase

What is the effect of β2 receptors on respiratory smooth muscle?

Relaxation (correct)
Constriction
Depends on dose
No change

What is the effect of dopamine on heart rate at low doses?

Decrease (correct)
Increase
Biphasic response
No change

What is the primary mechanism of epinephrine's effect on coronary blood flow?

Increased myocardial oxygen demand (C) Signup and view all the answers

What is the primary effect of β1-receptors on the heart?

Positive chronotropy and inotropy (C) Signup and view all the answers

What is the half-life of elimination of epinephrine?

< 5 minutes (C) Signup and view all the answers

What is the effect of norepinephrine on heart rate?

Maintained (A) Signup and view all the answers

What is the primary mechanism of dopamine's indirect effects?

Release of norepinephrine (D) Signup and view all the answers

What is the effect of isoproterenol on myocardial O2 supply?

Decreased (D) Signup and view all the answers

What is the primary effect of dobutamine on the heart?

Increased coronary blood flow (A) Signup and view all the answers

What is the mechanism of norepinephrine's vasoconstrictor effect?

Activation of α1 receptors (B) Signup and view all the answers

What is the effect of dopamine on peripheral vascular resistance at high doses?

Increased (D) Signup and view all the answers

What is the primary effect of β1 agonists on the heart?

Increase cardiac contractility (C) Signup and view all the answers

What is the mechanism of action of ephedrine?

Indirect β agonist and direct α agonist (C) Signup and view all the answers

What is the primary effect of phenylephrine on the heart?

Decrease heart rate (C) Signup and view all the answers

What is the primary mechanism of action of phentolamine?

Competitive and nonselective α antagonist (B) Signup and view all the answers

What is the typical dose range for dopamine infusion?

0.5-1 mcg/kg/min (C) Signup and view all the answers

What is the primary use of phenylephrine nasal drops/spray?

To vasoconstrict nares prior to nasal intubation (A) Signup and view all the answers

What is the primary effect of phenoxybenzamine on blood pressure?

It causes a decrease in blood pressure (B) Signup and view all the answers

What is the main use of yohimbine?

Treatment of orthostatic hypotension (D) Signup and view all the answers

What is the FDA warning associated with droperidol?

Prolonged QT interval (C) Signup and view all the answers

What is the effect of clonidine on heart rate?

It decreases heart rate in a dose-dependent manner (A) Signup and view all the answers

What is the main mechanism of action of dexmedetomidine?

It is a selective presynaptic α2 agonist (B) Signup and view all the answers

What is the effect of phenoxybenzamine on insulin secretion?

It increases insulin secretion (A) Signup and view all the answers

What is the primary indication for initiating β blockade preoperatively?

Vascular and intermediate-risk surgical procedures (D) Signup and view all the answers

What is the primary advantage of using cardioselective β blockers?

They are more selective for β1 receptors (C) Signup and view all the answers

What is the effect of β blockers on the sympathetic nervous system?

Decrease sympathetic nervous system activity (B) Signup and view all the answers

What is the dose of esmolol for controlling heart rate?

10-20 mg initial and titrate to goal HR (D) Signup and view all the answers

What is the mechanism of labetalol's action?

Non-selective β and α1 antagonist (C) Signup and view all the answers

What is the antidote for β blocker overdose?

Glucagon 5 mg IV (A) Signup and view all the answers