Blood pressure pharmacology

Question 1

Hexamethonium (and pentamethonium)

Answer 1

Non-depolarising block at the autonomic ganglia leads to passive relaxation of peripheral smooth muscle, so drop in peripheral resistance.

Question 2

Enalapril, captopril, ramipril.

Answer 2

An ACE inhibitor (interacts with a sulphydryl moiety), prevents conversion of angiotensin I to angiotensin II. Reduces peripheral resistance and sodium retention.

Question 3

Losartan

Answer 3

Angiotensin receptor blockers. Similar to ACE inhibitors, block peripheral vasoconstriction and sodium retention via AT1 receptors.

Question 4

Aliskerin

Answer 4

Blocks binding of renin so cannot form angiotensin I.

Question 5

Dihydropyridines (nifedipine and amlodipine)

Answer 5

Calcium channel blocker (particularly in vasculature), prevents vasoconstriction.

Question 6

Pheylalkylamines (verapamil)

Answer 6

Calcium channel blocker (particularly in heart)

Question 7

Thiazide diuretics (bendrofluazide)

Answer 7

Compete for Cl binding site at the Na/Cl transporter in the DCT. So prevent Na and hence water reabsorption.

Question 8

Beta blockers (propranolol)

Answer 8

Beta 1 adrenergic receptors in the kidney reduce renin release. Also can reduce effects in CNS sympathetic outflow. Cardioselective = atenolol.

Question 9

Prazosin

Answer 9

Alpha 1 adrenergic antagonist

Question 10

Hydralazine

Answer 10

Activates K+ ATP channels to block IP3 evoked Ca2+ release = primarily arterial vasodilator.