A placebo-controlled dose-response study of felodipine extended release in hypertensive patients

This placebo-controlled study assessed antihypertensive effect and tolerability of two dose levels of an extended release (ER) formulation of felodipine (Plendil), given once daily to patients in primary health care. The patients had mild to moderate hypertension and were randomized to receive felodipine ER (FER) 20 mg (n = 50), FER 10 mg (n = 50), or placebo (n = 51) in a 4-week, double-blind, parallel-group multicenter study. After 4 weeks, the 24-h reduction in supine diastolic BP (DBP) was greater (p less than 0.01) in both FER groups (7 +/- 6 and 8 +/- 5 mm Hg) than in the placebo group (4 +/- 6 mm Hg). The 24-h reduction in supine systolic BP (SBP) was greater (p less than 0.01) in the FER 20-mg group (14 +/- 11 mm Hg), but not in the FER 10-mg group, than in the placebo group (8 +/- 11 mm Hg). No significant difference in blood pressure (BP) was found between FER 10 and 20 mg. Heart rate (HR) did not differ between any of the groups, nor did body weight or routine laboratory parameters. During felodipine treatment, 17 patients (12 receiving FER 20 mg) were withdrawn mostly because of vasodilatory side effects such as headache and ankle edema. We conclude that FER 10 mg and 20 mg once daily had an antihypertensive 24-h effect and that FER 10 mg may be more suitable as initial dose.     

Smooth blood pressure control obtained with extended-release felodipine in elderly patients with hypertension: evaluation by 24-hour ambulatory blood pressure monitoring

OBJECTIVE: To assess, by smoothness index (SI), distribution of the antihypertensive effect of extended-release (ER) felodipine over 24 hours in elderly patients with hypertension. METHODS: After a 4-week washout phase, 35 elderly patients (mean age 69 +/- 4 years) with mild-to-moderate hypertension received 2 weeks' treatment with ER felodipine 5mg once daily. The dosage of ER felodipine was doubled to 10 mg/day and given for a further 2 weeks in non-responders (sitting clinic blood pressure > 140/90mm Hg). The study had an open-label design with no placebo control. After each period, clinic and ambulatory blood pressures were measured. Trough-to-peak (T/P) ratio was computed by dividing the blood pressure (BP) change at trough (22 to 24 hours after drug intake) by the change at peak (2 adjacent hours with a maximal BP reduction between the second and eighth hour after drug intake). SI was calculated as the ratio between the average of the 24, hourly, treatment-induced BP changes and its standard deviation. RESULTS: After the initial 2-week treatment period, clinic and 24-hour ambulatory BP values were higher in non-responders (145 +/- 11/87 +/- 8 and 135 +/- 17/80 +/- 6mm Hg, respectively) than in responders (133 +/- 6/81 +/- 3 and 130 +/- 9/77 +/- 7mm Hg). In non-responders, clinic and 24-hour BP values were lowered after a further 2 weeks of treatment with ER felodipine 10 mg/day (128 +/- 11/78 +/- 6 and 128 +/- 12/75 +/- 5mm Hg). SI was high in responders (0.8 +/- 0.8/0.7 +/- 0.7 for systolic/diastolic BP) and low in non-responders (0.5 +/- 0.6/0.3 +/- 0.6) during the first 2-week treatment period. It increased in non-responders after an additional 2 weeks of treatment with ER felodipine 10 mg/day (1.0 +/- 0.8/0.7 +/- 0.6). Median T/P ratios were 0.73 and 0.61 (systolic BP and diastolic BP) in responders and 0.41 and 0.61 in non-responders after 2 weeks of treatment. At variance with SI, T/P ratios did not increase in non-responders after doubling the dosage of ER felodipine (0.34 and 0.18). ER felodipine did not increase 24-hour heart rate. A total of nine adverse events were recorded in six patients (17%), but no patients withdrew from the study. CONCLUSION: ER felodipine 5 to 10 mg/day smoothly and safely reduces 24-hour ambulatory BP in elderly patients with hypertension.     

Antihypertensive efficacy of the calcium-antagonist felodipine in patients with persisting hypertension on beta-adrenoceptor blocker therapy. The Canadian Felodipine Study Group.

1. The antihypertensive efficacy of two different doses of the calcium antagonist felodipine was evaluated in patients with hypertension persisting despite beta-adrenoceptor blocker therapy. Following a single-blind placebo period of 4 weeks, patients were randomized to placebo (n = 36), felodipine 5 mg twice daily (n = 39) and felodipine 10 mg twice daily (n = 35) for another 4 weeks. beta-adrenoceptor blocker therapy remained unchanged throughout the study. 2. Effects on blood pressure (BP) were evaluated after the first dose and after chronic dosing at 2 h after dosing and the end of the dosing interval (12 h). 3. Felodipine decreased systolic and diastolic BP by 30-35/20-25 mm Hg at 2 h. These decreases were similar after acute and chronic treatment. Twelve hours after dosing, decreases of 15-20/10-15 mm Hg were observed compared to 10/5 mm Hg on placebo, and half of the patients still had a controlled BP (supine diastolic BP less than 90 mm Hg). BP responses were rather similar for both doses of felodipine at 2 and 12 h. 4. Multiple regression analysis showed that both initial BP level and plasma felodipine concentrations were significant predictors of the BP response to felodipine, but age was not. 5. Adverse effects attributed to felodipine were mainly related to vascular symptoms (primarily flushing and ankle swelling); these occurred in about 30% of patients, and were pronounced in three patients (4%). 6. Felodipine is therefore highly effective in lowering BP of hypertensive patients on chronic beta-adrenoceptor blocker therapy, with no evidence for a gradual lowering of the BP or for development of tolerance. Both initial BP level and plasma concentrations are better indicators of antihypertensive efficacy of this calcium antagonist than age.     

Comparison of once daily felodipine 10 mg ER and hydrochlorothiazide 25 mg in the treatment of mild to moderate hypertension

Summary The efficacy of extended release felodipine 10 mg (ER) o.d., a new dihydropyridine calcium antagonist, and 25 mg hydrochlorothiazide (HCTZ) o.d. have been compared in a randomized, double-blind, crossover trial in 28 mildly to moderately hypertensive subjects (supine diastolic blood pressure, BP, 95 mm Hg and 110 mm Hg on three separate occasions).Both drugs significantly reduced systolic and diastolic BP in the sitting position felodipine from 157.1/93.8 mm Hg at baseline to 133/78.9 mm Hg 2.5 h after medication and to 138/82.7 mm Hg after 2 weeks of treatment, and HCTZ from 156/95.6 mm Hg to 147/88.4 mm Hg 2.5 h after medication and to 149/89.5 mm Hg also after 2 weeks.A decrease of the same magnitude in standing systolic and diastolic BP was observed after both treatment regimens with the exception of diastolic BP 2.5 h after dosing with HCTZ, which was not significantly lower. At all times (2.5 h and 2 weeks), the reduction in systolic and diastolic BP was greater after felodipine compared to HCTZ. Heart rate was significantly increased after felodipine in both the sitting and standing positions, and both 2.5 h following medication and after 2 weeks of treatment. The difference between the regimens was significant only 2.5 h after dosing. Overall, felodipine 10 mg ER o.d. was superior to 25 mg HCTZ o.d. in lowering BP.Presented in part at the Vth Scientific Meeting of the American Society of Hypertension, 17–20 May 1990, New York     

Beta-adrenergic receptors and reflex tachycardia after single and repeated felodipine administration in essential hypertension.

To verify the possible contribution of beta-adrenergic receptor down-regulation to the reversal of reflex tachycardia during chronic treatment with a dihydropyridine calcium antagonist, 11 hypertensive patients were studied with noninvasive blood pressure (BP) and heart rate (HR) monitoring after a placebo period, and on the first and seventh day of felodipine administration, 5 mg twice daily. Plasma catecholamines and neutrophil beta-adrenergic receptors were measured on the first and seventh day of treatment, immediately before and 2 h after drug administration. The first administration of felodipine was followed by a significant drop in BP (peak reduction in mean BP 24 +/- 7 mm Hg), lasting 6 h and mirrored by reflex tachycardia (peak increase in HR 14 +/- 9 beats/min). On the morning of the seventh day, 12 h after the previous felodipine administration, mean BP (MBP) was 16 mm Hg lower than on the last placebo day, while HR was unchanged. The next administration of felodipine was followed by a smaller drop in BP (MBP - 15 +/- 7 mm Hg; NS vs. placebo), while reflex tachycardia was the same as after acute felodipine (HR 13 +/- 8 beats/min; p less than 0.05 vs. placebo, NS vs. acute administration). Plasma noradrenaline concentration increased after both acute and chronic administration (p less than 0.0001), and preadministration values were highest on day 7 (p less than 0.05). Neutrophil beta-adrenergic receptor density and affinity did not change either acutely or chronically. This study gives both indirect and direct evidence that beta-adrenoceptor down-regulation does not occur during repeated felodipine administration in hypertension. Reflex tachycardia is not abolished, but is reset to lower BP levels.     

Felodipine ER formulation in the treatment of mild hypertension: efficacy and tolerability vs placebo.

1. Felodipine is a new calcium-antagonist dihydropyridine derivative with a high degree of selectivity for smooth muscle of arteriolar resistance vessels, as opposed to cardiac cells. 2. In this double-blind, cross-over study the antihypertensive efficacy and tolerability of the new extended release (ER) formulation of felodipine 10 mg, once daily, in patients with mild essential hypertension was evaluated. After a 4-week single-blind placebo period 28 patients (15 males; mean age 48 +/- 12 years) were randomized to receive felodipine 10 mg ER once daily or placebo for 4 weeks and the alternative treatment for a further 4 weeks. Supine blood pressure and heart rate were measured in the out-patients department every 2 weeks, 22-24 h after the last drug administration. 3. Felodipine 10 mg ER induced a significant reduction in blood pressure in comparison with placebo (from 149 +/- 16/97 +/- 6 to 140 +/- 12/89 +/- 6 mm Hg). Heart rate remained unchanged. Seven patients dropped-out; five during felodipine ER administration and two during placebo. 4. A once daily dose of felodipine ER significantly reduces blood pressure in mild hypertensive patients 22-24 h after administration. It is well tolerated and the adverse events are related to its pharmacodynamic effects.     

Pharmacokinetic and antihypertensive profile of amlodipine and felodipine-ER in younger versus older patients with hypertension

To evaluate the impact of age on the pharmacokinetics and blood pressure (BP) responses of a dihydropyridine (DHP) with large versus small first-pass metabolism in hypertensive subjects, younger (n = 28) and older (n = 35) patients with hypertension were randomized to placebo, felodipine-ER 5 mg/d, or amlodipine 5 mg/d. In the young subjects, the first dose of either DHP did not decrease BP and chronic dosing decreased BP by approximately 10 mm Hg, which had disappeared by 24 hours. In the older group, felodipine-ER decreased systolic BP by approximately 10 mm Hg after the first dose and by approximately 20 mm Hg after chronic dosing, which had disappeared after 24 hours. The first dose of amlodipine caused a gradual fall in BP and chronic dosing by approximately 20 mm Hg and still by approximately 10 mm Hg at 120 hours. Older subjects showed approximately 30% higher area under the concentration–time curves and plasma concentrations of felodipine and amlodipine, but (apparent) elimination half-lives did not differ between younger and older subjects. The chronic antihypertensive responses correlated well with both plasma levels and pretreatment BP. Age has only a modest impact on the pharmacokinetics of amlodipine and felodipine-ER but markedly affects the BP response to the first dose of either DHP and the duration of action after chronic dosing of amlodipine.     

A dose-finding, placebo-controlled study on extended-release felodipine once daily in treatment of hypertension

Hypertensive patients received a beta-blocker plus placebo once daily for 4 weeks. If their diastolic blood pressure (DBP) was then 95-115 mm Hg, they were randomized to receive, in addition to the beta-blocker, placebo (n = 36), felodipine-extended release (ER) 10 mg (n = 36), or felodipine-ER 20 mg (n = 37) in a 4-week double-blind parallel-group trial. All medication was administered once daily and, when BP was measured 24 h after the last dose, felodipine-ER 10 mg reduced DBP by 14 +/- 9 mm Hg (mean +/- SD) from a mean of 103 mm Hg and felodipine-ER 20 mg reduced DBP by 18 +/- 9 mm Gg from 101 mm Hg. The reductions in DBP with both doses of felodipine were greater than reductions with placebo (5 +/- 8 mm Hg, from 102 mm Hg--both p less than 0.001). At the end of the study, 21% of patients receiving placebo had a DBP less than or equal to 90 mm Hg. In contrast, 69% of patients receiving felodipine-ER 10 mg and 82% receiving 20 mg attained this level. More than 90% of patients receiving 10 mg felodipine-ER once daily had a reduction in DBP greater than 5 mm Hg 24 h postdose. Felodipine-ER was well tolerated. Felodipine-ER once daily is an effective antihypertensive drug for patients who require therapy in addition to a beta-blocker; the tolerability in this study was good, and a starting dose greater than 10 mg once daily is not indicated.     

Pharmacokinetics and blood pressure effects of felodipine in elderly hypertensive patients. A comparison with young healthy subjects

The pharmacokinetics and antihypertensive effects of felodipine, a new dihydropyridine calcium channel blocker, were studied in elderly hypertensive patients, 67 to 79 years of age and in young healthy subjects, 20 to 34 years of age following oral administration of 5 mg twice daily to steady-state. A single intravenous dose of 3H-felodipine (0.04mg) was given together with the oral dose on the study day. Cmax (17 nmol/L), Cmin (5 nmol/L) and AUC (82 nmol/L.h) were 3 times higher in the elderly than in the young subjects. Systemic availability was about 15% in both groups. Plasma clearance (CL) was reduced from 56.1 L/h in the young to 25.4 L/h in the elderly. There was no effect of age on the volume of distribution at steady-state (Vss). Reduced hepatic blood flow and enzyme activity or increased gut wall metabolism are possible reasons for the altered pharmacokinetics in the elderly. Blood pressure was reduced in the elderly from 190/99 to 177/91 mm Hg 12 hours after 5mg felodipine during twice daily dosage. The effect on blood pressure correlated with plasma concentrations of felodipine.     

Acute and steady-state pharmacokinetics and antihypertensive effects of felodipine in patients with normal and impaired renal function

Eighteen patients (14 men and 4 women, aged 36-74 years) treated with metoprolol for a month were included in the study. Twelve had impaired renal function (IRF) with a glomerular filtration rate (GFR) of 7.5-77.1 mL/min and six having normal renal function (NRF) with a GFR of 84.9-113.0 mL/min. Plasma and urine concentrations of felodipine and metabolites, heart rate, and blood pressure were recorded over 24 hours on day 1 after an oral dose of 10 mg felodipine and 0.04 mg 3H-felodipine IV and repeated on day 29 during continuous treatment with felodipine, 10 mg bid. The bioavailability of the oral dose on day 1 and day 29 was 13% and 12.5%, respectively. The terminal plasma half-life (t1/2) on day 29 was 22 hours and systemic clearance was 490 mL/min on day 1 and 434 mL/min on day 29 (NS). There were no differences in these parameters between NRF and IRF. The protein binding determined by equilibrium dialysis in the six patients with the lowest GFR was 99.74% on day 1 and 99.73% on day 29 and did not differ significantly from previously reported values in healthy subjects. The mean supine blood pressure before the acute dose of felodipine was 164/96 mm Hg in the IRF patients and 145/95 mm Hg in the NRF patients. A maximum decrease of 37/22 mm Hg and 32/19 mm Hg, respectively, was seen within 1.5 hours after dose and at 12 hours the reduction was 12/9 and 15/10 mm Hg, respectively, compared to baseline values. At steady state the morning blood pressure before dose was 152/87 mm Hg in the IRF patients and 129/86 mm Hg in the NRF patients. Similar maximum decreases and effects at 12 hours were seen after dose on day 29 as on day 1. Data on the effect on diastolic blood pressure and plasma felodipine concentrations were well fitted to the Emax model. The maximum reduction in diastolic blood pressure using this model was 27% and the plasma concentration leading to 50% of the maximum effect was 6.2 nmol/L. In conclusion, renal disease does not affect the pharmacokinetics of felodipine. The pharmacokinetic and pharmacodynamic effects of felodipine are not altered during steady state. The renal excretion of inactive metabolites is reduced in IRF. However, the accumulation of metabolites in the blood does not affect the protein binding or the clearance of felodipine. No dosage adjustment of felodipine seems to be necessary in patients with hypertension and renal impairment.     

Felodipine extended release in mild to moderate hypertension

A multi-centre study was carried out to examine the antihypertensive effect and adverse event profile of felodipine in an extended-release (ER) formulation given once daily as monotherapy. Doses of 5 mg, 10 mg or 20 mg felodipine ER were compared with placebo in 183 patients with mild or moderate hypertension. All antihypertensive medication was discontinued on entering a 4-week placebo run-in period. If, at the end of the run-in period, supine diastolic blood pressure was in the range greater than 95 less than 120 mmHg, patients were randomly allocated to double-blind treatment with felodipine, 5 mg, 10 mg or 20 mg, or placebo, to be taken once daily for 4 weeks. Supine and standing blood pressure, heart rate and body weight were measured every 2 weeks during the trial. Assessments were made 24 hours after intake of the study drug. Adverse events were recorded at each review. Over the 4-week treatment period, a dose-related decrease in supine diastolic blood pressure was observed, this reduction occurring already during the first 2 weeks of active treatment. In the placebo group and the felodipine 5 mg, 10 mg and 20 mg groups, supine blood pressure (systolic/diastolic) decreased by 7/6 mmHg, 9/8 mmHg, 12/10 mmHg and 14/11 mmHg, respectively. Supine diastolic blood pressure reduction in the felodipine 10 mg group and both systolic and diastolic blood pressure reductions in the 20 mg group were significantly greater than with placebo. Standing diastolic blood pressure reduction was significantly greater in all three dose groups on felodipine compared with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)     

Felodipine/metoprolol: a review of the fixed dose controlled release formulation in the management of essential hypertension

The main objective of fixed dose combination therapy for hypertension is to improve blood pressure (BP) control with lower, better tolerated dosages of 2 antihypertensives rather than higher dosages of a single agent. Felodipine and metoprolol lower BP via different, but complementary, mechanisms and controlled release formulations of these 2 drugs are available as a fixed dose combination, felodipine/metoprolol. In clinical trials in patients with hypertension, felodipine/metoprolol was significantly more effective than placebo and the respective monotherapies administered at the same dosages. Mean BP was reduced to < 155/90 mm Hg in patients treated with combination therapy and controlled in approximately 70% of patients. In one study that titrated dosages to effect, fewer felodipine/metoprolol than felodipine or metoprolol monotherapy recipients required dosage increases to achieve BP control (45 vs 60 and 67%, respectively). Data from double blind comparative studies show that the antihypertensive efficacy of felodipine/metoprolol 5 to 10/50 to 100 mg/day is significantly greater than that of enalapril monotherapy or captopril plus hydrochlorothiazide and equivalent to nifedipine/atenolol and amlodipine. In comparisons with enalapril, fewer felodipine/metoprolol than enalapril recipients required dosage titration to achieve BP control. Compared with amlodipine, felodipine/metoprolol significantly reduced mean 24-hour average BP (8.9/5.5 vs 14.4/9.5 mm Hg after 6 weeks; p < 0.001). Both treatments preserved diurnal rhythm. Long term follow-up studies show that the antihypertensive effect of felodipine/metoprolol occurs mostly during the first month of treatment with small additional decreases in BP being observed in the second and third months, and a relatively constant effect thereafter. According to a validated questionnaire, quality of life was relatively similar during 12 weeks treatment with felodipine/metoprolol, enalapril or placebo. In a retrospective pharmacoeconomic analysis conducted in Sweden, felodipine/metoprolol was more cost effective than enalapril as initial treatment for hypertension. Peripheral oedema, headache and flushing were the most commonly reported adverse events with felodipine/metoprolol and felodipine monotherapy, whereas dizziness, fatigue, headache and respiratory infection were more frequent with metoprolol monotherapy. Dose-dependent adverse events such as oedema may occur less often in patients taking lower dosages in combination than in those taking higher dosages of felodipine monotherapy. Thus, patients with hypertension treated with felodipine/metoprolol experience greater control of BP, with less need for dosage titration, than those treated with felodipine, metoprolol or enalapril monotherapy. Importantly this greater efficacy does not appear to be associated with a higher incidence of adverse events relative to monotherapy. Additionally, in short term studies felodipine/metoprolol had a similar (minimal) effect on QOL to enalapril monotherapy but was more cost effective.     

The effect of intravenous enalaprilat (MK-422) administration in patients with mild to moderate essential hypertension

The antihypertensive effect of enalaprilat (MK-422), an intravenous (IV), nonsulfhydryl converting-enzyme inhibitor, was evaluated in a double-blind study of 14 patients with mild to moderate hypertension. The seven patients in the treatment group initially received IV enalaprilat 1.25 mg q6h for 24 hours. Thereafter, responding patients (diastolic blood pressure [BP] less than or equal to 95 mm Hg) continued receiving this dose q6h for an additional 24 hours, whereas nonresponding patients were increased to IV enalaprilat 5 mg q6h for another 24 hours. Baseline BP for enalaprilat was 161 +/- 5/107 +/- 2 mm Hg (+/- SEM), and for placebo it was 150 +/- 5/103 +/- 2 mm Hg. Within the first 60 minutes, a significant reduction in both systolic and diastolic BP was noted in the enalaprilat group (P less than .05), without significant changes occurring in the placebo group. Although there was a gradual decline in both systolic and diastolic BP throughout the 48-hour study period in the placebo group, systolic and diastolic BP reduction was greater in the enalaprilat group, reaching a maximal decrease of 133 +/- 3/87 +/- 3 mm Hg. Adverse side effects did not occur in any patient.     

Antihypertensive efficacy and tolerability of a fixed combination of metoprolol and felodipine in comparison with the individual substances in monotherapy. The Swedish/United Kingdom Study Group.

In this double-blind, randomized, parallel-group study, the aim was to compare the efficacy and tolerability of a new fixed combination of felodipine and metoprolol with the individual components in monotherapy. After a placebo period of 4 weeks, 159 patients with mild to moderate essential hypertension were randomized to extended-release formulations of either felodipine plus metoprolol 10 + 100 mg (FM), felodipine 10 mg (F), or metoprolol 100 mg (M) once daily if supine diastolic blood pressure greater than 95 mm Hg. After 12 weeks of active treatment, the reductions in supine blood pressure (24 h after dosing) were 20/14, 13/10, and 11/8 mm Hg for FM, F, and M, respectively. The difference in change was 7/4 mm Hg (p = 0.004/p = 0.006) and 8/5 mm Hg (p = 0.0002/p less than 0.0001) for the fixed combination and F or M, respectively. Blood pressure control (diastolic blood pressure less than 90 mm Hg after 12 weeks) was significantly better for the combination than for F and M, i.e., 71%, 49% (p = 0.008), and 34% (p = 0.004), respectively. Adverse experiences were those to be expected from previous studies with felodipine and metoprolol and did not differ in frequency between groups. It can be concluded that a fixed combination of metoprolol and felodipine has a clinically relevant and significantly better blood pressure reduction 24 h postdose than the individual substances in monotherapy, without decreased tolerability.     

Effects of felodipine on pacing-induced angina pectoris

We determined hemodynamics and myocardial lactate extraction in 11 patients with severe coronary disease after 0.010 (D1), 0.015 (D2), and 0.025 nmol/min (D3) of the arteriolar dilator felodipine during pacing-induced angina pectoris. Plasma concentrations of felodipine after the 3 doses were 12 (5), 25 (6) and 43 (8) nmol/ L, respectively. At corresponding pacing rates, mean blood pressure fell from 126 (24) to 90 (15) mm Hg at D3 (p less than 0.01) and pulmonary capillary wedge pressure was reduced from 14 (10) to 9 (8) mm Hg (p less than 0.05). Cardiac output increased at all three doses (p less than 0.01). The reduction of systemic vascular resistance at D3 was 49% (p less than 0.01) and of coronary vascular resistance 35% (p less than 0.05). At D1, there was no change in lactate extraction, while 8/10 lactate producers improved at D2 and D3. ST depression was diminished at all three doses (p less than 0.05) at the control pacing rate. During maximal pacing rate at D3, the myocardial oxygen consumption was 14% above control level (N.S.). Thus, felodipine was beneficial in most patients at higher dosage. Ventricular unloading and improved coronary perfusion might explain some of these positive effects.     

Treatment of essential hypertension with felodipine in combination with a diuretic

Summary In a double-blind cross-over study, the effect on blood pressure (BP), heart rate (HR) and plasma noradrenaline concentration (pNA) of placebo or felodipine given in addition to hydrochlorothiazide was studied in 12 male patients with essential hypertension, not satisfactorily controlled with the diuretic alone. The first dose of felodipine decreased BP and increased HR for about 6 h. After 4 weeks of treatment with felodipine, BP was reduced for 24 h, whereas HR was only transiently increased. The elimination half-life of felodipine was about 23 h. The plasma noradrenaline concentration increased after felodipine and serum uric acid decreased. Side-effects were few and usually mild.     

Vascular pressor responses in treated and untreated essential hypertension.

Thirty-seven essential hypertensives received placebo for 3 weeks followed by nifedipine retard (n = 14) or enalapril (n = 13) or doxazosin (n = 10) as monotherapy for 6 weeks and attended study days to evaluate the effects of placebo, first dose, and chronic (1-6 weeks) treatment. On each study day, pressor responses to i.v. infusions of phenylephrine (PE) and angiotensin II (AII) were measured 1.5-3 h after drug administration and the derived PD20 values (dose required to increase mean blood pressure by 20 mm Hg) compared. Each treatment produced comparable reductions in BP. Nifedipine significantly attenuated the pressor responses to AII and PE: for AII, the mean PD20 (ng/kg/min) increased from 8.2 (placebo) to 9.9 (first dose), 13.9 (1 week), and 17.4 (6 weeks). Pressor responsiveness to both AII and PE was unchanged following enalapril: for PE, the mean PD20 (micrograms/kg/min) was 2.1 (placebo), 1.5 (first dose), and 1.5 (6 weeks). Doxazosin produced rightward shifts of the PE pressor dose-response curves but had no effect on responses to AII. The relationship between the simultaneous BP and HR changes during the infusion of PE was used as an index of cardiac baroreflex activity. In contrast to enalapril and doxazosin, which had no effect, nifedipine reduced the slope of the HR/BP relationship from -0.62 (placebo) to -0.38 (first dose) and -0.31 beats/min/mm Hg (6 weeks). For comparable reductions in BP, doxazosin only affects adrenergic mechanisms whereas nifedipine affects both adrenergic and non-adrenergically mediated vasoconstriction. The ACE inhibitor enalapril had no effect on pressor responses to AII and PE.     

Antihypertensive therapy with once-daily administration of terazosin, a new alpha 1-adrenergic-receptor blocker

The antihypertensive activity of terazosin, an investigational alpha 1-adrenergic-receptor blocker, and its effect on blood lipids were compared with placebo in a double-blind study. After a 3-week placebo baseline period, patients were randomized to receive terazosin (n = 22) or placebo (n = 16). The dose of terazosin was titrated over 2 weeks to a maintenance dosage of 10 mg once daily for 4 weeks. Antihypertensive efficacy was assessed: (1) at the end of the 24-hour dosing interval by comparing the average blood pressure (BP) after 3 and 4 weeks of maintenance therapy to the average BP after 2 and 3 weeks of placebo therapy, and (2) for 3 hours after drug ingestion at the final visit in comparison to the predose BP at that visit. At the end of the 24-hour dosing interval, 10 mg of terazosin reduced the mean supine systolic BP from 155.6 to 152.2 mm Hg and mean supine diastolic BP from 101.9 to 99.0 mm Hg (p less than 0.05). During the 3 hours after drug ingestion, mean supine systolic and diastolic pressures decreased maximally from 151.8 to 142.7 mm Hg (p less than 0.05) and from 99.5 to 91.0 mm Hg (p less than 0.05) respectively. No supine BP reduction differed significantly from the placebo response. During terazosin therapy there was a nonsignificant increase in mean body weight of 1.4 +/- 2.9 kg and no change in blood lipids. Thus the drug demonstrated greater antihypertensive activity 1-3 hours after ingestion than at the end of the 24-hour dosing interval.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antihypertensive effect of trimepranol, a new beta-blocking agent.

Trimepranol (TMP) is a new propranolol-like, non-selective beta-adrenoreceptor blocking drug. Its antihypertensive effect versus placebo was evaluated in a double-blind corss-over study in 25 ambulatory patients, whose supine diastolic blood pressure (BP) was at least 95 mm Hg. After four weeks treatment with placebo, the dose of TMP was titrated weekly until the supine diastolic BP was below 95 mm Hg or intolerable side effects occurred. The trimepranol dose thus determined was 10 mg bid for three patients, 20 mg bid for twelve patients and 40 mg bid for ten patients. The subsequent double-blind cross-over study consisted of two six weeks treatment periods, either with trimepranol followed by placebo (Group I) or in reverse order (Group II). BP and heart rate at the end of these periods were compared. Supine BP fell from 156 +/- 3/105 +/- 2 mm Hg at the end of placebo periods to 140 +/- 2/93 +/- 1 mm Hg (p less than 0.001) for systolic and diastolic BP at the end of trimepranol periods, when the data of Groups I and II are pooled. In 19 out of 25 patients, supine diastolic BP declined below 95 mmHg during the trimepranol period. A statistically significant correlation was found between the antihypertensive and bradycardic effects of trimepranol. Mild side effects occurred in the heart volumes of the patients. We conclude that bid trimepranol is an effective antihypertensive agent.     

Antihypertensive effect of lisinopril assessed by 24-hour ambulatory monitoring: a double-blind, placebo-controlled, cross-over study.

The antihypertensive effect of the angiotensin-converting enzyme (ACE) inhibitor lisinopril administered in a single dose of 20 mg was evaluated by ambulatory blood pressure monitoring (ABPM) in a double-blind, placebo-controlled, cross-over study. Twenty-four patients (21 men and 3 women, mean age 52 +/- 6 years) with mild to moderate hypertension were included in the study and randomly assigned to two consecutive treatments with lisinopril 20 mg and placebo, each administered for 4 weeks. On the last day of each treatment, BP was assessed by noninvasive 24-h ABPM. BP was significantly lower after lisinopril than after placebo in a 24-h period (mean 24-h systolic BP (SBP) with lisinopril 120 +/- 7 mm Hg and with placebo 135 +/- 9 mm Hg; mean day SBP with lisinopril 125 +/- 3 mm Hg and with placebo 142 +/- 5 mm Hg; mean night SBP with lisinopril 112 +/- 4 mm Hg and with placebo 124 +/- 6 mm Hg; mean 24-h diastolic BP (DBP) with lisinopril 76 +/- 6 mm Hg, and with placebo 87 +/- 8 mm Hg; mean day DBP with lisinopril 80 +/- 3 mm Hg and with placebo 93 +/- 4 mm Hg; mean night DBP with lisinopril 69 +/- 2 mm Hg and with placebo 79 +/- 5 mm Hg, p less than 0.001). Mean 24-h, mean day, and mean night heart rate (HR) did not differ significantly between placebo and lisinopril treatments. Repeated-measures analysis of variance (ANOVA) showed a significant influence on SBP (p less than 0.001) and DBP (p less than 0.001) throughout the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)