CLINICAL PHARMACOLOGY 2003 (PART 25A)

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...
Nội dung trích xuất từ tài liệu:
CLINICAL PHARMACOLOGY 2003 (PART 25A) 23Arterial hypertension, anginapectoris, myocardial infarction SYNOPSIS Hypertension: how Hypertension and coronary heart disease (CHD) are of great importance. Hypertension drugs act affects above 20% of the total population of the USA with its major impact on those over age Consider the following relationship: 50. CHD is the cause of death in 30% of males Blood pressure = and 22% of females in England and Wales. cardiac output x peripheral resistance Management requires attention to detail, both clinical and pharmacological. Therefore drugs can lower blood pressure by: The way drugs act in these diseases is • Dilatation of arteriolar resistance vessels. outlined and the drugs are described according Dilatation can be achieved through direct to class. relaxation of vascular smooth muscle cells, by • Hypertension and angina pectoris: how stimulation of nitric oxide (NO) production, or drugs act by blocking (suppressing) endogenous • Drugs used in both hypertension and angina vasconstrictors, noradrenaline (norepinephrine) and angiotensin. Diuretics • Dilatation of venous capacitance vessels; reduced Vasodilators venous return to the heart (preload) leads to organic nitrates, calcium channel reduced cardiac output, especially in the upright blockers.ACE inhibitors, angiotensin II- position receptor antagonists • Reduction of cardiac contractility and heart rate. Adrenoceptor blocking drugs, and ( • Depletion of body sodium. This reduces plasma Peripheral sympathetic nerve terminal volume (transiently), and reduces arteriolar Autonomic ganglion-blocking drugs response to noradrenaline (norepinephrine) Central nervous system Treatment of angina pectoris Modern antihypertensive drugs lower blood pressure with minimal interference with homeo- • Acute coronary syndromes and myocardial static control, i.e. change in posture, exercise. infarction • Arterial hypertension • Sexual function and cardiovascular drugs • Phaeochromocytoma 461 23 A R T E R I A L H Y P E R T E N S I O N , A N G I N A P E C T O R I S, Ml vasoconstrictors, principally noradrenaline. WhileAngina pectoris: how this hyposensitivity may be a consequence of the sodium depletion, thiazides are generally more effec-drugs act tive antihypertensive agents than loop diuretics, despite causing less salt loss, and evidence suggestsAngina can be viewed as a problem of supply and an independent action of thiazides on an unidentifieddemand. Drugs used in angina pectoris are those ion-channel on vascular smooth muscle cell mem-that either increase supply of oxygen and nutrients, branes. Maximum effect on blood pressure is delayedor reduce the demand for these — or both. for several weeks and other drugs are best added Supply can be increased by: cardiac work and after this time. Adverse metabolic effects of thiazidesmyocardial oxygen need by: on serum potassium, blood lipids, glucose tolerance,• dilating coronary arteries and uric acid metabolism led to suggestions that• slowing the heart (coronary flow, uniquely, they should be replaced by newer agents not having occurs in diastole, which lengthens as heart rate these effects. It is, however, now recognised that falls). ...