Mono- and combination therapy with felodipine or enalapril in elderly patients with systolic hypertension

Candesartan and hydrochlorothiazide in isolated systolic hypertension

AIM

We investigated the efficacy and safety of daily candesartan 8/16mg and hydrochlorothiazide 12.5 mg as monotherapy and in combination in older patients with systolic hypertension.

METHODS

The study used a double-blind randomized placebo-controlled crossover design. Treatment phases were of 6 weeks duration. For inclusion, patients were aged 55-84 years with sitting systolic blood pressure (SBP) 160-210 mmHg and diastolic blood pressure (DBP) < 95 mmHg. Nineteen patients (11 male, eight female, median age 68 years) completed the study.

MAJOR FINDINGS

Compared with the placebo phase, clinic and ambulatory SBP was significantly reduced with both dose-adjusted candesartan and fixed-dose hydrochlorothiazide as monotherapy, the effect of candesartan being greater than that of hydrochlorothiazide. In combination, the effects of the two drugs were additive. Both drugs were well tolerated either as monotherapy or in combination.

CONCLUSION

Both candesartan and a low dose of hydrochlorothiazide are effective and well-tolerated antihypertensive agents in isolated systolic hypertension with additive effects in combination. Candesartan was more effective than hydrochlorothiazide, although it is possible that dose adjustment only of candesartan could have enhanced its relative effectiveness.

Calcium channel blockade in combination with angiotensin-converting enzyme inhibition or angiotensin II (AT(1)-receptor) antagonism in hypertensive diabetics and patients with renal disease and hypertension

Effective reduction in blood pressure (BP) improves survival and morbidity in hypertensive patients. Combination therapy with multiple antihypertensive agents is frequently required in clinical practice and therapeutic trials to achieve target BP. Patients at elevated cardiovascular risk achieve the greatest benefit from equivalent reduction in BP and also require more stringent BP control. In patients with hypertension and diabetes mellitus or renal disease, BP control is of primary importance and blockade of the renin-angiotensin system (RAS) should be the initial therapeutic intervention. Choice of combination therapy has been insufficiently studied in major clinical cardiovascular endpoint trials. Diuretic therapy remains the logical addition to RAS blockade. Despite previous debate, the available evidence suggests long-acting calcium-channel blockers are also a safe and very effective addition to improve BP control further. The choice of antihypertensive combination therapy should not override the fundamental necessity of lowering BP to target levels.

Low-dose diuretic and/or dietary sodium restriction when blood pressure is resistant to ACE inhibitor

AIM

To compare the efficacy of indapamide (1.25 mg daily) and low-salt diet (<100 mmol/day) separately and in combination in essential hypertensive patients with inadequate BP response to perindopril.

DESIGN AND METHODS

Randomized double-blind, double-dummy, crossover design. The randomized treatments were indapamide 1.25 mg daily, sodium chloride 80 mmol daily, the combination of indapamide and sodium chloride and placebo. All patients received perindopril 4 mg daily and maintained a low-sodium diet.

RESULTS

19 patients entered and 17 completed the study. Prior to randomization, average clinic sitting blood pressure was 162/101 mm Hg and average 24-h urine sodium excretion was 157 mmol/day. Compared to the phase in which patients received perindopril with sodium repletion, clinic and ambulatory BPs were significantly reduced (p<0.01) in all the other phases. Indapamide had a greater effect on BP than dietary sodium restriction, and in combination their effects were additive. The effect of indapamide on ambulatory BP persisted throughout 24 h, but the effect of the low-salt diet was predominantly observed during waking hours.

CONCLUSIONS

In hypertensives with BP resistant to the angiotensin converting enzyme (ACE) inhibitor perindopril, the diuretic indapamide had greater additional efficacy and longer duration of action than dietary sodium restriction. In combination they had additive effects on BP.

Lacidipine, hydrochlorothiazide and their combination in systolic hypertension in the elderly

OBJECTIVE

To compare with placebo the efficacies of once-daily administrations of lacidipine and hydrochlorothiazide separately and in combination to elderly patients with systolic hypertension.

DESIGN AND METHODS

Nineteen elderly subjects (five men and 14 women, median age 71 years, range 62-79 years) participated in the study, which had a randomized double-blind crossover design. For each subject there were four treatment phases, each of duration 4 weeks. The initial treatments in each phase were 2 mg lacidipine once a day and 25 mg hydrochlorothiazide once a day, separately and in combination, and placebo. Doses of each agent could be doubled after 2 weeks in each phase if the patient's goal systolic blood pressure had not been achieved. The numbers of subjects administered the higher dose of each treatment were 13 for placebo, 14 for lacidipine, 11 for hydrochlorothiazide and eight for lacidipine plus hydrochlorothiazide.

RESULTS

End-of-phase mean clinic blood pressures were 164/85 mmHg with placebo, 159/82 mmHg with lacidipine, 157/84 mmHg with hydrochlorothiazide and 152/82 mmHg with lacidipine plus hydrochlorothiazide. Systolic blood pressure was significantly reduced during all active treatment phases compared with placebo and that for the lacidipine plus hydrochlorothiazide phase was also significantly less than those for both of the other active treatment phases. There was no difference between sitting and standing blood pressure for any phase. Factorial analysis of the main effects of treatment indicated that the effects of lacidipine and hydrochlorothiazide on clinic blood pressure were additive and also that heart rate was higher when hydrochlorothiazide had been administered. Ambulatory blood pressure monitoring confirmed the pattern of the responses of blood pressure and showed that administration of hydrochlorothiazide had a significantly greater effect on systolic blood pressure and a longer duration of action than did administration of lacidipine. There was no difference in the frequency of adverse effects among any of the phases.

CONCLUSIONS

In treating elderly systolic hypertensives the diuretic hydrochlorothiazide is a more effective antihypertensive agent with a longer duration of action than is the calcium channel antagonist lacidipine. In combination the effects of these two drugs on blood pressure are additive.

Management of isolated systolic hypertension

Isolated systolic hypertension (ISH) [systolic blood pressure (SBP) > or = l60mm Hg with diastolic blood pressure (DBP) <90mm Hg] is the commonest form of hypertension in the elderly, and accounts for about 60% of all hypertensive conditions in the population aged over 65 years. It is associated with a significantly increased risk of cardiovascular and cerebrovascular morbidity and mortality. The landmark Systolic Hypertension in the Elderly Program (SHEP) study, published in 1991, has shown that lowering the SBP in elderly patients with ISH results in a significant reduction in cardiovascular events. These results have had a major impact on clinical practice in hypertension. On theoretical grounds, considering the pathophysiological mechanisms of ISH in the elderly, any drug which lowers total peripheral resistance and/or arterial stiffness should reduce SBP effectively in these patients. This effect has been observed in outcome studies and short term clinical trials using a variety of drugs from the 4 major antihypertensive classes: diuretics, beta(1)-blockers, calcium channel antagonists and ACE inhibitors. Other drugs, including alpha antagonists, may also be effective. In general, there is compelling evidence to support active treatment of any individual with an SBP > or = 160mm Hg. As in essential hypertension, the maximum benefit is gained by aggressive treatment of those individuals at highest risk because of coexisting cardiovascular risk factors. In these people, an SBP of 140 to 159mm Hg should be considered to be an indication for active management. Initial management should be by manipulation of lifestyle factors such as bodyweight, salt and alcohol intake and aerobic exercise. Drug therapy, generally well tolerated in low doses, should be considered if SBP remains > or = 160mm Hg, or > or = 140mm Hg in the presence of multiple risk factors. The choice of initial drug therapy should be influenced by the particular clinical situation. If there are no coexisting contraindications or co-indications for particular drugs, it is reasonable to begin treatment with a low dose of a thiazide-like diuretic, as used in the SHEP study. However, in short term treatment trials calcium channel antagonists and ACE inhibitors have been shown to lower SBP effectively and can be used in the appropriate clinical context. Beta-blockers appear to be less effective as monotherapy in ISH. Combination therapy is frequently required and can be effective and well tolerated if carefully chosen.

ACE inhibitors. Differential use in elderly patients with hypertension

High blood pressure (BP) in the elderly must not be ignored as a normal consequence of aging. The criteria for the diagnosis of hypertension and the necessity to treat it are the same in elderly and younger patients. The aim of treatment of elderly hypertensive patients is to decrease BP safely and to reduce risk factors associated with cerebrovascular, cardiovascular and renal morbidity and mortality. The treatment of elderly hypertensive patients should be adjusted according to the needs of the individual, based upon age, race, severity of hypertension, co-existing medical problems, other cardiovascular risk factors, target-organ damage, risk-benefit considerations and costs. In addition to the elevated BP, other cardiovascular risk factors include smoking, glucose intolerance, hyperinsulinaemia, dyslipidaemia, hypercreatininaemia, peripheral vascular disease, left ventricular hypertrophy, and microalbuminuria (or albuminuria). Thus, the choice of initial antihypertensive therapy in elderly hypertensive patients should be based not only on the expected response, but also on the effects of therapy on lipid, potassium, glucose and uric acid levels, and left ventricular anatomy and function. Co-existing medical conditions (such as asthma, diabetes mellitus, heart failure, renal failure, gout, coronary artery disease, hyperlipidaemia and peripheral vascular disease) are major determinants for the selection of antihypertensive medications. With previous therapies (diuretics, beta-blockers, etc.), good BP control in the elderly was associated with clear and statistically significant reductions in stroke-related morbidity and mortality, but the overall effects on cardiovascular and renal complications of hypertension was either more variable or less obvious. Angiotensin converting enzyme (ACE) inhibitors are not only efficacious antihypertensive agents in the elderly, but also appear promising in counteracting some of the cardiovascular and renal consequences of hypertension. They are well tolerated and have a relatively low incidence of adverse effects. ACE inhibitors possess ancillary characteristics that are potentially beneficial for many elderly patients, including reduction of left ventricular mass, lack of metabolic and lipid disturbances, no adverse CNS effects, no risk of induction of heart failure, and a low risk of orthostatic hypotension. Since ACE inhibitors may improve perfusion to the heart, kidney and brain, they are well worth considering for the treatment of elderly patients with hypertensive target organ damage, especially in patients with heart failure, and diabetic patients with early nephropathy.

Calcium antagonists. Drug interactions of clinical significance

The interaction of calcium antagonists, including the dihydropyridine calcium antagonists (e.g. nifedipine), verapamil and diltiazem, with drugs from other classes has major clinical ramifications as the use of drug combinations increases in frequency. Combinations are used in the treatment of disorders ranging from hypertension to cardiac rhythm disturbances, angina pectoris and peripheral vasospastic disease. In this era of organ transplantation, drugs like cyclosporin are coming into potential conflict with an ever-growing list of drugs. Drug combinations used as part of long term therapies are also making their appearance in toxic drug reactions, including antituberculous and anticonvulsant agents. Bronchodilators and H2-blockers also fall into this category of potential culprits of combined drug toxicity, and the interactions of calcium antagonists with beta-blockers and antiarrhythmic agents are also becoming a matter of concern.