Quantification of Hydrochlorothiazide and Ramipril/Ramiprilate in Blood Serum and Cerebrospinal Fluid: A Pharmacokinetic Assessment of Central Nervous System Adverse Effects.

BACKGROUND: A drug must reach the central nervous system (CNS) in order to directly cause CNS adverse effects (AEs). Our current study addressed the pharmacokinetic (PK) background of the assumption that CNS concentrations of hydrochlorothiazide (HCT) and ramiprilate may directly cause CNS AEs such as headache and drowsiness. METHODS: In neurological patients, paired serum and cerebrospinal fluid (CSF) samples were withdrawn simultaneously. Some of them were treated with HCT (n = 15, daily chronic doses 7.5-25 mg) or ramipril (n = 9, 2.5-10 mg). Total concentrations of HCT and ramiprilate were quantified in these samples. To this end, sensitive liquid chromatography/tandem mass spectrometry methods were developed. RESULTS: CSF reached 4.1% (interquartile ranges 2.5-5%) of total serum concentrations for HCT and 2.3% (1.7-5.7%) for ramiprilate, corresponding to about 11.3% and 5.5% of respective unbound serum concentrations. CONCLUSION: The PK/Pharmacodynamic characteristics of HCT and ramiprilate in the CNS are unknown. However, since the CSF levels of these agents, both free and bound, were much lower than the corresponding concentrations in serum, it is unlikely that the observed CNS AEs are mediated primarily via direct effects in the brain.

Assessment of glomerular filtration rate based on alterations of serum brain-derived neurotrophic factor in type 2 diabetic subjects treated with amlodipine/benazepril or valsartan/hydrochlorothiazide.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is associated with sympathetic activation. However, the effects of BDNF on diabetic nephropathy are unknown. The aim of this study was to assess the estimated glomerular filtration rates (eGFRs) and changes in serum BDNF levels in type 2 diabetic subjects treated with antihypertensive medications. METHODS: In this randomized, double-blind clinical trial, type 2 diabetic subjects with hypertension were assigned to either the benazepril/amlodipine or valsartan/hydrochlorothiazide treatment groups for a 16-week period. The post hoc analyses were based on increased or decreased serum BDNF levels. RESULTS: Of the 153 enrolled subjects, the changes in eGFR were significantly and inversely correlated with those in BDNF in the 76 subjects treated with valsartan/hydrochlorothiazide (r = -0.264, P = 0.021) but not in the 77 subjects treated with benazepril/amlodipine (r = -0.025, P = 0.862). The 45 subjects with increased BDNF following valsartan/hydrochlorothiazide treatment exhibited a significantly reduced eGFR (-8.8 ± 14.9 mL/min/1.73 m(2); P < 0.001). Multivariate regression analysis revealed that increased serum BDNF represents an independent factor for reduced eGFR (95% confidence interval between -0.887 and -0.076, P = 0.020). CONCLUSIONS: Increased serum BDNF is associated with reduced eGFR in type 2 diabetic subjects treated with valsartan/hydrochlorothiazide but not with amlodipine/benazepril.

Pharmacokinetic drug-drug interaction assessment between LCZ696, an angiotensin receptor neprilysin inhibitor, and hydrochlorothiazide, amlodipine, or carvedilol.

LCZ696 is a first-in-class angiotensin receptor neprilysin inhibitor in development for treatments of hypertension and heart failure indications. In 3 separate studies, pharmacokinetic drug-drug interactions (DDIs) potential was assessed when LCZ696 was coadministered with hydrochlorothiazide (HCTZ), amlodipine, or carvedilol. The studies used a open-label, single-sequence, 3-period, crossover design in healthy subjects. Blood samples were collected to determine the pharmacokinetic parameters of LCZ696 analytes (AHU377, LBQ657, and valsartan), HCTZ, amlodipine, or carvedilol (R[+]- and S[-]-carvedilol) for statistical analysis. When coadministered LCZ696 with HCTZ, the 90% CIs of the geometric mean ratios of AUCtau,ss of HCTZ and that of LBQ657 were within a 0.80-1.25 interval, whereas HCTZ Cmax,ss decreased by 26%, LBQ657 Cmax,ss increased by 19%, and the AUCtau,ss and Cmax,ss of valsartan increased by 14% and 16%, respectively. Pharmacokinetics of amlodipine, R(+)- and S(-)-carvedilol, or LBQ657 were not altered after coadministration of LCZ696 with amlodipine or carvedilol. Coadministration of LCZ696 400 mg once daily (qd) with HCTZ 25 mg qd, amlodipine 10 mg qd, or carvedilol 25 mg twice a day (bid) had no clinically relevant pharmacokinetic drug-drug interactions. LCZ696, HCTZ, amlodipine, and carvedilol were safe and well tolerated when given alone or concomitantly in the investigated studies.

Comparing clinical effectiveness and drug toxicity with hydrochlorothiazide and chlorthalidone using two potency ratios in a managed care population.

This study compared the clinical effectiveness and drug toxicity of chlorthalidone and hydrochlorothiazide. Electronic health records and claims data were used to identify patients initially prescribed chlorthalidone or hydrochlorothiazide. A total of 214 patients prescribed chlorthalidone 25 mg were matched with 428 patients prescribed hydrochlorothiazide 25 mg (1:1 potency ratio) and 214 patients prescribed hydrochlorothiazide 50 mg (1:2 potency ratio). Mean systolic blood pressure/diastolic blood pressure values at least 30 days after initial prescription were lower with chlorthalidone (132.2/74 mm Hg) compared with hydrochlorothiazide 25 mg (137.0/77.5 mm Hg) and hydrochlorothiazide 50 mg (138.6/78.5 mm Hg) (P<.05 for all comparisons). Goal systolic blood pressure/diastolic blood pressure values were achieved in a higher percentage of patients prescribed chlorthalidone (45.0%/78.3%) than with either hydrochlorothiazide 25 mg (32.1%/63.9%) or hydrochlorothiazide 50 mg (32.8%/68.9%) (P<.05 for all comparisons). Mean serum potassium was 3.94 mEq/L with chlorthalidone 25 mg, 4.13 mEq/L with hydrochlorothiazide 25 mg (P<.01 vs chlorthalidone), and 3.96 mEq/L with hydrochlorothiazide 50 mg. These findings indicate that chlorthalidone 25 mg is associated with a better antihypertensive response than hydrochlorothiazide 25 mg or 50 mg, without clinically significant differences in serum potassium.

An economic evaluation of antihypertensive therapies based on clinical trials.

OBJECTIVE: Hypertension is a major issue in public health, and the financial costs associated with hypertension continue to increase. Cost-effectiveness studies focusing on antihypertensive drug combinations, however, have been scarce. The cost-effectiveness ratios of the traditional treatment (hydrochlorothiazide and atenolol) and the current treatment (losartan and amlodipine) were evaluated in patients with grade 1 or 2 hypertension (HT1-2). For patients with grade 3 hypertension (HT3), a third drug was added to the treatment combinations: enalapril was added to the traditional treatment, and hydrochlorothiazide was added to the current treatment. METHODS: Hypertension treatment costs were estimated on the basis of the purchase prices of the antihypertensive medications, and effectiveness was measured as the reduction in systolic blood pressure and diastolic blood pressure (in mm Hg) at the end of a 12-month study period. RESULTS: When the purchase price of the brand-name medication was used to calculate the cost, the traditional treatment presented a lower cost-effectiveness ratio [US$/mm Hg] than the current treatment in the HT1-2 group. In the HT3 group, however, there was no difference in cost-effectiveness ratio between the traditional treatment and the current treatment. The cost-effectiveness ratio differences between the treatment regimens maintained the same pattern when the purchase price of the lower-cost medication was used. CONCLUSIONS: We conclude that the traditional treatment is more cost-effective (US$/mm Hg) than the current treatment in the HT1-2 group. There was no difference in cost-effectiveness between the traditional treatment and the current treatment for the HT3 group.

An economic evaluation of antihypertensive therapies based on clinical trials

OBJECTIVE: Hypertension is a major issue in public health, and the financial costs associated with hypertension continue to increase. Cost-effectiveness studies focusing on antihypertensive drug combinations, however, have been scarce. The cost-effectiveness ratios of the traditional treatment (hydrochlorothiazide and atenolol) and the current treatment (losartan and amlodipine) were evaluated in patients with grade 1 or 2 hypertension (HT1-2). For patients with grade 3 hypertension (HT3), a third drug was added to the treatment combinations: enalapril was added to the traditional treatment, and hydrochlorothiazide was added to the current treatment. METHODS: Hypertension treatment costs were estimated on the basis of the purchase prices of the antihypertensive medications, and effectiveness was measured as the reduction in systolic blood pressure and diastolic blood pressure (in mm Hg) at the end of a 12-month study period. RESULTS: When the purchase price of the brand-name medication was used to calculate the cost, the traditional treatment presented a lower cost-effectiveness ratio [US$/mm Hg] than the current treatment in the HT1-2 group. In the HT3 group, however, there was no difference in cost-effectiveness ratio between the traditional treatment and the current treatment. The cost-effectiveness ratio differences between the treatment regimens maintained the same pattern when the purchase price of the lower-cost medication was used. CONCLUSIONS: We conclude that the traditional treatment is more cost-effective (US$/mm Hg) than the current treatment in the HT1-2 group. There was no difference in cost-effectiveness between the traditional treatment and the current treatment for the HT3 group.

Valsartan plus hydrochlorothiazide: a review of its use since its introduction.

INTRODUCTION: This review focuses on the role of the fixed-dose combination (FDC) drug valsartan/hydrochlorothiazide (HCTZ) in the treatment of hypertension. Effective blood pressure control often is not achieved with monotherapy and, instead, requires combinations of drugs with different mechanisms of action to produce additive or synergistic effects. AREAS COVERED: FDC valsartan/HCTZ enhances not only efficacy for blood pressure control but also provides beneficial effects on target organs beyond that expected from arterial pressure reduction alone. Data describe key clinical trial experiences with the FDC, with particular attention to efficacy and tolerability. Literature searches of these various topics were conducted in January 2011. There is evidence of potential benefits with this combination associated with left ventricular hypertrophy, left ventricular dysfunction and renal disease. The FDC is an effective treatment for patients with hypertension and is superior to monotherapy than either drug alone. EXPERT OPINION: In addition to the benefits of each drug, valsartan/HCTZ's metabolic interactions reduce some of the negative effects of both compounds. With its increased simplicity, minimal side-effect profile and efficacy without a significant cost penalty, valsartan/HCTZ represents an excellent choice for antihypertensive therapy.

Recurrence of adverse drug reactions following inappropriate re-prescription: better documentation, availability of information and monitoring are needed.

Adverse drug reactions (ADRs) are a common, and often preventable, cause of hospital admission, especially in the elderly, and can occur during hospitalization. In this current opinion article, we present three cases of recurrence of a serious ADR due to re-prescription of a withdrawn medication that highlight the need for a system to prevent the undesirable re-prescription of medications withdrawn because of an ADR. In addition, we describe an electronic system that could help prevent undesirable re-prescription following an ADR. Such a system should document ADRs systematically at the patient level, make this information available to relevant healthcare providers and the patient, and flag re-prescription of the offending drug. The effectiveness and cost effectiveness of such a system would need to be determined.

Losartan/Hydrochlorothiazide: a review of its use in the treatment of hypertension and for stroke risk reduction in patients with hypertension and left ventricular hypertrophy.

Losartan/hydrochlorothiazide (HCTZ) [Hyzaar(R)] is a fixed-dose combination of the angiotensin II receptor antagonist (angiotensin receptor blocker [ARB]) losartan and the thiazide diuretic HCTZ. It is indicated for the treatment of hypertension (including as initial therapy in severe hypertension) and for stroke risk reduction in patients with hypertension and left ventricular hypertrophy (LVH). Losartan/HCTZ is an effective combination therapy, lowering blood pressure (BP) to a greater extent than losartan or HCTZ alone in patients with hypertension. Other ARB/HCTZ fixed-dose combinations generally lowered BP to a greater extent than losartan/HCTZ in patients with hypertension, although whether this translates into improvements in cardiovascular outcomes is not known. In the LIFE study, losartan-based therapy was associated with a lower incidence of cardiovascular morbidity and mortality than atenolol-based therapy, mainly as a result of a reduced risk of stroke; the incidence of new-onset diabetes mellitus was also lower with losartan-based therapy. Losartan/HCTZ is a well tolerated combination therapy. Thus, losartan/HCTZ remains an important option in the treatment of hypertension, as well as being indicated to reduce stroke risk in patients with hypertension and LVH.

Management of hypertension with fixed dose combinations of candesartan cilexetil and hydrochlorothiazide: patient perspectives and clinical utility.

Hypertension treatment and control is largely unsatisfactory when guideline-defined blood pressure goal achievement and maintenance are considered. Patient- and physician-related factors leading to non-adherence interfere in this respect with the efficacy, tolerability, and convenient use of pharmacological treatment options. Blockers of the renin-angiotensin system (RAS) are an important component of antihypertensive combination therapy. Thiazide-type diuretics are usually added to increase the blood pressure lowering efficacy. Fixed drug-drug combinations of both principles like candesartan/hydrochlorothiazide (HCTZ) are highly effective in lowering blood pressure while providing improved compliance, a good tolerability, and largely neutral metabolic profile. Comparative studies with losartan/HCTZ have consistently shown a higher clinical efficacy with the candesartan/HCTZ combination. Data on the reduction of cardiovascular endpoints with fixed dose combinations of antihypertensive drugs are however scarce, as are the data for candesartan/HCTZ. But many trials have tested candesartan versus a non-RAS blocking comparator based on a standard therapy including thiazide diuretics. The indications tested were heart failure and stroke and particular emphasis was put on elderly patients or those with diabetes. In patients with heart failure, for example, the fixed dose combination might be applied in patients in whom individual titration resulted in a dose of 32 mg candesartan and 25 mg HCTZ which can then be combined into one tablet to increase compliance with treatment. Also in patients with stroke the fixed dose combination might be used in patients in whom maintenance therapy with both components is considered. Taken together candesartan/HCTZ assist both physicians and patients in achieving long-term blood pressure goal achievement and maintenance.

High prevalence of orthostatic hypotension and its correlation with potentially causative medications among elderly veterans.

BACKGROUND: Orthostatic hypotension (OH) is defined as a reduction of systolic blood pressure of at least 20 mmHg, or diastolic blood pressure of at least 10 mmHg from a sitting to a standing position. It is a common physical finding among older adults and associated with significant morbidity and mortality. Use of medications that have the potential to induce OH, particularly concomitant use of several of such medications, is a major factor for the development of OH. OBJECTIVES: To describe the prevalence of symptomatic and asymptomatic OH in veterans aged 75 years and older attending a geriatric clinic, and to assess the association between OH and the number of potentially causative medications used. METHODS: Charts of all patients who attended a VA geriatric clinic (Michael E. DeBakey VA Medical Center) during the period of 1 June 2002 to 1 June 2003 were reviewed retrospectively for (i) the use of potentially causative medications, i.e. medications that were reported to cause OH in at least 1% of the general population and that were available in the VA formulary, (ii) the presence or absence of OH, and (iii) the presence or absence of symptomatic OH. Patients with primary autonomic dysfunction, Parkinson's disease, and patients who were unable to stand, or who had no assessment for both sitting and standing blood pressure for other reasons were excluded. RESULTS: A total of 505 individual patients attended the clinic during the study period, and 342 patients fit the inclusion criteria. About 189 of these patients (55%) had OH. Among patients with OH, 61 patients (33%) were symptomatic, including 52 patients who had falls. The prevalence of OH in patients receiving zero, one, two, and three or more potentially causative medications was 35, 58, 60 and 65% respectively. Receiving hydrochlorothiazide was associated with the highest prevalence of OH (65%), followed by receiving lisinopril (60%), trazodone (58%), furosemide (56%) and terazosin (54%). CONCLUSION: The prevalence of OH is very high in older veterans and significantly related to the number of concurrent causative medications used. Providers should be educated to reduce the amount of potentially causative medications in the elderly and better assess patients in which use of such medications is necessary to avoid symptomatic OH.

Assessment of efficacy, safety and tolerability of fixed dose combination of telmisartan 40mg and hydrochlorothiazide 12.5mg in adult Indian patients with mild to moderate hypertension.

The objective of the study was to assess the efficacy, safety and tolerability of a fixed dose combination of telmisartan 40 mg and hydrochlorothiazide 12.5 mg in adult Indian patients with mild to moderate hypertension. A prospective, multicentric, open-label, non-comparative, phase IV study was conducted. A total of 353 patients of either sex, between 18- 65 years of age with supine blood pressure (BP) levels of systolic BP (SBP) of 140-200 mmHg and diastolic BP (DBP) of 95-114 mmHg were included. After a placebo run-in period of 2 weeks, each patient received a fixed dose combination of telmisartan/hydrochlorothiazide (40mg/12.5mg) once daily, for 8 weeks. Supine BP was assessed at the end of every 2 weeks. Tolerability and safety were assessed by physical examination, laboratory parameters and evaluation of adverse events. A total of 339 patients completed the study with 14 drop-out cases because of loss to follow-up. There was a significant fall (p<0.05) in both the SBP and DBP starting from the second week as compared to the baseline. Mean SBP had a significant reduction of 23.55 mmHg (15.0%) and 27.79 mmHg (18%) at the end of 6th and 8th week respectively, compared to baseline values. Mean DBP had also had a significant reduction of 12.51 mmHg (12.6%) and 15.17 mmHg (15.3%) at the end of 6th and 8th week respectively, compared to baseline values. This combination was well tolerated with only 3.9% of the total cases reporting mild adverse events like fatigue, dizziness, nausea, diarrhoea etc. The laboratory values were within normal limits. Fixed dose combination of telmisartan/hydrochlorothiazide (40 mg/12.5 mg) once daily has a significant therapeutic effect and a good tolerability profile in adult Indian patients with mild to moderate hypertension.

Low-dose thiazides in the treatment of hypertension: benefits and risks in perspective.

Diuretics in low doses are very effective agents for controlling hypertension either where used alone or in combination. They have a marked cardioprotective effect, are the best tolerated of any anti-hypertensives and are at the same time the least expensive.

Quinapril and hydrochlorothiazide combination for control of hypertension: assessment by factorial design. Quinapril Investigator Group.

A factorial design method was applied in this multicentre trial of the angiotensin-converting enzyme inhibitor quinapril hydrochloride (Accupril) in combination with the diuretic hydrochlorothiazide (HCTZ) to assess the additive effects of the combination versus monotherapy, to characterise the dose-response relationship of each drug in the presence of the other and to determine if quinapril would attenuate the hypokalemic effect of HCTZ. Following a two to four week placebo-baseline period, 460 qualifying patients with a DBP > or = 100 mmHg and < or = 115 mmHg were randomised to an eight week double-blind phase with one of 16 parallel treatments: placebo, one of three doses of quinapril monotherapy, one of three doses of HCTZ monotherapy or one of nine possible corresponding combinations of quinapril and HCTZ. Mean reductions in sitting SBP/DBP at trough with combination therapy ranged from 7.8 mmHg/7.2 mmHg to 19.6 mmHg/15.1 mmHg (n = 458). Results of the response surface analyses indicate that the effects of the two drugs were additive and that the maximum antihypertensive effect of quinapril in combination with HCTZ within the doses studied is achieved approximately at a dose of 26 mg quinapril and 25 mg HCTZ. The degree of attenuation of the hypokalemic effect of HCTZ was directly related to the dose of quinapril. At 40 mg quinapril, the HCTZ dose-related decreases of serum potassium were not apparent and overall hypokalemic effects were attenuated by quinapril. Thus, the combination of quinapril and HCTZ given once daily provided additive antihypertensive effects of predictable degrees and the addition of quinapril attenuated the hypokalemic effect of HCTZ.

An assessment of diltiazem and hydrochlorothiazide in hypertension. Application of factorial trial design to a multicenter clinical trial of combination therapy.

This multicenter, factorial-design trial assessed the safety and additive antihypertensive efficacy of a slow-release (SR) formulation of diltiazem hydrochloride given alone or in combination with hydrochlorothiazide for treatment of mild to moderate hypertension. After a 4- to 6-week placebo run-in period, 297 qualifying patients were randomized to receive placebo, 1 of 4 doses of diltiazem SR monotherapy, 1 of 3 doses of hydrochlorothiazide monotherapy, or 1 of 12 possible combinations of diltiazem SR and hydrochlorothiazide for 6 weeks. A dose-related reduction in blood pressure was demonstrated for each drug as monotherapy and for the two drugs in combination. Absolute blood pressures of patients who received combination therapy were lower by an overall mean of 3.0 mm Hg diastolic and 8.0 mm Hg systolic vs diltiazem SR used alone and 3.5 mm Hg diastolic and 4.0 mm Hg systolic vs hydrochlorothiazide used alone. At the largest doses used, 50% of patients achieved goal blood pressure while taking hydrochlorothiazide, 57% while taking diltiazem SR, and 75% while taking combination therapy. Combination therapy was well tolerated. This trial clearly demonstrates that diltiazem SR and hydrochlorothiazide have additive antihypertensive effects.

[Assessment of tolerability and antihypertensive efficacy of aceplus mite (captopril (CPT) 50 mg + hydrochlorothiazide (HCTZ) 15 mg): a double-blind study vs. HCTZ in diabetic hypertensive patients. A report on three treatments]. / Valutazione della sicurezza, tollerabilità ed efficacia anti-ipertensiva dell'aceplus mite [captopril (CPT) 50 mg + idroclorotiazide (HCTZ) 15 mg]: studio in doppio cieco vs. HCTZ in pazienti diabetici ipertesi. Rapporto a 3 mesi di trattamento.

Thirty hypertensive diabetic patients were randomly, double blindly, treated with Captopril (CPT) 50 mg + hydrochlorothiazide (HCTZ) 15 mg (No 19) or HCTZ 25 mg alone (No 11) for 3 months, to assess blood pressure control and some metabolic modifications. The results indicate that CPT + a low dose of HCTZ maintains the synergistic effect of the two drugs, minimizing the metabolic problems related to HCTZ in hypertensive diabetic patients.