Antihypertensives

Question 1

What is blood pressure?
What is the unit of measurement?
What are diastole and systole?

Answer 1

force of blood against the walls of blood vessels.
millimeters of mercury (mmHg).
Phases of the cardiac cycle.
systole: when heart contracts to pump blood out
diastole: when heart relaxes

Question 2

What are the blood pressure categories?

Answer 2

Normal < 120/80
Elevated 120-129 / <80
Hypertension stage 1 130-139 / 80-89
Hypertension stage 2 >140/90
Hypertensive crisis > 180/120

Question 3

What are antihypertensive drugs?

Answer 3

class of drugs that are used to treat hypertension
1) ENDOTHELIN RECEPTOR ANTAGONISTS

Question 4

What are the Forms of Hypertension?

Answer 4

1) Primary (essential): most common
2) Renal hypertension: experimentally narrowing arteries of animals.
3) pheochromocytoma: tumors in adrenal medulla that release catecholamines.
4) Pulmonary arterial hypertension (PAH): increases bp in arteries of lungs. Treat with Ambrisentan , Sitaxsentan and Bosentan

Question 5

ENDOTHELIN RECEPTOR ANTAGONISTS
MOA
TYPES
EXAMPLES

Answer 5

endothelin 1 is a peptide made in vascular endothelium that regulates smooth muscle contraction.
The antagonists bind to ETa and ETb receptors blocking endothelin

1) Propanoic Acid Derivative: Ambrisentan
2) Sulfonamide Class ETRA : Bosentan, Sitaxsentan

Sitaxentan and Ambrisentan are selective for the ETA receptor.
Bosentan is a dual antagonist

Question 6

SELECTIVE ALPHA ADRENERGIC ANTAGONISTS

use
Moa
example

Answer 6

treat catecholamine-dependent hypertension

Alpha-1 antagonists block the alpha-1 adrenergic receptors preventing vasoconstriction without interfering with the alpha-2 receptors

Doxazosin treats hypertension associated with conditions like pheochromocytoma

Question 7

CENTRALLY ACTING ADRENERGIC AGENTS
MOA
EXAMPLE

Answer 7

stimulate alpha-2 receptors in the central nervous system.
reduces sympathetic outflow (the body’s “fight or flight” response) resulting in a hypotensive effect

Clonidine Hydrochloride is metabolized in the body to form two major metabolites: p-hydroxyclonidine ( does not cross the blood-brain barrier and therefore does not contribute to the hypotensive effect ) and its glucuronide.

Question 8

VASODILATORY DRUGS ACTING ON SMOOTH MUSCLE
types

Answer 8

Direct-Acting Vasodilators act directly on the vascular smooth muscle.
e.g. hydralazine hydrochloride, sodium nitroprusside, potassium channel openers, calcium channel-blocking agents

Indirect-Acting Vasodilators interfere with vasoconstrictor stimuli
e.g sympatholytic drugs: reserpine
alpha-adrenergic antagonists: prazosin hydrochloride ACEinhibitors
angiotensin II receptor antagonists: saralysin

Question 9

PHOSPHODIESTERASE TYPE 5
INHIBITORS
moa
examples
ci

Answer 9

Phosphodiesterase type 5 (PDE5) is responsible for the catalytic hydrolysis of cGMP in the smooth muscle of the arteries in the penis and lungs.

Inhibitors relax arteries in the penis and lungs
Tadalafil , sildenafil

CYP3A4 Inhibitors :ritonavir, indinavir, ketoconazole, erythromycin can increase tadalafil plasma levels by inhibiting the enzyme that metabolizes it.
potentially enhancing its effects or increasing the risk of side effects.