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.     

Antihypertensive effect of felodipine or hydralazine when added to beta-blocker therapy

In a double-blind randomized study, hydralazine (n = 59) or the new dihydropyridine calcium antagonist felodipine (n = 61) was added to previous treatment with beta-adrenoceptor blocking agents in a group of 120 patients with essential hypertension. Active treatment with either hydralazine or felodipine was given for 8 weeks after a 4-week placebo run-in period, at the end of which all patients had supine diastolic blood pressures greater than 95 mm Hg. Assessment of the results according to the intention to treat principle showed that felodipine was significantly more effective than hydralazine at the doses employed, reducing systolic blood pressure 10-19 mm Hg more than hydralazine and reducing diastolic blood pressure 5-11 mm Hg more than hydralazine (95% confidence intervals). The number of patients complaining of side effects, the number of complaints, and the number of patients that had to be withdrawn from treatment were numerically higher during treatment with hydralazine than with felodipine, but these differences were not statistically significant. Against this background it is concluded that felodipine is superior to hydralazine when added to an antihypertensive regimen consisting of beta-adrenoceptor blocking agents.     

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.     

Control of hypertension in elderly patients with felodipine and metoprolol: a double-blind, placebo-controlled clinical trial.

1. Forty-nine patients aged 65-80 years, whose Phase V diastolic blood pressure (dBP) was above 95 mmHg after 4 weeks open treatment with metoprolol 50 mg twice daily were randomized to receive, double-blind, the calcium antagonist felodipine (n = 32) 2.5 mg twice daily or placebo (n = 17) in addition to metoprolol for 2 weeks. If the dBP remained greater than 95 mmHg, the dose of felodipine or placebo was doubled for a further 2 weeks; if the dBP was still greater than 95 mmHg, the dose of felodipine was doubled again to 10 mg twice daily or the corresponding placebo dose given. The duration of the double-blind period was 6 weeks, all patients receiving metoprolol 50 mg twice daily throughout. 2. At the end of the double-blind period, the seated dBP was reduced from 103 +/- 5 (mean +/- s.d.) to 88 +/- 7 mmHg (P less than 0.001) by felodipine and from 105 +/- 100 +/- 11 mmHg (NS) by placebo. The differences between these reductions (P less than 0.01) and between the final dBPs (P less than 0.001) were significant. Eighty-nine per cent of patients receiving felodipine and 33% of those receiving placebo (P less than 0.001) had controlled (dBP less than or equal to 95 mmHg) BPs. Half (14/27 completing) of the patients receiving felodipine required 2.5 mg throughout; 9/27 needed 5 mg and 4/27 10 mg twice daily. Adverse events occurred with equal frequency in the two groups, but the profile was different.(ABSTRACT TRUNCATED AT 250 WORDS)     

Placebo-controlled trial of once-a-day isradipine monotherapy in mild to moderately severe hypertension

The efficacy and safety of once-daily dosing of isradipine, a new calcium antagonist vasodilator, was evaluated in a multicenter, placebo-controlled trial in hypertensive patients who had supine diastolic blood pressure (SDBP) 100-119 mm Hg. After a 3-week single-blind placebo washout patients randomly received either isradipine, 5 mg once daily, or a matching placebo; if SDBP remained greater than or equal to 95 mm Hg or less than or equal to 10 mm Hg below baseline at four weekly clinic visits, isradipine was increased at weekly intervals by 5 mg once daily up to 20 mg and maintained during weeks 5 and 6. At week 6 mean supine blood pressure 24 hours after dosing had declined from 163 +/- 20/105 +/- 5 (N = 78) to 146 +/- 17/92 +/- 7 mm Hg (N = 60) on isradipine, 14.5 mg once daily, and from 163 +/- 20/105 +/- 6 (N = 85) to 157 +/- 18/99 +/- 10 mm Hg (N = 64) on placebo (P less than .001 between groups). Standing blood pressure decreased from 159 +/- 20/104 +/- 8 to 144 +/- 18/93 +/- 11 mm Hg with isradipine and from 160 +/- 22/105 +/- 9 to 154 +/- 19/101 +/- 11 mm Hg with placebo (P less than .001 between groups) without signs or symptoms of postural hypotension. A SDBP less than or equal to 90 mm Hg or a greater than or equal to 10 mm Hg fall below baseline was achieved in 41 of 78 isradipine-treated (53%) and 18 of 85 placebo-treated subjects (21%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Control of blood pressure in hypertensive patients with felodipine extended release or nifedipine retard.

1. This multicentre hospital study compared the antihypertensive efficacy and the tolerability of once daily felodipine extended release (ER) with twice daily nifedipine retard (R) in hypertensive patients inadequately controlled on metoprolol monotherapy. 2. One hundred patients, aged 20-70 years, whose seated diastolic blood pressure was 100-115 mmHg after 4 to 6 weeks of metoprolol (200 mg day-1) monotherapy, were randomised, double-blind, to receive felodipine ER 10 mg once daily or nifedipine R 20 mg twice daily for 8 weeks. The dosage of felodipine or nifedipine was doubled if seated diastolic blood pressure exceeded 95 mmHg, 2 or 4 weeks after randomisation. Metoprolol 200 mg once daily was taken throughout the trial. 3. Fifty-one patients received felodipine ER and 49 nifedipine R; 46 and 45 respectively completed the 8 week trial. About half of patients on each treatment needed the higher dose. The baseline characteristics of the felodipine and nifedipine groups were generally well balanced. 4. Seated diastolic blood pressure was reduced by 17 mmHg for felodipine (24 h post-dose) and by 9 mmHg for nifedipine (12 h post-dose), a difference between treatments of 8 mmHg (95% confidence interval 5 to 12 mmHg, P less than 0.0001). The attained blood pressures at the end of the study (felodipine 90 +/- 10, mmHg, mean +/- s.d.; nifedipine 95 +/- 10) were also significantly different (95% confidence interval for the 5 mmHg difference, -9 to -1 mmHg, P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of indomethacin on the pharmacokinetics and pharmacodynamics of felodipine.

1. We studied the effects of pre-treatment with oral indomethacin (25 mg four times daily for 3 days) on the pharmacokinetics, haemodynamics and diuretic properties of oral felodipine (10 mg single dose) in 12 healthy male volunteers using a placebo controlled double-blind four-way crossover protocol. 2. Felodipine with or without indomethacin pretreatment reduced standing diastolic blood pressure (P less than 0.001) at 0.5 to 3.0 h after dosing compared with placebo or indomethacin alone. Systolic blood pressures during indomethacin treatment alone were consistently higher than the other three treatment groups (P less than 0.01), presumably due to sodium and fluid retention. 3. Felodipine and felodipine plus indomethacin produced significantly greater excretion of urine and urinary sodium, but not of urinary potassium or creatinine when compared with placebo (P less than 0.01) over an 8 h period. 4. The pharmacokinetic parameters of felodipine (Cmax, tmax, t1/2 and AUC), the concentration-response curves for blood pressure lowering effects, the reflex tachycardia, diuretic properties and side-effects profile of felodipine were not significantly altered by indomethacin pretreatment in normal volunteers.     

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.     

Double-blind study of dilevalol and captopril, both in combination with hydrochlorothiazide, in patients with moderate to severe hypertension.

Sixty-one patients (41 men, 20 women) aged 29-73 years, with moderate to severe hypertension, were enrolled in a multicentre study to compare the efficacy, safety, and tolerability of dilevalol (D) and captopril (C). At the end of the baseline period, supine diastolic blood pressure (SuDBP) was 105-140 mm Hg on hydrochlorothiazide (HCTZ) 25 mg once daily and placebo t.i.d. Patients were randomly assigned to D + HCTZ (n = 29) or C + HCTZ (n = 32) and entered phase II titration of D (100-800 mg b.i.d.) or C (12.5 mg b.i.d. to 50 mg t.i.d.). If SuDBP was greater than 99 mm Hg, hydralazine was added (25 mg once daily to 50 mg b.i.d.). If SuDBP was less than or equal to 99 mm Hg, patients entered phase III, a 3-month maintenance period. Demographic profiles were not significantly different between the two groups. Baseline supine BP (mean +/- SEM) was similar in the two groups (D + HCTZ: 182 +/- 3/112 +/- 1; C + HCTZ: 179 +/- 4/113 +/- 1 mm Hg), as was baseline standing BP (D + HCTZ: 175 +/- 3/114 +/- 2; C +/- HCTZ: 173 +/- 4/113 +/- 1 mm Hg). At the end of phase II, there were no significant differences between treatments with respect to the changes in BP from baseline.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of felodipine on haemodynamics and exercise capacity in patients with angina pectoris.

We studied the effects of adding felodipine to beta-adrenoceptor blockade on haemodynamics and exercise capacity in 14 patients with stable angina pectoris using a placebo controlled double-blind crossover protocol. Felodipine reduced supine and standing systolic pressure by 13% (P less than 0.01) and 14% (P less than 0.01) respectively and increased supine heart rate 7.4% (P less than 0.05). Felodipine at a plasma concentration of 15.5 +/- 3.0 nmol l-1 increased exercise duration by 16% (P less than 0.01) but failed to attenuate the degree of ST segment depression during exercise. The mean daily number of episodes of angina (0.53 +/- 0.16 on placebo vs 0.37 +/- 0.11 on felodipine) and mean daily GTN consumption (0.51 +/- 0.07 on placebo vs 0.36 +/- 0.12 on felodipine) were not significantly reduced (0.1 less than P greater than 0.05). These findings suggest that felodipine may provide useful additional benefits in patients with hypertension or angina pectoris, who are already receiving beta-adrenoceptor blockers.     

The effect of felodipine on forearm haemodynamics and the myogenic response of the forearm resistance vessels in normal man.

The effect of felodipine 10 mg oral solution or placebo on peripheral haemodynamics and the response of the forearm resistance vessels to venous occlusion was studied in seven normotensive individuals. Felodipine produced a significant fall in diastolic blood pressure (DBP max = -15 mm Hg), a rise in heart rate (heart rate max = +15 beats min-1) (both P less than 0.01), and an overall fall in calculated forearm vascular resistance (calculated forearm vascular resistance max = -19.6 units, P less than 0.001). Felodipine had no significant effect on the vasodilator response, but limited the vasoconstrictor response following venous occlusion. These observations suggest that felodipine is a potent vasodilator and interferes with the myogenic response of vascular smooth muscle of the forearm resistance vessels.     

Atenolol-nifedipine combinations compared to atenolol alone in hypertension: efficacy and tolerability.

1. In a double-blind, randomised, three-way-crossover study, 25 patients with sitting diastolic blood pressure between 95 and 120 mm Hg (Phase V) after 4 weeks' run-in on atenolol 50 mg twice daily, received atenolol 50 mg twice daily alone, atenolol 50 mg plus nifedipine 20 mg each twice daily and atenolol 50 mg plus nifedipine 40 mg each twice daily in three treatment periods each lasting 4 weeks. 'Washout' periods were not included. 2. The two combination treatment regimes lowered the 12 h post-dose blood pressure more effectively than did atenolol alone, but the high dose nifedipine combination was no more effective than the low dose nifedipine combination. Sitting systolic BP (+/- s.e. mean) at the end of each period was 174 +/- 5 mm Hg after the atenolol run-in, 170 +/- 5 mm Hg with atenolol alone, 156 +/- 5 mm Hg with the low dose combination and 158 +/- 4 mm Hg with the high dose combination. Corresponding diastolic BP readings were 106 +/- 2 mm Hg, 106 +/- 2 mm Hg, 97 +/- 2 mm Hg and 99 +/- 2 mm Hg respectively. 3. Side-effects tended to occur less commonly with the low dose of the fixed combination than with atenolol alone. An increased number of side-effects occurred with the 40 mg twice daily doses of nifedipine, particularly flushing/erythema, oedema of the ankles/feet, and a hot feeling in the legs. These differences did not reach significance. 4. Overall compliance was good (98 +/- 0.7 s.e. mean %) and was similar within the different treatment regimes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antihypertensive response to ketanserin: influence of race and weight

The antihypertensive effects of the 5-HT2 receptor antagonist ketanserin were evaluated in 16 patients with uncomplicated essential hypertension. Following a three week single-blind placebo treatment period, patients were randomized to receive in a double-blind manner oral ketanserin 20 mg or 40 mg twice a day for 10 weeks. In the racially mixed patient population, mean (+/- SD) seated blood pressure 12 hours after the last dose of placebo was 161 +/- 11/99 +/- 9 mm Hg and 155 +/- 19/98 +/- 10 mm Hg after ketanserin (P greater than .05). Ketanserin 20 mg twice a day did not lower blood pressure significantly. In contrast, 40 mg twice a day significantly decreased systolic blood pressure (P less than .02), and lowered diastolic blood pressure (P = .06). White patients (N = 7) showed a significant decrease in blood pressure (BP) with ketanserin treatment (158 +/- 5/98 +/- 8 vs. 147 +/- 13/92 +/- 6 mm Hg, P less than .05) while black patients (N = 9) did not (165 +/- 13/100 +/- 9 vs. 161 +/- 21/102 +/- 10 mm Hg, P greater than .05). For black patients only, significant correlations were observed between body weight and the change in diastolic BP (r = -.86, P less than .005). The racial difference in response to ketanserin could not be attributed to differences between the two groups in age, sex, body weight, pretreatment blood pressure or ketanserin dose. The nature of the racial difference in the chronic antihypertensive response to ketanserin warrants further evaluation.     

The effects of felodipine in angina pectoris

Summary The clinical response to felodipine, in addition to a beta-blocker, was evaluated and compared with placebo in this double-blind cross-over study. Twenty patients with exertional angina pectoris completed the study. Felodipine reduced the number of angina attacks and the Glyceryl Trinitrate (GTN) consumption. The median exercise capacity was increased 33% after 4 weeks' felodipine treatment compared with placebo. At maximal exercise, systolic blood pressure and rate pressure product were reduced by felodipine while no change was seen in heart rate or ST-depression. Felodipine reduced both supine and erect blood pressure. The mean supine blood pressure at rest was 138/82 mm Hg after four weeks' placebo treatment compared with 114/71 mm Hg after felodipine 5–10 mg b.i.d. Felodipine has overall a modest but significant antianginal benefit when combined with a beta-blocker.     

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.     

Serotonergic blockade compared with beta-adrenergic blockade in systemic hypertension: a double-blind comparison of ketanserin with propranolol

The safety and efficacy of ketanserin, a competitive serotonin blocking agent, and propranolol were compared in 33 patients with mild to moderate hypertension (sitting diastolic blood pressure [DBP] 95-115 mm Hg) using a placebo run-in, randomized, double-blind parallel study design. All patients received placebo for 4 weeks, then were randomized to receive increasing doses of either ketanserin (20, 40 mg twice daily) or propranolol (40, 80 mg twice daily) to achieve a goal sitting DBP less than 90 mm Hg. Patients not achieving the goal blood pressure with either drug as monotherapy, received the other drug in combination. At the end of the active monotherapy phase (week 10 of the study), propranolol demonstrated a greater decrease in DBP from baseline, as compared to ketanserin (-7.9 +/- 10.9 mm Hg with propranolol, P less than 0.05; -1.0 +/- 7.2 mm Hg with ketanserin, P = NS). Four out of 16 patients achieved goal response on propranolol, compared to 3/17 for ketanserin. With combination treatment, 9/18 patients reached the goal response; the addition of propranolol to ketanserin in non-responders resulted in further reduction of sitting DBP of -10.3 +/- 6.3 compared to monotherapy (P less than 0.001), while the addition of ketanserin to non-responders produced no significant response in sitting DBP. Propranolol showed a consistent effect in slowing heart rate. Ketanserin displayed less frequent side effects than propranolol. Propranolol used twice daily appears to be more effective than twice daily ketanserin use in patients with mild to moderate hypertension.     

Felodipine in combination with a β-adrenoceptor blocker as an effective substitute for triple therapy in severe hypertension

Summary We have studied the efficacy and tolerability of felodipine plus a -adrenoceptor blocker in 79 patients with essential hypertension previously treated with a combination of three or more anti-hypertensive agents, one of which was a -adrenoceptor blocker.After a 4-week run-in period on the same -blocker plus placebo (as a substitute for the other agents in the regimen), felodipine was added and its dose titrated to achieve a supine diastolic blood pressure or less than 90 mm Hg. This was followed by a 12-week maintenance phase in all patients, and 47 patients entered an optional long-term follow-up for an additional 9 months.The mean supine blood pressure was 149/88 mm Hg at entry and 174/108 mm Hg after the run-in phase. Felodipine significantly reduced the blood pressure to 142/85 mm Hg after dose titration and to 141/84 mm Hg after 12 weeks, 94% of patients achieving a supine diastolic blood pressure of 90 mm Hg or below. This reduction was maintained in the patients who were followed for 12 months.The adverse events recorded were usually mild, transient, and typical for an effective precapillary vasodilator. Nine of 74 patients (11%) were withdrawn in the first phase of the study because of adverse events and 5 of 47 patients were withdrawn during the long-term follow-up.These results show that the efficacy and tolerability of a combination of felodipine with a -blocker allow a simplified regimen for hypertensive patients who were previously taking three or more drugs for satisfactory blood pressure control.The Australian Felodipine Multicentre Study Group     

Antihypertensive effects of a new sustained-release formulation of nifedipine

The blood pressure response to a new sustained-release formulation of nifedipine was evaluated in an 8-week, double-blind, placebo-controlled study. Twenty-nine patients with mild essential hypertension were randomized to receive placebo (N = 9), 30 mg nifedipine (N = 10), or 60 mg nifedipine (N = 10). During treatment, 30-mg and 60-mg doses of nifedipine administered once daily decreased office blood pressures from 137/98 +/- 8/2 mm Hg and 141/98 +/- 15/2 mm Hg at baseline, respectively, to 126/89 +/- 9/7 mm Hg and 126/86 +/- 6/7 mm Hg (P less than .005). Noninvasive automatic ambulatory blood pressure monitoring demonstrated a marginally significant (P less than .10) reduction in the mean 24-hour blood pressure of 2/6 +/- 8/8 mm Hg and 5/6 +/- 9/9 mm Hg for patients taking 30 mg and 60 mg nifedipine once daily, respectively. Diastolic blood pressure load (the percentage of ambulatory diastolic blood pressure readings greater than 90 mm Hg) during 24 hours was decreased by 41% and 35%, with 30 mg and 60 mg nifedipine administered once daily, respectively. No significant dose response to nifedipine at these dose levels was observed. Although the once-daily formulation of nifedipine achieved effective control of office blood pressure, similar control was not observed in awake and 24-hour periods in all patients.     

Hydralazine and prazosin in the treatment of hypertension.

We report the results of an observer blind crossover trial in 31 patients with essential hypertension comparing the hypotensive effect of four doses of prazosin and of hydralazine used as the third step of triple therapy and additional data on the efficacy of low dose combinations of these two drugs. Both drugs had an appreciable antihypertensive effect, 1 mg of prazosin being equivalent to 12.5 mg of hydralazine. Increasing the dose of prazosin from 4 to 8 mg twice daily and hydralazine from 50 to 100 mg twice daily did not consistently reduce blood pressure. The combination of the two drugs at low doses resulted in the blood pressure of more patients being controlled (diastolic blood pressure 90 mm Hg or below) than when either drug was used alone at high dose. The symptoms reported by patients were similar for both drugs. The combination did not lead to an increased reporting frequency. The trial demonstrates one of the problems of a crossover study, namely a treatment/period interaction.     

Effect of a new calcium antagonist, tiapamil, in hypertension of the elderly.

The antihypertensive effect of a single oral dose of tiapamil (450 mg) and placebo were compared in a single blind randomized cross-over study in 10 71-86 year old hypertensive patients. Blood pressure (BP) and heart rate (HR) were recorded every 15 min for 12 h by an automatic device. Tiapamil led to a decrease in mean daytime systolic (SBP) and diastolic (DBP) BP from 171 +/- 12/98 +/- 10 mm Hg to 159 +/- 11/90 +/- 9 mm Hg (P less than 0.001) without significant variation in HR. Thereafter patients received tiapamil 450 twice daily; by the seventh day of treatment mean daytime SBP and DBP were 155 +/- 13/85 +/- 14 mm Hg (P less than 0.001 vs placebo). The hourly mean values of SBP recorded for 8/12 h (first tiapamil day) and 10/12 h (seventh tiapamil day) were significantly lower than the corresponding values after placebo. We conclude that tiapamil in the elderly exerts a sustained antihypertensive effect lasting 12 h or more, with only minor variations in HR. This effect predominates on systolic pressure and is significant from the first dose.