Place des diuretiques a faibles doses dans le traitement de l'hypertension arterielle

Improvements in the management of hypertension are clearly needed in view of the current evidence that only about one-fourth of patients with hypertension are being adequately treated. Specific guidelines recommended in the sixth report of the US Joint National Committee (JNC-VI) should help practitioners provide effective therapy to a much larger proportion of patients. These guidelines include the more widespread use of lifestyle modifications, including smoking cessation, moderate sodium restriction, weight loss and regular aerobic exercise. For those patients who are at relatively low overall risk of cardiovascular disease, such lifestyle modifications are recommended as sole therapy for 6 to 12 months, even if the blood pressure is as high as 160/100 mmHg. On the other hand, immediate institution of antihypertensive drug therapy is recommended for those at relatively high risk even if blood pressure is as low as 130/85 mmHg. This includes all patients with diabetes, and those with renal insufficiency or congestive heart failure. The initial choice of drug therapy should be based upon the absence or presence of certain compelling indications for specific drugs or a variety of comorbid conditions that favour certain drugs. On the basis of multiple randomised controlled trials, diuretics and, to a lesser degree, β-blockers are recommended for those with uncomplicated hypertension. Diuretics are also preferred for elderly individuals with isolated systolic hypertension and are indicated for a variety of comorbid conditions, including heart failure, type 2 diabetes and osteoporosis. On the basis of recent randomised controlled trials in the elderly, the dosage of diuretics should be kept low, equivalent to as little as 6.25 mg of hydrochlorothiazide when given in combination with other agents, or 12.5 to 25 mg when used alone. The biochemical alterations seen with higher doses of diuretics can thus be avoided, enabling the full cardioprotective effects to be provided. The JNC-VI report further emphasises the need to add a diuretic to any other class of agent chosen as initial therapy if a full therapeutic response is not achieved. This need for a diuretic reflects in part the tendency for renal sodium retention when the blood pressure is lowered with non-diuretic agents. The addition of a low dose of diuretic will enhance the therapeutic efficacy of all other classes of drugs. Lastly, JNC-VI emphasises the critical importance of using drugs that provide continued efficacy over the entire 24-hour period when given once daily. Compliance with therapy will thus be improved and protection provided against cardiovascular catastrophes that occur predominantly during the early morning hours.