Angiotensin II-receptor blocker dosages: how high should we go?

Renin-angiotensin system blocking drugs

The two major classes of drugs that target the RAS are the angiotensin-converting enzyme (ACE) inhibitors and the selective AT1 receptor blockers (ARBs). Although both of these drug classes target angiotensin II, the differences in their mechanisms of action have implications for their effects on other pathways and receptors that may have therapeutic implications. Both ACEIs and ARBs are effective antihypertensive agents that have been shown to reduce the risk of cardiovascular and renal events. Direct inhibition of renin -the most proximal aspect of the RAS -became clinically feasible from 2007 with the introduction of aliskiren. This latter drug has been shown to be efficacious for the management of hypertension. Combined therapy of direct renin-inhibitors with ACEIs or ARBs has been tested in some clinical situations as congestive HF and proteinuria with diverse results. This article tries to offer an updated review of current knowledge on the use of RAS blocking drugs in clinical settings.

Treatment of proteinuria with lercanidipine associated with reninangiotensin axis-blocking drugs

Aim. Most calcium antagonists do not seem to reduce microalbuminuria or proteinuria. We have tried to assess the antiproteinuric effect of a calcium channel blocker, lercanidipine, in patients previously treated with ACE inhibitors or angiotensin receptor blockers.Design and methods. The study included 68 proteinuric (>500 mg/day) patients (age 63,1±12,9 years, 69,1 % males and 30,9 % females). All patients were receiving ACE inhibitors (51,4 %) or angiotensin II receptor blockers (48,6 %) therapy but had higher blood pressure (BP) than recommended for proteinuric patients (<130/80 mm Hg). Patients were clinically evaluated one, three, and six months after starting treatment with lercanidipine (20 mg/day). Samples for urine and blood examination were taken during the examination. When needed, a third drug was added to treatment. Creatinine clearance was measured using 24 h urine collection.Results. BP significantly decreased from 152±15/86±11 mm Hg to 135±12/77±10 mm Hg at six months of follow-up (p<0,001). After six months of treatment, the percentage of normalized patients (BP <130/80 mm Hg) was 42,5 %, and the proportion of patients whose BP was below 140/90 mm Hg was 58,8 %. Plasmatic creatinine did not change nor did creatinine clearance. Plasmatic cholesterol also decreased from 210±48 to 192±34 mg/dL (p<0,001), as did plasma triglycerides (from 151±77 to 134±72 mg/dL,p=0,022). Basal proteinuria was 1,63±1,34 g/day; it was significantly (p<0,001) reduced by 23 % at the first month, 37 % at three months, and 33 % at the last visit.

Conclusion. Lercanidipine at 20 mg dose, associated with renin-angiotensin axis-blocking drugs, showed a high antihypertensive and antiproteinuric effect. This antiproteinuric effect seems to be dose-dependent as compared with previous reports and proportionally higher than blood pressure reduction.

Persistent microalbuminuria after treatment with renin-angiotensin axis blockers: causes and results of treatment intensification

AIMS

The first phase of this study aimed to determine the causes of persistent microalbuminuria after treatment with renin-angiotensin axis (RAA) blocking drugs. In a second phase we tried to determine if strict control of blood pressure and intensive RAA blockade could induce remission or reduction of microalbuminuria in clinical (primary care) practice.

PATIENTS AND METHODS

The study included both diabetic patients and non-diabetic hypertensive patients treated with RAA drugs in the presence of microalbuminuria. 211 patients were recruited (mean age 66.6±11.3 years, 111 men, 117 were diabetic). In the first phase treatment was optimized at standard doses. In the second phase treatment was increased during a three months period to reach a blood pressure (BP) < 130/80 mmHg by adding other antihypertensive treatment and to obtain maximal RAA blockade using long-acting drugs, increased dosage, or adding further medication at night.

RESULTS

Initial mean BP was 141±16/81±11 mmHg. BP control was unsatisfactory (control of systolic blood pressure [SBP] 19.3%; diastolic blood pressure [DBP] 37.6%). Dosage of RAA blocking drugs was inadequate in 21% of patients. Only 27.4% of patients were taking antihypertensive drugs at night. 30.1% of patients took once daily short acting drugs. During the studymean SBP was reduced to 137±13 mmHg (p < .001) and DBP decreased to 79±10 mmHg (p < .001). Control of SBP improved to 24.5% and DBP control went to 44.4%. Mean microalbuminuria decreased from 64.4±47.0 mg/day to 50.1±53.0 mg/day (p < .001) and the prevalence of microalbuminuria was reduced to 59.1%.

CONCLUSIONS

Persistent microalbuminuria was associated with poor blood pressure control and inadequate drug dosage. Low frequency of administration of drugs at night and inappropriate once-daily pills intake were frequent. Strict control of blood pressure and intensive RAA blockade significantly reduced the prevalence of microalbuminuria.

Treatment of proteinuria with lercanidipine associated with renin-angiotensin axis-blocking drugs

OBJECTIVE

Most calcium antagonists do not seem to reduce microalbuminuria or proteinuria. We have tried to assess the antiproteinuric effect of a calcium channel blocker, lercanidipine, in patients previously treated with ACE inhibitors or angiotensin receptor blockers.

DESIGN AND METHODS

The study included 68 proteinuric (> 500 mg/day) patients (age 63.1 +/- 12.9 years, 69.1% males and 30.9 females). All patients were receiving ACE inhibitors (51.4%) or angiotensin II receptor blockers (48.6%) therapy but had higher blood pressure than recommended for proteinuric patients (<130/80 mmHg). Patients were clinically evaluated one, three, and six months after starting treatment with lercanidipine (20 mg/day). Samples for urine and blood examination were taken during the examination. When needed, a third drug was added to treatment. Creatinine clearance was measured using 24 h urine collection.

RESULTS

BP significantly decreases from 152 +/- 15/86 +/- 11 mmHg to 135 +/- 12/77 +/- 10 mmHg at six months of follow-up (p < 0.001). After six months of treatment, the percentage of normalized patients (BP < 130/80 mmHg) was 42.5%, and the proportion of patients whose BP was below 140/90 mmHg was 58.8%. Plasmatic creatinine did not change nor did creatinine clearance. Plasmatic cholesterol also decreased from 210 +/- 48 to 192 +/- 34 mg/dL (p < 0.001), as did plasma triglycerides (from 151 +/- 77 to 134 +/- 72 mg/dL, p = 0.022). Basal proteinuria was 1.63 +/- 1.34 g/day; it was significantly (p < 0.001) reduced by 23% at the first month, 37% at three months, and 33% at the last visit.

CONCLUSIONS

Lercanidipine at 20 mg dose, associated to renin-angiotensin axis-blocking drugs, showed a high antihypertensive and antiproteinuric effect. This antiproteinuric effect seems to be dose-dependent as compared with previous reports and proportionally higher than blood pressure reduction.

Comparison of valsartan/hydrochlorothiazide combination therapy at doses up to 320/25 mg versus monotherapy: a double-blind, placebo-controlled study followed by long-term combination therapy in hypertensive adults

BACKGROUND

One third of patients treated for hypertension attain adequate blood pressure (BP) control, and multidrug regimens are often required. Given the lifelong nature of hypertension, there is a need to evaluate the long-term efficacy and tolerability of higher doses of combination anti-hypertensive therapies.

OBJECTIVE

This study investigated the efficacy and tolerability of valsartan (VAL) or hydrochlorothiazide (HCTZ)-monotherapy and higher-dose combinations in patients with essential hypertension.

METHODS

The first part of this study was an 8-week, multicenter, randomized, double-blind, placebo controlled, parallel-group trial. Patients with essential hypertension (mean sitting diastolic BP [MSDBP], > or =95 mm Hg and <110 mm Hg) were randomized to 1 of 8 treatment groups: VAL 160 or 320 mg; HCTZ 12.5 or 25 mg; VAL/HCTZ 160/12.5, 320/12.5, or 320/25 mg; or placebo. Mean changes in MSDBP and mean sitting systolic BP (MSSBP) were analyzed at the 8-week core study end point. VAL/HCTZ 320/12.5 and 320/25 mg were further investigated in a 54-week, open-label extension. Response was defined as MSDBP <90 mm Hg or a > or =10 mm Hg decrease compared to baseline. Control was defined as MSDBP <90 mm Hg compared with baseline. Tolerability was assessed by monitoring adverse events at randomization and all subsequent study visits and regular evaluation of hematology and blood chemistry.

RESULTS

A total of 1346 patients were randomized into the 8-week core study (734 men, 612 women; 924 white, 291 black, 23 Asian, 108 other; mean age, 52.7 years; mean weight, 92.6 kg). All active treatments were associated with significantly reduced MSSBP and MSDBP during the core 8-week study, with each monotherapy significantly contributing to the overall effect of combination therapy (VAL and HCTZ, P < 0.001). Each combination was associated with significantly greater reductions in MSSBP and MSDBP compared with the monotherapies and placebo (all, P < 0.001). The mean reduction in MSSBP/MSDBP with VAL/HCTZ 320/25 mg was 24.7/16.6 mm Hg, compared with 5.9/7.0 mm Hg with placebo. The reduction in MSSBP was significantly greater with VAL/HCTZ 320/25 mg compared with VAL/HCTZ 160/12.5 mg (P < 0.002). Rates of response and BP control were significantly higher in the groups that received combination treatment compared with those that received monotherapy. The incidence of hypokalemia was lower with VAL/HCTZ combinations (1.8%-6.1%) than with HCTZ monotherapies (7.1%-13.3%). The majority of adverse events in the core study were of mild to moderate severity. The efficacy and tolerability of VAL/HCTZ combinations were maintained during the extension (797 patients).

CONCLUSIONS

In this study population, combination therapies with VAL/HCTZ were associated with significantly greater BP reductions compared with either monotherapy, were well tolerated, and were associated with less hypokalemia than HCTZ alone.