Comparison of the antihypertensive effects of betaxolol and chlorthalidone as monotherapy and in combination.

In this multicenter, double-blind, parallel study, the antihypertensive effects of betaxolol (20 mg once daily) and/or chlorthalidone (25 mg once daily) were analyzed in 186 patients with essential hypertension. Following a 2- to 4-week placebo baseline period, patients were randomized to one of two treatment groups (betaxolol or chlorthalidone) and studied for 6 weeks while receiving single therapy and an additional 6 weeks with a combination of the two agents. Significant decreases from baseline supine diastolic blood pressure (SDBP) were observed in both groups at the end of the single-therapy phase (11 mm Hg in SDBP for betaxolol and 12 mm Hg in SDBP for chlorthalidone); a further significant decrease (7 mm Hg for betaxolol and 8 mm Hg for chlorthalidone in SDBP) was observed from the end of the single-therapy phase to the end of the combination-therapy phase. Changes in supine systolic blood pressure (SSBP) from baseline to the end of the single-therapy phase were 10 mm Hg for the betaxolol and 16 mm Hg for the chlorthalidone group. In all cases, within-group changes were statistically significant. From the end of single therapy to end of combination therapy there was an additional 14-mm Hg and 13-mm Hg reduction in SSBP in the betaxolol and chlorthalidone groups, respectively. Overall, 89% of the randomized patients completed the single-treatment phase (phase I), and 89% of those patients completed the combined therapy phase (phase II). There was no significant difference between treatment groups in the clinical response rate (SDBP at or below 90 mm Hg or a decrease from baseline of at least 10 mm Hg). A substantial percentage of patients completing phase I responded to either single agent (58% for betaxolol and 65% for chlorthalidone). Among patients completing phase II therapy, the combination of the two agents produced a greater response rate (83% for the betaxolol-first group and 85% for the chlorthalidone-first group). In conclusion, both agents were effective and well tolerated. The most frequent adverse events in the single-therapy phase were headache, arthralgia, and dizziness, while bradycardia, rhinitis, arthralgia, and dizziness were most frequent in the combination-therapy phase. The combination of betaxolol (20 mg) and chlorthalidone (25 mg) once daily produced an additive antihypertensive effect regardless of which drug was administered first.

Remission of mild to moderate hypertension after treatment with carteolol, a beta-adrenoceptor blocker with intrinsic sympathomimetic activity.

Previous studies have indicated that some hypertensive patients, following a period of effective treatment with certain antihypertensive drugs, may experience prolonged normotension after drug withdrawal. We have studied the ability of carteolol, a nonselective beta-adrenoceptor antagonist with intrinsic sympathomimetic activity, to produce such remissions of hypertension. Thirty-four patients whose diastolic blood pressure was controlled at 90 mm Hg or less with carteolol monotherapy (2.5 to 5.0 mg/d for an average of 328 days) were randomized to a nine-month, double-blind, placebo-controlled drug-withdrawal trial. Those patients randomized to continue carteolol therapy had initially responded to carteolol treatment with reduction in blood pressure from 151 +/- 4/99 +/- 2 to 132 +/- 4/80 +/- 2 mm Hg. Those randomized to treatment with placebo had initially responded with blood pressure reductions from 154 +/- 4/97 +/- 2 to 137 +/- 4/81 +/- 2 mm Hg. Changes in mean systolic and diastolic blood pressure (mm Hg +/- SEM) from baseline during carteolol therapy to the final visit at nine months were not different for patients receiving placebo (13 +/- 5/6 +/- 4 mm Hg, recumbent; 11 +/- 6/4 mm Hg, standing) or carteolol (11 +/- 5/7 +/- 3 mm Hg, recumbent; 12 +/- 6/7 +/- 3 mm Hg, standing). The final mean recumbent diastolic blood pressure (86.9 mm Hg) was the same in both groups. Prolonged normotension may follow a period of carteolol treatment, again suggesting the potential importance of periodic withdrawal of antihypertensive medication.

A multifactorial trial design to assess combination therapy in hypertension. Treatment with bisoprolol and hydrochlorothiazide.

BACKGROUND: The safety and effectiveness of different dosages and combinations of antihypertensive agents can be efficiently studied using a multifactorial trial design. In consultation with the Cardio-Renal Division of the Food and Drug Administration, we conducted a randomized, double-blind, placebo-controlled, 3 x 4 factorial trial of bisoprolol, a beta 1-selective adrenergic blocking agent, and hydrochlorothiazide. METHODS: A total of 512 patients with mild to moderate essential hypertension were randomized to once-daily treatment with bisoprolol (0, 2.5, 10, or 40 mg), hydrochlorothiazide (0, 6.25, or 25 mg), and all possible combinations. Diastolic and systolic blood pressures were monitored during this 12-week trial. RESULTS: The effects of bisoprolol and hydrochlorothiazide were additive with respect to reductions in diastolic and systolic blood pressures over the dosage ranges studied. The addition of hydrochlorothiazide (or bisoprolol) to therapy with bisoprolol (or hydrochlorothiazide) produced an incremental reduction in blood pressure. Dosages of hydrochlorothiazide as low as 6.25 mg/d contributed a significant antihypertensive effect. A hydrochlorothiazide dosage of 6.25 mg/d produced significantly less hypokalemia and less of an increase in uric acid levels than a dosage of 25 mg/d. The low-dose combination of bisoprolol, 2.5 mg/d, and hydrochlorothiazide, 6.25 mg/d, reduced diastolic blood pressure to lower than 90 mm Hg in 61% of patients and demonstrated a safety profile that compared favorably with that of placebo. CONCLUSIONS: The utility of factorial design trials to characterize dose-response relationships and to test the potential interactions between various antihypertensive agents has been demonstrated. The combination of low dosages of bisoprolol and hydrochlorothiazide may be a rational alternative to conventional stepped-care therapy for the initial treatment of patients with mild to moderate hypertension.

Nitrendipine in severe hypertension. Satellite symposium on calcium antagonists.

We report the results of a multicenter trial in which nitrendipine, alone or in combination with a diuretic, a beta-blocker, or both, was administered to 114 patients with severe hypertension (greater than or equal to 115 mm Hg). Nitrendipine was titrated in doses of 5 to 30 mg b.i.d. If blood pressure was not controlled with nitrendipine alone, hydrochlorothiazide or propranolol or both were added. After a mean of 29 days in the study, 96 (90%) of 107 patients reached the initial goal of therapy; in 44 (41%) given nitrendipine alone the mean decrease in supine blood pressure was 38/25 mm Hg. After a mean of 91 days, 69 (72%) of 96 patients achieved the final goal of therapy; in 24 (25%) patients given nitrendipine alone the mean supine blood pressure decrease from baseline was 49/33 mm Hg. Falls in blood pressure were comparable in the patients given drug combinations. Seventy-two of 114 patients given study drug(s) had adverse experiences; headache and edema were the most frequent complaints. Only four patients dropped out of the study because of adverse effects. Most abnormal laboratory values occurred when nitrendipine was given with hydrochlorothiazide or propranolol or both. Analysis of severely hypertensive patients followed up in our Virginia center revealed continued control of blood pressure after long-term follow-up (43 +/- 3 [SD] months). Average supine blood pressure was reduced from 180/121 +/- 21/5 to 140/90 +/- 16/9 (SD) mm Hg (p less than 0.001). It was concluded that the calcium antagonist nitrendipine, alone or in combination with a diuretic or beta-blocker or both, is effective in the treatment of severe hypertension.

Nonemergency use of slow infusions of diazoxide.

Slow infusions of diazoxide were administered to 10 hypertensive patients who had stable, nonaccelerated hypertension. The 10-min diazoxide infusion was associated with a 16% average reduction in arterial pressure, a 21% average increase in heart rate, a 16% average increase in cardiac output, and a 36% reduction in total peripheral resistance. These changes in hemodynamic parameters lasted for an average of 70 min. It was concluded that slow infusions of diazoxide produce a consistent and predictable antihypertensive effect in patients with stable, nonaccelerated hypertension. Slow infusions of diazoxide may have a limited use in nonemergency situations where an abrupt change in arterial pressure is to be avoided and a parenteral antihypertensive agent is needed.

The effect of amlodipine on ambulatory blood pressure in hypertensive patients.

Certain high-risk populations, such as diabetics and blacks, have sustained elevation in blood pressure and heart rate throughout the day and night, with blunting of the usual diurnal variability pattern. This may contribute to their higher incidence of left ventricular hypertrophy (blacks) and cardiovascular complications (diabetics). Hypertensives who maintain a diurnal pattern of blood pressure variation still exhibit higher daytime and nocturnal blood pressure levels than normotensives. Thus, to achieve maximum effectiveness in treating hypertension, 24-hour control of blood pressure is necessary. Antihypertensive agents should effectively reduce blood pressure consistently throughout a 24-hour period. The objective of this study was to assess the effects of amlodipine, 5 mg once daily, on blood pressure measured by 24-hour ambulatory monitoring in a randomized, double-blind, placebo-controlled single-site study. Patients with mild-to-moderate essential hypertension were randomized to receive amlodipine (n = 11) or placebo (n = 5) in a 2:1 ratio. A 4-week single-blind placebo run-in period was followed by a 4-week double-blind phase. Ambulatory monitoring of blood pressure was carried out for 24 hours at the end of each 4-week phase. Patients receiving amlodipine had significantly lower blood pressure compared with placebo 24 hours after the last dose (supine blood pressure -25.1/-10.1 mm Hg; standing blood pressure -21.2/-9.7 mm Hg) after 4 weeks of treatment. This effect was clearly demonstrated by the 24-hour postdose measurement and the mean blood pressure over the 24-hour interval as measured by ambulatory recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium intake and furosemide administration in hypertensive patients with renal insufficiency.

The effects of various levels of sodium intake and loop diuretic (furosemide) administration upon arterial pressure and renal function were studied in 11 patients with impaired renal function and essential hypertension. The patients were hospitalized in a metabolic ward and continued taking their usual antihypertensive medications. After a stabilization period, all patients followed the following regiments for 5 to 7 days: period I, 20 mEq sodium diet without diuretic administration; period II, 80 mEq sodium diet and furosemide, 80 mg daily; and period III, 200 mEq sodium diet and furosemide, 240 mg daily. Supine diastolic pressure was lower (P is less than 0.05) during period II than during period I and both supine and standing systolic and diastolic pressures were significantly lower in period III than in period I (P is less than 0.01). No significant differences in the renal clearance of inulin were noted between any of the study periods. In patients with essential hypertension and impaired renal function, consumption of a moderate or liberal sodium diet combined with administration of a loop diuretic agent (furosemide) appears to result in better control of arterial pressure without significant changes in renal function than does strict sodium restriction without diuretic administration.

Comparison of the antihypertensive effects of betaxolol to atenolol.

A randomized double-blind multicenter study compared a new oral beta 1-adrenergic antagonist, betaxolol 10 to 40 mg (n = 71), with atenolol 25 to 100 mg (n = 75). Each drug was administered once daily for 24 weeks in patients with mild to moderate hypertension. Blood pressure (BP) measurements were taken 24 hours after dosing. Each drug produced significant (p less than 0.01) reductions in mean supine diastolic BP. The mean decrease in supine diastolic BP with betaxolol was significantly greater at weeks 4, 6, 10 and 12 (p less than 0.05). Throughout the remainder of the trial (weeks 14 to 24), no significant differences in BP reduction were noted between treatment groups. Normotension (supine diastolic BP less than or equal to 90 mm Hg) was achieved in 72% of those given betaxolol compared with 52% of those given atenolol (p less than 0.05). The most common side effects noted were bradycardia, fatigue and headache. The incidence of these and of central nervous system side effects was similar between the betaxolol and atenolol groups. Both agents were well tolerated. At recommended doses, betaxolol once daily may be more effective than atenolol once daily in patients with mild to moderate hypertension.

Effectiveness of a new calcium antagonist in severe hypertension.

Nitrendipine is a new nifedipine-like calcium antagonist antihypertensive agent. In this study, nitrendipine 5-40 mg orally bid was administered for up to three months to 16 patients with severe essential hypertension (untreated supine diastolic blood pressure greater than or equal to 115 mm Hg). Hydrochlorothiazide or propranolol or both were also given to patients who did not achieve goal blood pressure with nitrendipine alone. Five patients achieved goal blood pressure (supine less than or equal to 90 mm Hg) with nitrendipine alone and six more after the addition of a second drug, and only four required triple-drug therapy. One patient was terminated from the study because of headaches, a common nitrendipine side effect. This study demonstrates that nitrendipine is an effective and well-tolerated agent in the treatment of severe hypertension.

First-line therapy option with low-dose bisoprolol fumarate and low-dose hydrochlorothiazide in patients with stage I and stage II systemic hypertension.

This 30-center, randomized, double-blind, placebo-controlled, parallel-group study was designed to (1) establish that 6.25 mg of hydrochlorothiazide (HCTZ) given once daily with 5 mg of bisoprolol fumarate can contribute to antihypertensive effectiveness in patients with stage I and stage II (mild to moderate) systemic hypertension; and (2) assess whether this formulation was more effective or possessed a safety advantage over standard monotherapy with bisoprolol or 25 mg of HCTZ. Results showed that HCTZ 6.25 mg contributed significantly to the antihypertensive effectiveness of bisoprolol 5 mg. Bisoprolol 5 mg/HCTZ 6.25 mg (B5/H6.25) produced significantly greater mean reductions from baseline in sitting systolic and diastolic blood pressure (-15.8 mm Hg/-12.6 mm Hg) than bisoprolol 5 mg alone (-10.0 mm Hg/-10.5 mm Hg) and HCTZ 25 mg alone (-10.2 mm Hg/-8.5 mm Hg). A 73% response rate was achieved with the low-dose formulation compared with 61% for the bisoprolol 5 mg (B5) group and 47% for the HCTZ 25 mg (H25) group. B5/H6.25 was found to be significantly more effective than B5 or H25 in all subgroups of patients, regardless of gender, race, age, or smoking history. Antihypertensive effects were maintained during the 24-hour dosing interval. The incremental effectiveness of B5/H6.25 was not accompanied by an increase in the frequency or severity of adverse experiences; the incidence of adverse experiences in the B5/H6.25 group was comparable to that in the placebo group. B5/H6.25 was shown to provide safety advantages over H25, as shown by less hypokalemia (< 1% with B5/H6.25 versus 6.5% with H25).(ABSTRACT TRUNCATED AT 250 WORDS)

Indapamide: clinical pharmacology, therapeutic efficacy in hypertension, and adverse effects.

Indapamide will soon be marketed in the United States as an oral antihypertensive agent and diuretic. Its molecular structure includes both a polar sulfamoyl chlorobenzamide moiety and a lipid-soluble methylindoline moiety. It differs chemically from the thiazides in that it does not possess the thiazide ring system and it contains only one sulfonamide group. Indapamide is rapidly and well absorbed after oral ingestion, and it has a long terminal half-life in whole blood which permits once daily administration. Indapamide is extensively metabolized by the liver with excretion of unchanged drug accounting for approximately 5% of the total dose. Although indapamide is thought to exert its antihypertensive effect by its diuretic action, several investigations employing laboratory animal preparations have documented a direct vascular action. It has been categorized as a calcium channel blocking agent and this may account for a portion of its antihypertensive effectiveness. In both the treatment of edema and as an antihypertensive agent, indapamide appears to be comparable to hydrochlorothiazide, chlorthalidone and furosemide and seems to have no clinically important advantage over these agents. Side effects associated with indapamide are minimal and appear to be comparable to those observed with other antihypertensive diuretics. Based on few published studies, indapamide appears to be a useful long acting antihypertensive and diuretic agent that is well tolerated and associated with minimal biochemical abnormalities or side effects.

Comparison of ramipril and enalapril in patients with essential hypertension.

STUDY OBJECTIVE: To compare the clinical safety and efficacy of ramipril, a new long-acting nonsulfhydryl inhibitor of angiotensin-converting enzyme (ACE), with enalapril. DESIGN: A randomized, double-blind trial. SETTING: Multicenter trial involving 4 large teaching hospitals and 12 community medical centers. PATIENTS: One hundred fifty-nine patients with mild to moderate essential hypertension were enrolled. Two patients were excluded from the efficacy analysis because they failed to return for follow-up. INTERVENTIONS: Patients were randomized to receive ramipril 2.5, 5, or 10 mg, or enalapril 5, 10, or 20 mg once/day for 3 or 4 weeks. MEASUREMENTS AND MAIN RESULTS: At baseline, supine diastolic blood pressures ranged from 98-116 mm Hg. Supine and standing systolic blood pressures were reduced by 11.8 and 10.2 mm Hg with ramipril 10 mg (p < or = 0.001) and 9.3 and 10.7 mm Hg with enalapril 20 mg (p < or = 0.001). At the end of the 4-week trial, patients in all six dosage groups had clinically and statistically significant reductions in supine diastolic blood pressure compared with baseline values. The agents did not differ significantly with respect to their blood pressure-lowering effects. Both lowered plasma ACE activity; after 4 weeks, changes from baseline were highly significant for all dosage groups (p < or = 0.001). CONCLUSION: Ramipril was as effective in reducing blood pressure and was as well tolerated as enalapril. A larger average decrease in plasma ACE activity was achieved with ramipril over all dosages (71%) compared with that for enalapril (48%), suggesting that ramipril has greater ACE inhibition in the circulation.

Transdermal administration of clonidine: a new approach to antihypertensive therapy.

This study assessed the antihypertensive efficacy and side effects of clonidine administered transdermally. Twenty-five patients with mild to moderate essential hypertension (seated diastolic blood pressure 95-120 mm Hg with diuretic therapy alone) controlled with oral diuretic plus oral clonidine were enrolled. Transdermal clonidine was substituted for oral clonidine and titrated until adequate blood pressure control (seated diastolic blood pressure less than 90 mm Hg) was attained. At the end of titration, seated morning blood pressure averaged 129/90 +/- 15/5 mm Hg (mean +/- standard deviation) compared to 136/96 +/- 13/7 mm Hg (p less than 0.01/0.001) during oral clonidine administration. Standing morning blood pressure was also lower during transdermal than oral therapy (131/94 +/- 16/5 vs 136/99 +/- 14/7, p less than 0.05/0.001). Afternoon blood pressures (at peak effect of oral dose) were virtually identical during oral and transdermal therapy in both seated and standing positions. Typical side effects of oral clonidine, including dry mouth, drowsiness, and sexual dysfunction, were reduced during transdermal therapy. There was less morning-to-afternoon variability of blood pressure control and plasma clonidine concentrations during transdermal than during oral therapy. One patient left the study because of drowsiness and two because of skin reactions to the transdermal skin patch. Mild transient local skin irritation occurred frequently. Transdermal clonidine plus a diuretic is an effective treatment for mild to moderate essential hypertension, improves compliance and reduces side effects of therapy.

Double-blind comparison of amlodipine and hydrochlorothiazide in patients with mild to moderate hypertension.

In the final analysis of this study at Week 26, 26% of the patients randomized to receive amlodipine attained blood pressure control with amlodipine alone compared with 33% of the patients allocated to hydrochlorothiazide (HCTZ). Neither amlodipine nor HCTZ produced clinically significant changes in pulse rate or in the electrocardiogram. Amlodipine treatment did not appear to produce clinically significant changes in blood lipids; HCTZ, however, produced an increase in total plasma cholesterol (delta 22.9 +/- 8.6 mg/dl). The incidence of side effects and the rate of patient withdrawal in the amlodipine and HCTZ groups were comparable. As expected, HCTZ therapy caused well-recognized biochemical alterations in cholesterol and potassium levels, whereas amlodipine was metabolically neutral.

The rational use of diuretics in the treatment of arterial hypertension.

The development of modern pharmacologic diuretic agents has revolutionized the therapy of arterial hypertension. The diuretics currently available are easily administered orally, are effective in the presence of alkalosis or acidosis, are non-toxic and have a low incidence of side effects which are readily circumvented or treated. Loop diuretics such as furosemide have the capacity to be effective in patients with diminished renal function or clinical situations that have a powerful stimulus to sodium retention. In clinical circumstances when renal potassium loss is to be prevented such as in patients receiving digitalis, the addition of a potassium-sparing diuretic to either a thiazide or furosemide will achieve the clinical goal of providing an effective diuresis while inhibiting potassium excretion. The mechanism of antihypertensive activity of the diuretic agents appears to be the reduction of extracellular fluid volumes and plasma volumes. Hence, the clinical dictum that to be effective as an antihypertensive agent, diuretics should be administered in diuretic doses. Besides being the cornerstone of initial antihypertensive therapy, diuretics also play an important role in antihypertensive therapy of patients with moderate to severe hypertension who are receiving potent antihypertensive drugs of the vasodilator or sympatholytic class of compounds. Indeed, one of the most important steps in the successful therapy of these patients receiving multiple drugs, is the re-assessment of the diuretic agent. The sodium retention and consequent fluid volume expansion associated with the administration of these potent antihypertensive agents may often cause these patients to develop apparent drug resistance since the thiazide diuretics are not potent enough to counteract the powerful stimulus to sodium retention caused by these antihypertensive agents. The re-evaluation of the diuretic agent at this point will usually necessitate the substitution of furosemide for thiazide or the doubling of the dose of the present loop diuretic. A working knowledge of the physiology of urine formation and the sites of action of currently available diuretic agents will enable the clinician to tailor the diuretic agent to the clinical circumstances of an individual patient and allow the clinician to rationally select a diuretic for the treatment of arterial hypertension.

Nitrendipine monotherapy in severe hypertension.

Nitrendipine is a new dihydropyridine derivative developed specifically for the treatment of hypertension. Oral nitrendipine was administered to twelve patients with severe hypertension (diastolic blood pressure greater than 114 mm/Hg). All antihypertensive drugs were discontinued at least 72 hours prior to nitrendipine administration. The initial dose of nitrendipine was 5 mgs. orally twice daily which was titrated at 2 to 5 day intervals up to a maximum dose of 40 mgs. twice a day. Average pretreatment blood pressure (+/- SD) was 194/118 (28/3) mm/Hg and was 191/122 (25/9) mm/Hg standing. After 7 to 10 days of nitrendipine monotherapy, the average blood pressure had decreased to 170/102 (20/9) mm/Hg supine and 167/106 (19/8) mm/Hg standing. Thirty days of nitrendipine therapy resulted in a further decrease of average blood pressure to 159/96 (18/7) mm/Hg supine and 154/99 (12/12) mm/Hg standing. Average supine pulse (+/- SD) increased from 79.0 (13.9) to 90 (15.7) beats/min. after 7-10 days and to 82 (17) beats/min. after 30 days of therapy. The average total daily dose of nitrendipine was 47.5 mgs. after 30 days. Side effects were minimal and the medication was well tolerated by most patients. It was concluded that nitrendipine is a potent and effective antihypertensive agent in patients with severe hypertension.

Pentoxifylline in the treatment of vascular impotence--case reports.

Vascular impotence is a common medical problem for which available therapies are limited. Three impotent patients observed in the authors' practice who were receiving pentoxifylline for treatment of claudication of the lower extremities spontaneously reported improved sexual function. A controlled trial of pentoxifylline for vascular impotence may be warranted.