c. Anti-hypertensive drugs.
d. Anti-anginal drugs.
e. Anti-arrhythmic drugs.
f. Anti-hyperlipidemic drugs.
These are drugs used to lower BP in hypertension. Hypertension is a very common disorder, particularly past middle age. It is not a disease in itself, but is an important risk factor for cardiovascular mortality and morbidity. The cutoff manometric reading between normotensives and hypertensives is arbitrary. For practical purposes
‘hypertension’ could be that level of BP at or above which long-term antihypertensive treatment will reduce cardiovascular mortality. have
defined it to be 140 mm Hg systolic and 90 mm Hg diastolic, though risk appears to increase even above 120/80 mm Hg. Epidemiological studies have confirmed that higher the pressure (systolic or diastolic or both) greater is the risk of
cardiovascular disease. Majority of cases are of essential (primary) hypertension, i.e. the cause is not known. Sympa-
thetic and renin-angiotensin systems (RAS) may or may not be overactive, but they do contribute to the tone of blood vessels and c.o. in hypertensives, as they do in normotensives. Many antihypertensive drugs interfere with these regulatory systems at one level or the other.
Antihypertensive drugs, by chronically lowering BP, may reset the barostat to function at a lower level of BP.
Antihypertensive drug therapy has been remarkably improved in the last 60 years. Different classes of drugs have received prominence with passage of time in this period. Before 1950
hardly any effective and tolerated antihypertensive was available. Veratrum and Sod. thiocyanate could lower BP, but were toxic and difficult to use. The ganglion blockers developed in the 1950s were effective, but inconvenient.
Reserpine was a breakthrough, but produced mental depression. The therapeutic potential of hydralazine could not be tapped fully because of marked side effects when it was used alone. Guanethidine introduced in 1961 was an improvement on ganglion blockers. The antihypertensives of
the 1960–70s were methyldopa, β blockers, thiazide and high ceiling diuretics and clonidine. The status of β blockers and diuretics was consolidated in the 1970s and selectiv α1 blocker prazosin broke new grounds. The antihypertensives of the 1980–90s are angiotensin II converting enzyme
(ACE) inhibitors and calcium channel blockers. Angiotensin receptor blockers (losartan, etc.) were added soon after,
and the direct renin inhibitor aliskiren is the latest drug. With the development of many types of drugs, delineation
of their long-term benefits and complications, and understanding of the principles on which to combine them, hypertension can now be controlled in most cases with minimum discomfort.
CLASSIFICATION
1. Diuretics
Thiazides: Hydrochlorothiazide,
Chlorthalidone, Indapamide
High ceiling:Furosemide, etc.
K+ Sparing: Spironolactone, Amiloride
2. ACE inhibitors
Captopril, Enalapril, Lisinopril,
Perindopril, Ramipril, Fosinopril, etc.
3. Angiotensin (AT1 receptor) blockers
Losartan, Candesartan, Irbesartan, Valsartan, Telmisartan
4. Direct renin inhibitor
Aliskiren
5. Calcium channel blockers
Verapamil, Diltiazem, Nifedipine, Felodipine, Amlodipine, Nitrendipine, Lacidipine, etc.
6. β Adrenergic blockers
Propranolol, Metoprolol, Atenolol, etc.
