Antihypertensive drugs problems with

Adding extra potassium to the diet is a great idea for practically everyone who wants to lower his or her blood pressure, but there are exceptions. Don t do so if you have kidney problems or if you are currently taking the antihypertensive drugs called ACE inhibitors. If you have any doubts, talk with your doctor about the advantages and disadvantages of the potassium boost. 

Never forget that you are in partnership with your physician, that you have a say in the decision-making process, and that ultimately you will play a major role in your own health destiny. It is ironic that people will be more selective in choosing an auto mechanic than a physician You owe it to yourself and your loved ones to find a doctor with whom you can establish an excellent personal relationship. Does your doctor fully answer your questions, consider your special needs and problems, and leave you with a sense of confidence If not, find another doctor If you have hypertension, controlling that condition will be a lifelong endeavor. And if you require antihypertensive drugs, a great deal of effort will... 

When problems do arise they usually reflect either interactions, which with caution could have been avoided, or relative overdosage. In the course of time the recommended antihypertensive doses of diuretics have been reduced, and some adverse effects that were noted in the early years are now of less significance these include hypotension, dehydration, reduction of the glomerular filtration rate, and severe hypokalemia. Continued use of thiazides in excessive doses may reflect ignorance of their very flat dose-response curve (1). At currently recommended low doses, diuretics improve overall quality of life, even in asymptomatic patients with mild hypertension (2). The large HANE study (3) provided no evidence of superior efficacy or tolerability of new classes of antihypertensive drugs. 

Rose M, McMahon FG (1990) Some problems with antihypertensive drug studies in the context of the new guidelines. American Journal of Hypertension 3 151-155. 

To circumvent problems, encourage patient compliance, avoid excessive doses, avoid combining sympatholytics and -blockers, and maintain antihypertensive medication in surgical patients. When discontinuing medication, taper the dose slowly, one drug at a time use special caution in patients with coronary artery or cerebrovascular disease. 

The hemodynamic effects of diazoxide are similar to those of hydralazine and minoxidil. It produces direct relaxation of arteriolar smooth muscle with little effect on capacitance beds. Since it does not impair cardiovascular reflexes, orthostasis is not a problem. Its administration is, however, associated with a reflex increase in cardiac output that partially counters its antihypertensive effects. Propranolol and other -blockers potentiate the vasodilating properties of the drug. Diazoxide has no direct action on the heart. Although renal blood flow and glomerular filtration may fall transiently, they generally return to predrug levels within an hour. 

The reduction in plasma volume produced by p-blockers contrasts with the increased volume seen with other types of antihypertensives. Tolerance to the antihypertensive actions of p-blockers therefore is less of a problem than with the vasodilating drugs. An additional difference from the vasodilators is that plasma renin activity is reduced, rather than increased, by propranolol (Inderal). Orthostatic hypotension does not occur with p-blockers. 

Although dizziness is a fairly frequent complaint at the beginning of diuretic treatment (1), postural hjrpotension is rarely reported. Ischemic complaints (mesenteric infarction and transient cerebral ischemic attacks) have been observed in elderly patients, but it is not clear whether these resulted from diminished organ perfusion or from an effect of the drug itself. The former is more likely, since similar problems have arisen with any form of antihypertensive treatment in old people who have to some degree become dependent on their hypertension to ensure a blood supply through sclerotic vessels. 

Three points are apparent from this story. First, targets in a given family do tend to prefer structurally related compounds. Second, even the most difficult problems can eventually be overcome given sufficient incentive. And third, our original point that market space does exist for drugs with novel mechanisms of action MOAs). Now that aliskiren has made it to market, both single agent and combination use with other antihypertensives can be expected to provide a win-win situation for its maker, Novartis. 

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