Antihypertensive combination therapy.
The rationale behind employing combination antihypertensive therapy stems from growing evidence that there is a greater need for more aggressive control of systemic arterial pressure to levels below what we have traditionally accepted (140/90 mmHg), and that we have had historically poor control rates with existing approaches to antihypertensive therapeutics. Single agent therapeutic approaches result in only a 40-50% control rate after 6 months of therapy, illustrating that there is a dramatically high rate of discontinuation of antihypertensive drugs in clinical practice. These poor results suggest that there are issues about inadequate education, insufficient efficacy or poor tolerability for which we need to be concerned. Consequently, efforts are under way to reapproach antihypertensive care by focusing on the need for improved education, as well as to reevaluate the traditional teaching of starting with one drug and titrating it upward until an adequate clinical response is achieved. The problem with the latter approach is that it frequently results in an increased incidence of adverse events which interfere with patient tolerability and compliance. Utilization of lower doses of two or more agents may provide satisfactory reduction of blood pressure without the increased risk of adverse events with higher doses of the individual monotherapies. Moreover, there may be complimentary, additive, or even synergistic effects of two drugs working together by different mechanisms. Therefore, a low-dose therapeutic combination may represent an optimal approach, not only for patients unresponsive to higher doses of individual monotherapies, but perhaps also to initiate treatment.