Tài liệu CLINICAL PHARMACOLOGY 2003 (PART 25A) pptx

23

Arterial hypertension, angina

pectoris, myocardial infarction

SYNOPSIS

Hypertension and coronary heart disease

(CHD) are of great importance. Hypertension

affects above 20% of the total population of the

USA with its major impact on those over age

50. CHD is the cause of death in 30% of males

and 22% of females in England and Wales.

Management requires attention to detail, both

clinical and pharmacological.

The way drugs act in these diseases is

outlined and the drugs are described according

to class.

• Hypertension and angina pectoris: how

drugs act

• Drugs used in both hypertension and angina

Diuretics

Vasodilators

organic nitrates, calcium channel

blockers.ACE inhibitors, angiotensin II￾receptor antagonists

Adrenoceptor blocking drugs, and (

Peripheral sympathetic nerve terminal

Autonomic ganglion-blocking drugs

Central nervous system

Treatment of angina pectoris

• Acute coronary syndromes and myocardial

infarction

• Arterial hypertension

• Sexual function and cardiovascular drugs

• Phaeochromocytoma

Hypertension: how

drugs act

Consider the following relationship:

Blood pressure =

cardiac output x peripheral resistance

Therefore drugs can lower blood pressure by:

• Dilatation of arteriolar resistance vessels.

Dilatation can be achieved through direct

relaxation of vascular smooth muscle cells, by

stimulation of nitric oxide (NO) production, or

by blocking (suppressing) endogenous

vasconstrictors, noradrenaline (norepinephrine)

and angiotensin.

• Dilatation of venous capacitance vessels; reduced

venous return to the heart (preload) leads to

reduced cardiac output, especially in the upright

position

• Reduction of cardiac contractility and heart rate.

• Depletion of body sodium. This reduces plasma

volume (transiently), and reduces arteriolar

response to noradrenaline (norepinephrine)

Modern antihypertensive drugs lower blood

pressure with minimal interference with homeo￾static control, i.e. change in posture, exercise.

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