Pharmacology Autonomic Nervous System Pharmacology 3

Question 1

Clonidine is used to treat hypertension. What is its primary mechanism?

Accepted Answer

Stimulates central alpha-2 receptors reducing sympathetic outflow

Answer

Clonidine activates alpha-2 receptors in the brainstem (locus coeruleus), reducing sympathetic outflow and lowering blood pressure.

Question 2

A patient receives organophosphate poisoning. Which drug reverses the muscarinic effects?

Accepted Answer

Atropine

Answer

Atropine competitively blocks muscarinic receptors and reverses bronchospasm, excessive secretions, and bradycardia in organophosphate poisoning.

Question 3

Which effect distinguishes norepinephrine from epinephrine at clinical doses?

Accepted Answer

Norepinephrine has no beta-2 effect and causes reflex bradycardia

Answer

Norepinephrine lacks significant beta-2 activity, so it raises both systolic and diastolic pressure without vasodilation, triggering a baroreceptor-mediated reflex bradycardia.

Question 4

Ipratropium is preferred over atropine for COPD bronchodilation because it:

Accepted Answer

Is inhaled and poorly absorbed systemically, reducing side effects

Answer

Ipratropium is a quaternary ammonium compound that is poorly absorbed after inhalation, providing local bronchodilation with minimal systemic anticholinergic effects.

Question 5

Cocaine blocks the reuptake of norepinephrine. This causes:

Accepted Answer

Hypertension, tachycardia, and mydriasis

Answer

By blocking norepinephrine reuptake, cocaine increases sympathomimetic tone, causing hypertension, tachycardia, and pupil dilation.

Pharmacology Practice Test

Pharmacology Practice Test

Pharmacology Autonomic Nervous System Pharmacology 3