Safety and efficacy of the oral direct renin inhibitor aliskiren in elderly patients with hypertension

OBJECTIVES: To evaluate the efficacy, safety and tolerability of aliskiren in elderly patients (> or =65 years old) with essential hypertension. METHODS: In this double-blind, multicenter study, 355 elderly patients with hypertension [office mean sitting systolic blood pressure (msSBP) > or =145-<180 mmHg and mean 24-h ambulatory systolic BP (ASBP) > or =135 mmHg] were randomized to once-daily treatment for 8 weeks with aliskiren 75 mg (n = 91), 150 mg (n = 84), 300 mg (n = 94) or the comparator lisinopril 10 mg (n = 86). The primary efficacy variable was change in mean 24-h ASBP. RESULTS: At endpoint, aliskiren 75 mg, 150 mg, 300 mg and lisinopril 10 mg lowered mean 24-h ASBP (least-squares mean+/-SEM) by 8.4+/-0.8, 7.1+/-0.8, 8.7+/-0.8 and 10.2+/-0.9 mmHg, and mean 24-h ambulatory diastolic BP by 4.5+/-0.5, 3.6+/-0.5, 3.9+/-0.5 and 6.3+/-0.5 mmHg, respectively, with no significant difference between aliskiren doses. The trough-to-peak ratio for ASBP reduction with aliskiren 75 mg, 150 mg, 300 mg and lisinopril 10 mg was 0.77, 0.64, 0.79 and 0.87, respectively. All treatments lowered office msSBP and mean sitting diastolic BP (msDBP) compared with baseline. A significantly greater proportion of patients receiving aliskiren 300 mg achieved BP control (msSBP/msDBP <140/90 mmHg) compared with those receiving aliskiren 75 mg (36.2% vs 24.2%, p = 0.033). There was no evidence of dose-related increases in the rate of adverse events with aliskiren treatment. CONCLUSIONS: Aliskiren, a novel direct renin inhibitor, provides effective 24-h BP lowering with no evidence of dose-related increases in the incidence of adverse events in elderly patients with hypertension.     

Antihypertensive efficacy,safety, and tolerability of the oral direct renin inhibitor aliskiren in patients with hypertension: a pooled analysis

The antihypertensive efficacy and safety of the direct renin inhibitor aliskiren were assessed in a pooled analysis of data from seven randomized, multicenter studies. Data were available for 7,045 patients (mean age 52.5 to 59.8 years, 50.2 to 72.5% men) with mild-to-moderate hypertension (mean sitting diastolic blood pressure [msDBP] 95 to 109 mm Hg) over treatment durations of 6 to 8 weeks. In placebo-controlled trials, aliskiren reduced mean sitting systolic blood pressure/msDBP from baseline by 8.6 to 12.1/7.2 to 10.3 mm Hg (75 mg), 8.7 to 13.0/7.8 to 10.3 mm Hg (150 mg), 14.1 to 15.8/10.3 to 12.3 mm Hg (300 mg), and 15.7 to 15.8/11.5 to 12.5 mm Hg (600 mg), compared with 2.9 to 10.0/3.3 to 8.6 mm Hg for placebo. Aliskiren demonstrated comparable efficacy in men and women, in patients aged <65 years or ≥65 years, and lowered blood pressure (BP) effectively in all racial subgroups. Combination of aliskiren 150 mg or 300 mg with ramipril, amlodipine, or hydrochlorothiazide provided significant additional BP reductions compared with the respective monotherapies. The overall incidence of adverse events with aliskiren monotherapy was similar to placebo (39.8% vs. 40.2%, respectively). The incidence of diarrhea with aliskiren was higher than placebo due to a significantly higher rate with aliskiren 600 mg (P < .0001 vs. placebo). In conclusion, aliskiren 150 mg or 300 mg provides highly effective and consistent BP lowering with placebo-like tolerability in patients with mild-to-moderate hypertension.     

Safety and tolerability of the direct renin inhibitor aliskiren: a pooled analysis of clinical experience in more than 12,000 patients with hypertension

While the safety of renin-angiotensin system (RAS)-blocking drugs such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers is well known, less is known about the new direct renin inhibitor aliskiren. The authors pooled data from 12 randomized controlled trials of aliskiren in patients with hypertension and analyzed the incidence and types of adverse events (AEs) and laboratory abnormalities. Studies were characterized as short-term (≤2 months) placebo-controlled or long-term (>2 months) active-controlled. Relative risks for AEs of particular interest for RAS blockers were calculated. In short-term studies, AEs occurred in similar proportions of aliskiren 150 mg and 300 mg (33.6% and 31.6%, respectively) and placebo treatment groups (36.8%). In long-term studies, a lower proportion of patients treated with aliskiren 150 mg and 300 mg had AEs (33.7% and 43.2%, respectively) than those treated with ACE inhibitors (60.1%), angiotensin receptor blockers (53.9%), and thiazide diuretics (48.9%). Events of special interest, including angioedema, hyperkalemia, and diarrhea occurred in similar proportions of patients taking aliskiren, placebo, and comparator agents. In studies of up to 36 weeks, patients treated with aliskiren were significantly less likely to develop cough than those treated with ACE inhibitors. At the registered doses of 150 mg and 300 mg daily, aliskiren has safety and tolerability profiles similar to placebo, other RAS blockers, and diuretics. Cough rates are lower with aliskiren compared with ACE inhibitors.     

Effect of add-on direct renin inhibitor aliskiren in patients with non-diabetes related chronic kidney disease

ABSTRACT: BACKGROUND: The renin-angiotensin-aldosterone system (RAAS) plays an important role in the progression of chronic kidney disease (CKD). Although dual RAAS inhibition results in worse renal outcomes than monotherapy in high risk type 2 diabetes patients, the effect of dual RAAS inhibition in patients with non-DM CKD is unclear. The aim of this study was to evaluate the potential renoprotective effect of add-on direct renin inhibitor in non-DM CKD patients. METHODS: We retrospectively enrolled 189 non-DM CKD patients who had been taking angiotensin II receptor blockers (ARBs) for more than six months. Patients were divided into an add-on aliskiren group and an ARB monotherapy group. The primary outcomes were a decline in glomerular filtration rate (GFR) and a reduction in urinary protein-to-creatinine ratio at six months. RESULTS: The baseline characteristics of the two groups were similar. Aliskiren 150 mg daily reduced the urinary protein-to-creatinine ratio by 26% (95% confidence interval, 15 to 37%; p < 0.001). The decline in GFR was smaller in the add-on aliskiren group ([MINUS SIGN]2.1 vs. -4.0 ml/min, p = 0.038). Add-on aliskiren had a neutral effect on serum potassium in the non-DM CKD patients. In subgroup analysis, the proteinuria-reducing effect of aliskiren was more prominent in patients with a GFR less than 60 ml/min, and in patients with a urinary protein-to-creatinine ratio greater than 1.8. The effect of aliskiren in retarding the decline in GFR was more prominent in patients with hypertensive nephropathy than in those with glomerulonephritis. CONCLUSION: Add-on direct renin inhibitor aliskiren (150 mg daily) safely reduced proteinuria and attenuated the decline in GFR in the non-DM CKD patients who were receiving ARBs.     

Efficacy and safety of aliskiren, a direct renin inhibitor, compared with ramipril in Asian patients with mild to moderate hypertension

This 8-week, randomized, double-blind, parallel-group study compared the efficacy and safety of aliskiren with ramipril in Asian patients with mild to moderate hypertension. Following a 2- to 3-week placebo run-in period, patients with mean sitting diastolic blood pressure (msDBP) ≥95 and <110 mm Hg were randomized to receive once daily dose of either aliskiren 75, 150, 300 mg or ramipril 5 mg for 8 weeks. Efficacy variables were the changes in msDBP and mean sitting systolic BP (msSBP) and BP control rates (<140/90 mm Hg). Safety was assessed by recording adverse events (AEs) and serious AEs (SAEs). Of 1316 randomized patients, 1160 (88.1%) completed the study. At the study endpoint, patients on aliskiren had greater mean BP reductions (14.39/11.63 mm Hg for 300 mg; 12.16/10.04 mm Hg for 150 mg; 12.24/10.66 mm Hg for 75 mg) than those on 5 mg ramipril (11.46/9.19 mm Hg). All aliskiren doses were statistically non-inferior (P<0.0001) to ramipril in reducing msDBP. The reduction in BP for aliskiren 300 mg was statistically superior vs. ramipril (P<0.002). Blood pressure control rates were higher for aliskiren (300 mg, 52.29%; 150 mg, 48.11%; 75 mg, 45.68%) than for ramipril (5 mg, 43.7%); the difference for aliskiren 300 mg vs. ramipril 5 mg was statistically significant (P<0.05). Aliskiren was well tolerated with a fourfold lower incidence of cough (0.6-1.2%) compared with ramipril (5.2%). SAEs were rare in this study (0.5%). Aliskiren produced greater BP reductions with a lower incidence of cough than ramipril in Asian patients with mild to moderate hypertension.     

Blood pressure lowering in essential hypertension with an oral renin inhibitor, aliskiren

Inhibition of the first and rate-limiting step of the renin-angiotensin system has long been an elusive therapeutic goal. Aliskiren, the first known representative of a new class of completely nonpeptide, orally active, renin inhibitors, has been shown to inhibit the production of angiotensin I and II in healthy volunteers and to reduce blood pressure (BP) in sodium-depleted marmosets. The aim of this randomized, double-blind, active comparator trial study was to assess the BP-lowering efficacy and safety of aliskiren. Two hundred twenty-six patients, 21 to 70 years of age, with mild to moderate hypertension, were randomly assigned to receive 37.5 mg, 75 mg, 150 mg, or 300 mg aliskiren or 100 mg losartan daily for 4 weeks. Dose-dependent reductions in daytime ambulatory systolic pressure (mean change, mm Hg [SD of change]; -0.4 [11.7], -5.3 [11.3], -8.0 [11.0], and -11.0 [11.0], P=0.0002) and in plasma renin activity (median change % [interquartile range]; -55 [-64, -11], -60 [-82, -46], -77 [-86, -72], and -83 [-92, -71], P=0.0008) were observed with 37.5, 75, 150, and 300 mg aliskiren. The change in daytime systolic pressure with 100 mg losartan (-10.9 [13.8]) was not significantly different from the changes seen with 75, 150, and 300 mg aliskiren. Aliskiren was well tolerated at all doses studied. This study demonstrates that aliskiren, through inhibition of renin, is an effective and safe orally active BP-lowering agent. Whether renin inhibition results in protection from heart attack, stroke, and nephropathy, similar to angiotensin-converting enzyme inhibition and angiotensin receptor blockade, needs to be researched.     

Antihypertensive efficacy of the oral direct renin inhibitor aliskiren as add-on therapy in patients not responding to amlodipine monotherapy

This study investigated the addition of the direct renin inhibitor aliskiren to amlodipine in patients with mild to moderate hypertension that was inadequately controlled with amlodipine alone. Following once-daily treatment with amlodipine 5 mg for 4 weeks, patients whose hypertension responded inadequately to therapy (mean sitting diastolic blood pressure [DBP] 90-109 mm Hg) (n=545) were randomized to 6 weeks of double-blind treatment with amlodipine 5 mg plus aliskiren 150 mg, amlodipine 5 mg, or amlodipine 10 mg. At the study's end, mean systolic blood pressure and DBP reductions with the combination of aliskiren 150 mg and amlodipine 5 mg (11.0/8.5 mm Hg) were significantly greater (P<.0001) than with amlodipine 5 mg (5.0/4.8 mm Hg)--the comparator group--but similar to amlodipine 10 mg (9.6/8.0 mm Hg). All treatments were well tolerated. Edema occurred more frequently with amlodipine 10 mg (11.2%) than with combination therapy (2.1%) or amlodipine 5 mg (3.4%). In conclusion, aliskiren 150 mg plus amlodipine 5 mg shows similar but not better blood pressure-lowering efficacy when compared with amlodipine 10 mg in patients not completely responsive to amlodipine 5 mg; less edema was noted with combination therapy.     

Electromechanical effects of the direct renin inhibitor (aliskiren) on the pulmonary vein and atrium

Activation of the atrial renin–angiotensin system plays an important role in the pathophysiology of atrial fibrillation (AF). The pulmonary vein (PV) and left atrium (LA) are important trigger and substrate for the genesis of AF. We investigate the effects of a direct renin inhibitor, aliskiren, on the PV and LA arrhythmogenic activity and the underlying electromechanical mechanisms. Conventional microelectrodes were used to record action potentials and contractility in isolated rabbit PVs and LA tissues before and after the administration of aliskiren (0.1, 1, 3 and 10 μM). By the whole-cell patch clamp and indo-1 fluorimetric ratio techniques, ionic currents and intracellular calcium transient were studied in isolated single PV and LA cardiomyocyte before and after the administration of aliskiren (3 μM). Aliskiren (0.1, 1, 3 and 10 μM) reduced PV firing rate in a concentration-dependent manner (6, 10, 14 and 17%) and decreased PV diastolic tension, which could be attenuated in the presence of 100 μM L-N^G-Nitroarginine Methyl Ester (L-NAME). Aliskiren induced PV automatic rhythm exit block causing slow and irregular PV activity with variable pauses. Aliskiren increased PV and LA contractility, which could be abolished by pre-treating with 0.1 μM ryanodine. Aliskiren (3 μM) decreased L-type calcium currents, but increased reverse-mode of Na ⁺ /Ca²⁺ exchanger currents, intracellular calcium transients, and sarcoplasmic reticulum calcium content in PV and LA cardiomyocytes. Pretreatment with renin, losartan or angiotensin II did not alter the effect of aliskiren on sarcolemmal calcium flux. In conclusion, aliskiren reduces PV arrhythmogenic activity with a direct vasodilatory property and has a positive inotropic effect on cardiomyocytes. These findings may reveal the anti-arrhythmic and anti-heart failure potentials of aliskiren.     

Aliskiren: The first direct renin inhibitor for hypertension

Aliskiren is the first member of a novel class of antihypertensive agents, the renin inhibitors, that has been approved by the US Food and Drug Administration for the treatment of hypertension. This review discusses its potential differences compared with existing renin-angiotensin-aldosterone system blockers, focusing also on the inactive precursor of renin, prorenin, and the recently discovered (pro)renin receptor. The review summarizes the findings from all clinical trials with aliskiren published so far, and provides an overview of the safety and tolerability of the new drug.     

Aliskiren, a novel oral renin inhibitor, provides dose-dependent efficacy and placebo-like tolerability in Japanese patients with hypertension.

Aliskiren is a novel orally active renin inhibitor for the treatment of hypertension. This study evaluated the antihypertensive efficacy, safety and tolerability of aliskiren in Japanese patients with hypertension. Forty hundred and fifty-five Japanese men and women with a mean sitting diastolic blood pressure of 95-110 mmHg were randomized to receive once-daily double-blind treatment for 8 weeks with aliskiren 75, 150 or 300 mg or placebo. Aliskiren produced significant, dose-dependent reductions in mean sitting diastolic blood pressure (p<0.0005 vs. placebo for each dose) and mean sitting systolic blood pressure (p<0.001 vs. placebo for each dose). The placebo-corrected reductions in mean sitting systolic/diastolic blood pressure were 5.7/4.0, 5.9/4.5 and 11.2/7.5 mmHg in the aliskiren 75, 150 and 300 mg groups, respectively. After 8 weeks' treatment, 27.8%, 47.8%, 48.2% and 63.7% of patients in the placebo and aliskiren 75, 150 and 300 mg groups, respectively, achieved a successful treatment response (diastolic blood pressure <90 mmHg and/or reduced by > or =10 mmHg from baseline; p<0.005 vs. placebo for each dose). Aliskiren treatment was well tolerated, with the incidence of adverse events reported in the active treatment groups (53-55%) being similar to that in the placebo group (50%). This study, which is the first to assess the antihypertensive efficacy and safety of aliskiren in Japanese patients with hypertension, demonstrates that the once-daily oral renin inhibitor aliskiren provides significant, dose-dependent reductions in blood pressure with placebo-like tolerability.     

Comparative efficacy and safety of aliskiren, an oral direct renin inhibitor, and ramipril in hypertension: a 6-month, randomized, double-blind trial

OBJECTIVES: This double-blind study compared long-term efficacy, safety and tolerability of the oral direct renin inhibitor aliskiren and the angiotensin-converting enzyme inhibitor ramipril alone and combined with hydrochlorothiazide in patients with hypertension. METHODS: After a 2-4-week placebo run-in, 842 patients [mean sitting diastolic blood pressure (msDBP) 95-109 mmHg] were randomized to aliskiren 150 mg (n = 420) or ramipril 5 mg (n = 422). Dose titration (to aliskiren 300 mg/ramipril 10 mg) and subsequent hydrochlorothiazide addition (12.5 mg, titrated to 25 mg if required) were permitted at weeks 6, 12, 18 and 21 for inadequate blood pressure control. Patients completing the 26-week active-controlled treatment period were re-randomized to their existing regimen or placebo for a 4-week double-blind withdrawal phase. RESULTS: Six hundred and eighty-seven patients (81.6%) completed the active treatment period. At week 26, aliskiren-based therapy produced greater mean reductions in mean sitting systolic blood pressure (17.9 versus 15.2 mmHg, P = 0.0036) and msDBP (13.2 versus 12.0 mmHg, P = 0.025), and higher rates of systolic blood pressure control (< 140 mmHg; 72.5 versus 64.1%, P = 0.0075) compared with ramipril-based therapy. During withdrawal, blood pressure increased more rapidly after stopping ramipril than aliskiren-based therapy; median blood pressure reached 140/90 mmHg after 1 and 4 weeks, respectively. Blood pressure reductions were maintained with continued active treatment. Aliskiren therapy was well tolerated. Overall adverse event rates were similar with aliskiren (61.3%) and ramipril (60.4%); cough was more frequent with ramipril (9.5%) than aliskiren (4.1%). CONCLUSIONS: Aliskiren-based therapy was well tolerated and produced sustained blood pressure reductions in patients with hypertension over 6 months, greater than those with ramipril-based therapy.     

The renin inhibitor aliskiren upregulates pro-angiogenic cells and reduces atherogenesis in mice

Sca-1 and VEGFR-2 positive pro-angiogenic cells (PAC) predict outcome of patients with vascular disease. Activation of the renin–angiotensin–aldosterone system impairs PAC function. The effects of the direct renin inhibitor aliskiren on PAC numbers and function are not known. Treatment of C57Bl/6 mice and Apo E^−/− mice on high-cholesterol diet with aliskiren, 25 mg/kg/day s.c. for 3–6 weeks, reduced systolic and diastolic blood pressure by −11.5 and −13.7% compared to vehicle. Aliskiren increased Sca-1/VEGFR-2 positive PAC in the blood (159 ± 14%) and spleen-derived DiLDL/lectin positive PAC (180 ± 21%). Migratory capacity of PAC was increased to 165 ± 16%. In cultured human PAC, aliskiren dose-dependently increased the number of colony forming units to 152 ± 9% (1 μmol/l) and 187 ± 7% (10 μmol/l), which was prevented by the eNOS inhibitor LNMA. H₂O₂-induced apoptosis of cultured human PAC was reduced to 77 ± 23%. In Apo E^−/− mice, aliskiren reduced atherosclerotic plaque area in the aortic sinus by 58 ± 4%. Circulating Sca-1/VEGFR-2 positive PAC were upregulated to 180 ± 25% and migratory capacity of PAC was increased to 127 ± 7%. Aliskiren reduced vascular NADPH oxidase activity to 41.6 ± 6.7%. Despite similar blood pressure lowering, treatment with hydralazine (25 mg/kg/day) did not significantly influence atherogenesis or PAC. Treatment of C57Bl/6 mice with a lower dose of aliskiren (15 mg/kg/day) did not affect blood pressure but increased cultured DiLDL/lectin positive PAC to 229 ± 30% and their migratory capacity to 214 ± 24%. Aliskiren increased number and function of PAC in mice and prevented atherosclerotic lesion formation. The effects were observed independent of blood pressure lowering.     

Assessment of renin dependency of hypertension with a dipeptide renin inhibitor

To evaluate the participation of the renin-angiotensin system in sustaining hypertension, we administered the specific dipeptide renin inhibitor enalkiren (A-64662) to 18 patients with essential hypertension. Ascending intravenous bolus doses (0.03, 0.1, 0.3, and 1.0 mg/kg) of the inhibitor were each given at 45-minute intervals to patients maintained on an ad libitum sodium diet who were studied while in bed in the semirecumbent posture. Enalkiren produced marked decreases in plasma renin activity (PRA) that were still evident 8 hours after completion of dosing. Systolic and diastolic blood pressures were decreased in a dose-dependent fashion without an effect on heart rate. Repetition of this procedure after patients were subjected to sodium depletion by 1 week of thiazide treatment produced amplified decreases in blood pressure. Despite the short plasma half-life of the inhibitor, these blood pressure-lowering effects were sustained for 4-8 hours when compared with parallel placebo administration in the same patients. Both the baseline PRA and the inhibitor-induced changes in PRA correlated significantly with blood pressure changes during the unstimulated and the sodium-depleted studies. However, effects of the inhibitor on diastolic blood pressure in the latter study correlated most closely with actual increases in renin produced by diuretic pretreatment. Thus, this specific renin inhibitor has demonstrated the dependency of blood pressure on the renin-angiotensin system even during basal conditions in hypertensive patients. Moreover, renin response to sodium depletion appears to be an attribute that additionally characterizes individual hypertensive patients.     

Effects of the renin inhibitor MK-8141 (ACT-077825) in patients with hypertension

The renin inhibitor MK-8141 (ACT-077825) demonstrates substantial immunoreactive active renin (ir-AR) increase (sevenfold) without a persistent plasma renin activity (PRA) decrease. The present study assessed the antihypertensive efficacy of MK-8141 in hypertensive patients. In this double-blind, placebo- and active comparator-controlled study, 195 patients with hypertension (trough sitting diastolic blood pressure ≥92 to <105 mm Hg, trough sitting systolic blood pressure <170 mm Hg, and 24-hour mean diastolic blood pressure [DBP] ≥80 mm Hg) were randomized to one of four treatments (stratified by race, black versus others): MK-8141 250 mg, MK-8141 500 mg, enalapril 20 mg, or placebo. Blood pressure was measured at trough and as 24-hour ambulatory blood pressure monitoring. The primary end point was change from baseline in 24-hour mean ambulatory DBP measured after 4 weeks. At week 4, the change from baseline in 24-hour mean (95% CI) ambulatory DBP compared with placebo was ?1.6 mm Hg (?4.2, 1.1), ?1.1 mm Hg (?3.9, 1.6), and ?4.9 (?7.5, ?2.2) for MK-8141 250 mg, MK-8141 500 mg, and enalapril 20 mg, respectively. Only mean ambulatory DBP-lowering with enalapril 20 mg was statistically significant. Enalapril, but not MK-8141, also significantly lowered 24-hour mean ambulatory systolic blood pressure (SBP) compared with placebo (?6.7 mm Hg [?10.5, ?2.8]). Neither enalapril nor MK-8141 significantly lowered trough DBP and SBP compared with placebo. MK-8141 was generally well tolerated. In patients with hypertension, MK-8141 (ACT-077825) did not produce significant blood pressure–lowering efficacy despite a demonstrated effect of the drug on ir-AR, in the absence of durable PRA suppression.     

Renal plasma flow: glomerular filtration rate relationships in man during direct renin inhibition with aliskiren

We examined the relation between change in renal plasma flow (RPF) and change in glomerular filtration rate (GFR) in healthy humans on a low-salt diet during direct renin inhibition with aliskiren. We measured the renal hemodynamic response to acute dosing of 300 mg aliskiren by mouth to 19 healthy normotensive subjects (age, 33 ± 3 years; baseline RPF, 575 ± 23; GFR, 138 ± 14 mL/min/1.73 m²) on a low-sodium diet (10 mmol/day). GFR and RPF were measured by the clearance of inulin and para-aminohippurate. There was a marked increase in average RPF (169 ± 24 mL/min/1.73 m²) and a small rise in average GFR (1.4 ± 5 mL/min/1.73 m²) from baseline in response to aliskiren. There was a clear correlation between the change in RPF and the change in GFR between subjects (r = 0.65; P < .003). A substantial increase in RPF was accompanied by a rise in GFR. Dependence of GFR on RPF was identified in healthy humans after RPF rose significantly with aliskiren. The responsible mechanism likely involves intravascular oncotic pressure along the glomerular capillary resulting in greater surface area available for filtration.     

Evaluation of the antihypertensive effect of lisinopril compared with nifedipine in patients with mild to severe essential hypertension.

For several reasons, increasing numbers of patients with hypertension are treated with angiotensin-converting enzyme inhibitors and calcium channel blockers. In a twenty-four week, double-blind, randomized, parallel study, the antihypertensive effect of lisinopril (20 to 80 mg qd) and nifedipine (20 to 80 mg bid) were compared in 21 patients. Fourteen patients received lisinopril (mean dose 35 mg), and 7 patients received nifedipine (mean dose 54 mg). By the end of week 12, 8 patients had responded (supine diastolic pressure less than or equal to 90 mg) to lisinopril and 5 to nifedipine. At the end of the study supine systolic/diastolic blood pressure was reduced from 172/104 to 149/92 mmHg with lisinopril and from 171/102 to 158/94 mmHg with nifedipine. No significant difference between the two treatments was detected. Three patients were reported to have at least one clinical adverse experience during the active treatment period, 1 in the lisinopril group and 2 in the nifedipine group. No serious clinical adverse experiences were recorded. In conclusion, lisinopril and nifedipine are both effective in reducing blood pressure in patients with mild to severe hypertension. Lisinopril qd and nifedipine slow release bid produce similar decreases in blood pressure after twelve weeks of therapy and the safety profiles of the two drugs are similar.