Efficacy and safety of the single pill combination of amlodipine 10 mg plus valsartan 160 mg in hypertensive patients not controlled by amlodipine 10 mg plus olmesartan 20 mg in free combination.

BACKGROUND AND OBJECTIVE: For patients with moderate hypertension (grade 2, defined as systolic blood pressure [SBP] 160-179 mmHg and/or diastolic blood pressure [DBP] 100-109 mmHg), current guidelines recommend initial combination therapy and rapid dose-adjustment to achieve blood pressure goal. In this study we investigated the efficacy and tolerability of the single pill combination of amlodipine 10 mg plus valsartan 160 mg (A 10 + Val 160) in patients not controlled by the free combination of amlodipine 10 mg plus olmesartan 20 mg (A 10 + O 20). METHODS: In this prospective, open-label, non-randomized trial, 257 patients with mean sitting DBP of 100-109 mmHg at trough entered a 4 week treatment phase with A 10 + O 20 in free combination once daily. Patients in whom DBP remained uncontrolled were switched in a second 4 week treatment phase to A 10 + Val 160. The primary efficacy variable was the reduction in DBP at week 8 compared to week 4 in the intent-to-treat population. RESULTS: In the total cohort, baseline SBP/DBP of 164.2 +/- 9.8/103.6 +/- 2.1 mmHg decreased by 19.2 +/- 12.4/14.1 +/- 7.4 mmHg at week 4. In patients who did not achieve BP control (n = 175), subsequent treatment with A 10 + Val 160 for 4 weeks reduced SBP from 149.6 +/- 11.1 at week 4 by 7.9 mmHg at week 8 (95% CI: 6.1-9.6, p < 0.0001) and DBP from 93.4 +/- 3.9 mmHg by 9.1 mmHg (95% confidence interval: 8.1-10.2, p < 0.0001). The combination of A 10 + Val 160 was well tolerated, and the observed adverse events (15.3% of patients in phase 2) were consistent with the known drug profiles. CONCLUSIONS: In a study designed to reflect typical clinical practice, in patients not controlled by the free combination of A 10 + O 20, the single pill combination of A 10 + Val 160 produced a statistically and clinically significant additional BP reduction and was well tolerated. Potential limitations of the design (open-label, non-controlled design, short term treatment) have to be taken into account.

Efficacy, safety and tolerability of valsartan 80 mg compared to irbesartan 150 mg in hypertensive patients on long-term hemodialysis (VALID study).

BACKGROUND: End stage renal disease (ESRD) patients mainly die of cardiovascular disease, and hypertension is regarded as the major risk factor. Valsartan is an angiotensin receptor blocker (ARB) with a well-established efficacy and safety profile in hypertensive patients, but with relatively few data in patients on hemodialysis (HD). The aim of this 2 A 5-week, open-label, multicenter, randomized cross-over study was to investigate whether valsartan (Val) 80 mg is as effective, safe and well-tolerated as irbesartan (Irb) 150 mg in patients with arterial hypertension on long-term hemodialysis. METHODS: After a wash-out of previous ARBs for 1 week, 67 patients (ITT) on long-term hemodialysis, between 18 and 80 years, with mean supine systolic blood pressure (MSupSBP) >or= 140 mmHg and < 180 mmHg were randomized to either Val 40 or Irb 75 for 1 week with forced titration to Val 80 or Irb 150 for another 4 weeks. After a second wash-out period of 1 week, patients were switched from Val to Irb or vice versa for another 5 weeks (1 week low-dose, 4 weeks target dose). The primary objective was non-inferiority of Val versus Irb on predialytic MSupSBP. Secondary objectives were predialytic MSupDBP, adverse events (AEs), laboratory abnormalities, hypotension during and after dialysis and quality of life. BP values are given as mean A+/- SD. RESULTS: Baseline BP values were 158 A+/- 11 / 78 A+/- 13 mmHg (Val) and 161 A+/- 13 / 83 A+/- 10 mmHg (Irb). The predialytic MSupSBP and MSupDBP after 4 weeks of treatment were similar in both treatment groups (Val 150 A+/- 19 / 79 A+/- 13 mmHg; Irb 151 A+/- 16 / 78 A+/- 14 mmHg). Most of the reported AEs were mild to moderate. The percentage of AEs considered by the investigator to be possibly drug-related was similar between both groups: 15.4% in the valsartan group and 20.4% in the irbesartan group. The most common AEs were nausea, muscle spasms and nasopharyngitis. Eight SAEs occurred, four in each treatment group (all not drug-related), including one death (cardiovascular insufficiency) in the Irb group. Laboratory changes were similar in both groups and not clinically relevant. The number of patients with symptomatic hypotension was similar during (9% each) as well as after dialysis (1.3% each). The quality of life data (SF-36) were comparable for each category. CONCLUSIONS: Valsartan 80 mg is as effective, safe and well tolerated as irbesartan 150 mg in hypertensive patients on chronic hemodialysis.

Combination of amlodipine 10 mg and valsartan 160 mg lowers blood pressure in patients with hypertension not controlled by an ACE inhibitor/CCB combination.

AIMS: This multicenter, open-label, single-arm trial assessed the efficacy of the combination of amlodipine 10 mg and valsartan 160 mg to provide additional blood pressure reduction and tolerability in patients with moderate hypertension not adequately responding to the combination of ramipril 5 mg and felodipine 5 mg. RESULTS: Of 133 patients treated for 5 weeks with ramipril 5 mg and felodipine 5 mg, 105 failed to achieve mean sitting systolic blood pressure <140 mmHg. These non-responders were then treated for an additional 5 weeks with amlodipine 10 mg and valsartan 160 mg, which resulted in clinically and statistically significant additional reductions in mean sitting systolic blood pressure of 15.4 mmHg (p<0.0001) and mean sitting diastolic blood pressure of 7.0 mmHg (p<0.0001). Adverse event rates were low with both treatment regimens. CONCLUSIONS: In hypertensive patients not controlled at 5 weeks by ramipril 5 mg and felodipine 5 mg, significant additional blood pressure reductions were observed after 5 weeks of treatment with amlodipine 10 mg and valsartan 160 mg. The combination of amlodipine 10 mg and valsartan 160 mg was well tolerated.

Efficacy and safety of valsartan 160/HCTZ 25 mg in fixed combination in hypertensive patients not controlled by candesartan 32 mg plus HCTZ 25 mg in free combination.

OBJECTIVE: Free combination hypertension medication is associated with a lower compliance and less persistence compared to fixed combination therapy and can, therefore, be associated with insufficient blood pressure reductions. This non-randomized study investigated whether valsartan 160 mg/hydrochlorothiazide 25 mg (Val 160/HCTZ 25) in fixed dose combination could provide additional blood pressure control in hypertensive patients not adequately controlled by the free combination of candesartan 32 mg plus HCTZ 25 mg. RESEARCH DESIGN AND METHODS: One hundred and ninety-seven patients with a mean sitting diastolic blood pressure (MSDBP) between 100 and 110 mmHg entered a 4-week treatment phase with 32 mg of candesartan in free combination with 25 mg of HCTZ once daily. One hundred and thirty-eight patients with uncontrolled BP at Week 4, entered a second 4-week treatment phase with Val160/HCTZ 25 once daily. MAIN OUTCOME MEASURES: The primary efficacy parameter was the reduction in MSDBP at trough between Week 4 and Week 8 in the intent-to-treat population. RESULTS: At baseline, MSDBP was 103.0 +/- 2.8 mmHg. After Week 4, MSDBP had decreased to 93.8 +/- 4.5 mmHg. Subsequent treatment with Val 160/HCTZ 25 for 4 weeks reduced MSDBP to 88.7 +/- 8.6 mmHg. This represented an additional decrease in MSDBP of 5.1 +/- 7.9 mmHg (p < 0.0001). Val 160/HCTZ 25 reduced mean sitting systolic BP by 3.4 +/- 13.0 mmHg (p = 0.0029). CONCLUSIONS: The fixed dose combination of valsartan 160/HCTZ 25 mg provided a statistically and clinically significant additional BP reduction in patients not controlled by the free combination of candesartan 32 mg and HCTZ 25 mg.

Antihypertensive effects of valsartan/hydrochlorothiazide combination in essential hypertension.

Fixed-dose combination therapy has received increased interest since publication of JNC-VI report and WHO/ISH guidelines 1999. We compared in a randomized, double-blind study the efficacy and tolerability of valsartan 80 mg combined with hydrochlorothiazide (HCTZ) 12.5 mg to monotherapy with either HCTZ 12.5 mg or 25 mg in patients with essential hypertension inadequately controlled by previous HCTZ 12.5 mg monotherapy. Two hundred and seventeen patients whose blood pressure (BP) control remained poor (95 mmHg < or = sitting diastolic BP < 115 mmHg) after a 4-week single-blind period with HCTZ 12.5 mg were randomized to receive either combination therapy with valsartan 80 mg plus HCTZ 12.5 mg (V/HCTZ) or monotherapy with HCTZ 12.5 mg or HCTZ 25 mg for 8 weeks. Reduction of sitting trough diastolic BP between baseline and week 8 as well as tolerability was evaluated. Reduction in trough diastolic BP was most pronounced in the V/HCTZ group (-11.3 mmHg) and significantly greater than in the HCTZ 12.5 mg group (-2.9 mmHg, p < 0.001) and the HCTZ 25 mg group (-5.7 mmHg, p < 0.001). Tolerability of study medication was comparable between all three groups. In conclusion, switching to V/HCTZ combination therapy provides an additional lowering of BP compared to dosage increase of the thiazide in patients with BP insufficiently controlled by HCTZ 12.5 mg monotherapy.

Vasorelaxation by new hybrid compounds containing dihydropyridine and pinacidil-like moieties.

The synthesis and pharmacological properties of a novel type of vasorelaxant hybrid compounds are described. The investigated compounds originate from fluorinated 4-aryl-1,4-dihydropyridines, which are known calcium channel blockers, and/or from fluorinated analogues of pinacidil, which is an opener of ATP-sensitive potassium channels. In particular, we studied the most potent hybrid, 2,6-dimethyl-3,5-dicarbomethoxy-4-(2-difluoromethoxy-5-N-(N' '-cyano-N'-1,2,2-trimethyl-propylguanidyl)-phenyl)-1, 4-dihydropyridine (4a), together with its parent compounds, the dihydropyridine 1b and the pinacidil analogue 3. In isolated rat mesenteric arteries, micromolar concentrations of 4a relaxed contractions exerted by K(+)-depolarization or by norepinephrine. The latter effect was sensitive to the potassium channel blocker glibenclamide. Micromolar 4a also inhibited [(3)H](+)-isradipine and [(3)H]P1075 binding to rat cardiac membranes, and it blocked L-type calcium channels expressed in a mammalian cell line. The respective parent compounds 1b and 3 were always more potent and more selective regarding calcium channel or potassium channel interaction, respectively. In contrast, 4a combined both effects within the same concentration range, indicating that it may represent a lead structure for a novel class of pharmacological hybrid compounds.

Dihydropyridine enantiomers block recombinant L-type Ca2+ channels by two different mechanisms.

1. The molecular basis of the state-dependent block of L-type Ca2+ channels by dihydropyridines is still poorly understood. Therefore, we studied the enantioselectivity of Ca2+ channel block by isradipine enantiomers at three holding potentials (-80, -60 and -40 mV) in Chinese hamster ovary (CHO) cells stably expressing the rabbit lung alpha1C-b-subunit. 2. The extent of enantioselectivity did not markedly change with the holding potential (IC50 ratios of 104-138), whereas the potency of both isradipine enantiomers increased with depolarisation of the holding potential. 3. In addition to its block of the peak Ca2+ channel current, Ipeak, (-)-isradipine inhibited the relative current at the end of the test pulse, the so-called Ilate, normalised to Ipeak (Ilate/Ipeak). This effect was unaffected by the holding potential and revealed distinct kinetics compared to the development of conventional block of Ipeak. 4. When these effects were studied using an alpha1C-b-mutant lacking the high-affinity dihydropyridine binding site, expressed in human embryonic kidney (HEK 293) cells, both enantiomers blocked Ilate/Ipeak to a similar degree. 5. Our data are discussed within the framework of the 'guarded receptor' and the 'modulated receptor' hypotheses. The very different properties of the block of Ilate/Ipeak compared to those of the conventional high-affinity block of Ipeak suggest the existence of an additional mechanism possibly mediated via a second, distinct binding site.

Interaction of three structurally distinct Ca2+ channel activators with single L-type Ca2+ channels.

The dihydropyridine S(-)-Bay K 8644 (Bay K), the benzoylpyrrole FPL 64176 (FPL) and the benzodiazocine CGP 48506 (CGP) are structurally unrelated L-type Ca2+ channels agonists. The aim of our study was to investigate whether these three drugs interact with different binding sites and thereby modulate the behaviour of L-type Ca2+ channels in a qualitatively different manner. Single-channel recordings were performed on CHO cells stably expressing the alpha1C-b subunit of the L-type Ca2+ channel. Mean open time and open probability were determined sweep by sweep and the effects of CGP (10(-4) M), Bay K (10(-6) M) and FPL (10(-6) M) were compared. All three compounds increased mean open time and open probability when applied alone. However, the gating pattern changes induced by each drug were qualitatively and quantitatively different. We also applied binary mixtures and analysed the resulting sweeps with respect to their gating pattern. The application of mixtures did result in a gating pattern not seen with any of the single drugs. The mixture of CGP and FPL led to a prolonged mean open time compared with each single drug. The mixture of Bay K and FPL exhibited an open probability lower than with each single drug. The mixture of CGP and Bay K increased the mean open time per sweep like Bay K, but the number of openings was similar to the level seen with CGP alone. These results cannot be explained by assuming alternative binding of the drugs to a single binding site. We therefore conclude that Bay K, CGP and FPL bind to different but interacting sites on the L-type Ca2+ channel.

Increased availability and open probability of single L-type calcium channels from failing compared with nonfailing human ventricle.

BACKGROUND: The role of the L-type calcium channel in human heart failure is unclear, on the basis of previous whole-cell recordings. METHODS AND RESULTS: We investigated the properties of L-type calcium channels in left ventricular myocytes isolated from nonfailing donor hearts (n= 16 cells) or failing hearts of transplant recipients with dilated (n=9) or ischemic (n=7) cardiomyopathy. The single-channel recording technique was used (70 mmol/L Ba2+). Peak average currents were significantly enhanced in heart failure (38.2+/-9.3 fA) versus nonfailing control hearts (13.2+/-4.5 fA, P=0.02) because of an elevation of channel availability (55.9+/-6.7% versus 26.4+/-5.3%, P=0.001) and open probability within active sweeps (7.36+/-1.51% versus 3.18+/-1.33%, P=0.04). These differences closely resembled the effects of a cAMP-dependent stimulation with 8-Br-cAMP (n= 11). Kinetic analysis of the slow gating shows that channels from failing hearts remain available for a longer time, suggesting a defect in the dephosphorylation. Indeed, the phosphatase inhibitor okadaic acid was unable to stimulate channel activity in myocytes from failing hearts (n=5). Expression of calcium channel subunits was measured by Northern blot analysis. Expression of alpha1c- and beta-subunits was unaltered. Whole-cell current measurements did not reveal an increase of current density in heart failure. CONCLUSIONS: Individual L-type calcium channels are fundamentally affected in severe human heart failure. This is probably important for the impairment of cardiac excitation-contraction coupling.

Single-channel properties of L-type calcium channels from failing human ventricle.

OBJECTIVE: The aim of our study was to analyse the single-channel properties of L-type calcium channels from failing human heart and to compare them to the respective animal data. Furthermore, we intended to evaluate the feasibility of future single-channel studies on the role of calcium channels in the pathophysiology of heart failure. METHODS: Single L-type calcium channels were recorded in ventricular myocytes from explanted failing human heart, using the cell-attached configuration of the patch-clamp technique. RESULTS: One or more successful registrations of calcium channels could be obtained in 11 of 19 cell isolations. Determination of single-channel conductance yielded a mean value of 16.6 +/- 1.2 pS (70 mM Ba2+ as the charge carrier) under control conditions and 23.7 +/- 2.8 pS in presence of the calcium-channel agonist FPL 64176. The rapid gating process could be described by a C<-->C<-->O gating scheme. Slow gating analysis revealed a highly significant clustering of active and non-active sweeps. CONCLUSION: Single-channel measurements of L-type calcium channels in human failing ventricle are feasible and reproducible despite the varying patient characteristics. Their channel properties are qualitatively comparable to those found in other mammals. Whether there are quantitative differences due to the underlying heart failure can be elucidated in further studies.

Stereoselectivity of Ca2+ channel block by dihydropyridines: no modulation by the voltage protocol.

The L-type Ca2+ current inhibition by the enantiomers of the dihydropyridine niguldipine was investigated at various holding potentials (-40 to -120 mV) and stimulus frequencies (0.1-1 Hz), using guinea-pig ventricular myocytes. Block of whole-cell current is both voltage- and concentration-dependent. (S)-Niguldipine is more potent than its (R)-enantiomer. However, the extent of enantioselectivity is rather small (< or = x 4.4). Importantly, this value does not increase when stimulus conditions favour the inactivated channel state, although this leads to more potent block. This is in contrast to our expectation based on modulated receptor hypothesis, and to the high enantioselectivity of niguldipine binding found in guinea-pig heart membranes (x 40). We conclude that the common modulated receptor hypothesis had to be refined to explain the effects of niguldipine enantiomers.