Antihypertensive agents

Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke and myocardial infarction.

Antihypertensives are a class of drugs that are used in medicine and pharmacology to treat hypertension (high blood pressure). There are many classes of antihypertensives, which—by varying means—act by lowering blood pressure. Evidence suggests that reduction of the blood pressure by 5-6 mmHg can decrease the risk of stroke by 40%, of coronary heart disease by 15-20%, and reduces the likelihood of dementia, heart failure, and mortality from cardiovascular disease.

Which type of medication to use initially for hypertension has been the subject of several large studies and resulting national guidelines. The fundamental goal of treatment should be the prevention of the important “endpoints” of hypertension such as heart attack, stroke and heart failure. Several classes of medications are effective in reducing blood pressure. However, these classes differ in side effect profiles, ability to prevent endpoints, and cost. The choice of more expensive agents, where cheaper ones would be equally effective, may have negative impacts on national healthcare budgets.^[1]

In the United States, the JNC7 (The Seventh Report of the Joint National Committee on Prevention of Detection, Evaluation and Treatment of High Blood Pressure) recommends starting with a thiazide diuretic if single therapy is being initiated and another medication is not indicated.^[2] This is based on a slightly better outcome for chlortalidone in the ALLHAT study versus other anti-hypertensives and because thiazide diuretics are relatively cheap.^[3] A subsequent smaller study (ANBP2) published after the JNC7 did not show this small difference in outcome and actually showed a slightly better outcome for ACE-inhibitors in older male patients.^[4]

Despite thiazides being cheap, effective, and recommended as the best first-line drug for hypertension by many experts, they are not prescribed as often as some newer drugs. Arguably, this is because they are off-patent and thus rarely promoted by the drug industry.^[5]

In the United Kingdom, the June 2006 “Hypertension: management of hypertension in adults in primary care”^[6] guideline of the National Institute for Health and Clinical Excellence, downgraded the role of beta-blockers due to their risk of provoking type 2 diabetes.^[7]

References

1. ^ Nelson MR, McNeil JJ, Peeters A et al (Jun 4 2001). “PBS/RPBS cost implications of trends and guideline recommendations in the pharmacological management of hypertension in Australia, 1994-1998”. Med J Aust 174 (11): 565-8.
   PMID 11453328.
2. ^ a b
   c Chobanian AV et al (2003). “The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report“. JAMA 289: 2560-72.
   PMID 12748199.
3. ^ ALLHAT Officers and Coordinators for the ALLHAT Collaborative Research Group (Dec 18 2002). “Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)“. JAMA 288 (23): 2981-97.
   PMID 12479763.
4. ^ Wing LM, Reid CM, Ryan P et al (Feb 13 2003). “A comparison of outcomes with angiotensin-converting–enzyme inhibitors and diuretics for hypertension in the elderly“. NEJM 348 (7): 583-92.
   PMID 12584366.
5. ^ Wang TJ, Ausiello JC, Stafford RS (1999). “Trends in Antihypertensive Drug Advertising, 1985–1996“. Circulation 99: 2055-2057.
   PMID 10209012.
6. ^
   Hypertension: management of hypertension in adults in primary care (PDF). National Institute for Health and Clinical Excellence. Retrieved on 2006-09-30.
7. ^ Sheetal Ladva (28/06/2006).
   NICE and BHS launch updated hypertension guideline. National Institute for Health and Clinical Excellence. Retrieved on 2006-09-30.

1. Herbals Affecting Blood Pressure [Herbal Provoking Hypotension; Clark (2003) AAFP Board Review, Seattle ]

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