Effects of verapamil slow release plus trandolapril combination therapy on essential hypertension

BACKGROUND

Fixed-dose combination antihypertensive therapy has been recommended for patients with essential hypertension who are unresponsive to monotherapy or as a first-line treatment.

OBJECTIVE

We investigated the effects of a fixed-dose combination of the phenylalkylamine-type calcium channel blocker verapamil slow release (SR)plus the angiotensin-converting enzyme inhibitor trandolapril on blood pressure (BP), serum lipid profile, urinary albumin excretion (UAE), left ventricular mass (LVM), and LVM index (LVMI), as well as the adverse events associated with this treatment.

METHODS

Patients aged 30 to 65 years with mild to moderate essential hypertension were included in the study. All of the patients received capsules containing combination treatment with verapamil SR 180 mg plus trandolapril 2 mg orally, daily for 12 weeks. Mean arterial pressure (MAP), systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) were measured at baseline and at 4, 8, and 12 weeks of treatment. Serum lipid profile, UAE, LVM, LVMI, and body mass index (BMI) were determined at baseline and at the end of the study period. All patients underwent electrocardiography and echocardiography at baseline and week 12. The primary end point of the study was to achieve an SBP/DBP ≤140/≤90 mm Hg (ie, normotensive) during week 12. All adverse events were assessed as mild, moderate, or severe at each visit. According to the response rate at week 12, patients were divided into 2 groups: those who became normotensive (responders) or those who remained hypertensive (SBP/DBP >140/>90 mm Hg; nonresponders).

RESULTS

Forty-one patients (29 women, 12 men; mean [SD] age, 47.7 [7.8] years; mean [SD] BMI, 29.4 [3.5] kg/m(2)) were enrolled. The median durationof hypertension prior to enrollment was 5 months. Mean MAP, SBP, DBP, UAE, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), LDL-C/highdensity lipoprotein cholesterol (HDL-C) ratio, LVM, LVMI, and BMI decreased significantly after 12 weeks of combination treatment; HR and triglyceride level did not change significantly. Treatment-related adverse events occurred in 31.7% of patients, and none were severe or caused any patient to withdraw from the study. The most common adverse events were cough, constipation, headache, and dryness in the throat. Microalbuminuria, which may be a marker of endothelial dysfunction, was found in 7 (17.1%) patients at baseline and regressed significantly after 12 weeks.

CONCLUSIONS

In this study population, the fixed-dose combination of verapamil-trandolapril was an effective and well-tolerated antihypertensive therapy. This combination significantly reduced MAP, BP, TC, LDL-C, LDL-C/HDL-C ratio, UAE, LVM, and LVMI. Also, microalbuminuria decreased after this treatment. Verapamil-trandolapril may be useful in preventing microalbuminuria and left ventricular hypertrophy in patients with essential hypertension.

A multi-site, two-phase, Prescription Opioid Addiction Treatment Study (POATS): rationale, design, and methodology

The National Institute on Drug Abuse Clinical Trials Network launched the Prescription Opioid Addiction Treatment Study (POATS) in response to rising rates of prescription opioid dependence and gaps in understanding the optimal course of treatment for this population. POATS employed a multi-site, two-phase adaptive, sequential treatment design to approximate clinical practice. The study took place at 10 community treatment programs around the United States. Participants included men and women age > or =18 who met Diagnostic and Statistical Manual, 4th Edition criteria for dependence upon prescription opioids, with physiologic features; those with a prominent history of heroin use (according to pre-specified criteria) were excluded. All participants received buprenorphine/naloxone (bup/nx). Phase 1 consisted of 4 weeks of bup/nx treatment, including a 14-day dose taper, with 8 weeks of follow-up. Phase 1 participants were monitored for treatment response during these 12 weeks. Those who relapsed to opioid use, as defined by pre-specified criteria, were invited to enter Phase 2; Phase 2 consisted of 12 weeks of bup/nx stabilization treatment, followed by a 4-week taper and 8 weeks of post-treatment follow-up. Participants were randomized at the beginning of Phase 1 to receive bup/nx, paired with either Standard Medical Management (SMM) or Enhanced Medical Management (EMM; defined as SMM plus individual drug counseling). Eligible participants entering Phase 2 were re-randomized to either EMM or SMM. POATS was developed to determine what benefit, if any, EMM offers over SMM in short-term and longer-term treatment paradigm. This paper describes the rationale and design of the study.

Clinical Pharmacology of Antihypertensive Therapy

Adequate control of blood pressure poses challenges for hypertensive patients and their physicians. Success rates of greater than 80% in reducing blood pressure to target values among high-risk hypertensive patients reported by several recent clinical trials argue that effective medications currently are available. Yet, only 34% of hypertensive patients in the United States are at their goal blood pressure according to the most recent national survey. Rational selection of antihypertensive drugs that target both the patient's blood pressure and comorbid conditions coupled with more frequent use of low-dose drug combinations that have additive efficacy and low adverse-effect profiles could improve significantly US blood pressure control rates and have a positive impact on hypertension-related cardiovascular and renal mortality and morbidity. This article reviews the pharmacokinetic and pharmacodynamic principles that underlie the actions of drugs in each of the classes of antihypertensive agents when used alone and in combination, provides practical pharmacologic information about the drugs most frequently prescribed for treatment of hypertension in the outpatient setting, and summarizes the current data influencing the selection of drugs that might be used most effectively in combination for the majority of hypertensive patients whose blood pressures are not controlled adequately by single-drug therapy.

Hypertension guidelines, meta-analyses and clinical trials: do we assume too much?

Given fundamental differences in the recommendations in guidelines from major national and international committees, we cannot rely on them unquestioningly. Different antihypertensive agents are known to have differing effects according to age and race. Exchanging (rather than following guideline recommendations of adding to) an ineffective first-line antihypertensive drug can result in control of hypertension with monotherapy. Conclusions about a preferable first-line antihypertensive agent are limited by trial protocols with varying drug doses and questionable drug combinations. Guidelines are often based on meta-analyses of drugs of a particular class, which could ignore important differences between drugs within a class. Trials of 3-5 years cannot determine the long-term effects of drugs which patients often take for decades.

Creating a combination antihypertensive regimen: what does the research show?

Major randomized clinical trials have demonstrated unquestionable clinical benefits of lowering blood pressure without establishing superiority of any specific antihypertensive medication. Most notably, these trials have indicated that a majority of patients with hypertension will require more than one drug to control blood pressure. The recognition that many patients with hypertension should receive a combination of two agents as initial therapy is reflected in current hypertension guidelines, including the recently published consensus statement by the Hypertension in African Americans Working Group (HAAWG) and the seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7). In addition, there are some data that suggest that combination therapy may afford greater cardioprotection compared to monotherapy. For example, findings from A Lotrel Evaluation of Hypertensive Patients with Arterial Stiffness and Left Ventricular Hypertrophy (ALERT) indicated that low-dose combined angiotensin-converting enzyme inhibitor and calcium channel blocker antihypertensive treatment improved measures of cardiovascular structure and function compared with high-dose monotherapy with either component. Intuitive clinical wisdom suggests that some combinations of antihypertensive agents may provide enhanced clinical benefits; however, clinical trial data have not established optimal combination regimens. Thus, a challenging task for investigators is to determine which combination therapy regimens will provide the greatest cardiovascular benefits for patients with hypertension. A trial that is now in progress, Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH), directly compares cardiovascular mortality and morbidity rates for two preselected, fixed-dose combination therapies.

A review of olmesartan medoxomil monotherapy: antihypertensive efficacy similar to that of other angiotensin II receptor blocker/hydrochlorothiazide combinations?

Angiotensin II receptor blockers (ARBs) have been available in the United States since 1995. These agents have demonstrated antihypertensive efficacy at least similar to that of agents from other antihypertensive classes. Recent large-scale, randomized, controlled clinical trials have demonstrated that ARBs offer cardiovascular and renal protective benefits independent of their effects on systemic blood pressure (BP), which make them valuable as first-line antihypertensive agents, especially in high-risk patients. However, as is the case with other antihypertensive classes, monotherapy with the first-available ARBs (losartan potassium, valsartan, and irbesartan) may not provide sufficient BP reduction to achieve currently recommended BP goals in many patients. The diuretic hydrochlorothiazide is frequently added to enhance the ability of ARBs to lower BP. Several head-to-head comparison studies have shown differences in antihypertensive efficacy among the available ARBs. The newest ARB, olmesartan medoxomil, was recently compared with losartan potassium, irbesartan, and valsartan in a prospective, head-to-head, randomized trial. In this study, olmesartan medoxomil demonstrated a significantly greater reduction in diastolic BP, the primary end point, compared with the other three ARBs. Further, a review of the absolute reductions in diastolic BP achieved with olmesartan medoxomil monotherapy appears comparable to that of previously available ARBs when they are used in combination with hydrochlorothiazide. These comparisons may have important clinical implications regarding the optimal choice of first-line antihypertensive therapy.

Antihypertensive pharmacogenetics: getting the right drug into the right patient

Pharmacogenetic investigation seeks to identify genetic factors that contribute to interpatient and interdrug variation in responses to antihypertensive drug therapy. Classical studies have characterized single gene polymorphisms of drug metabolizing enzymes that are responsible for large interindividual differences in pharmacokinetic responses to several antihypertensive drugs. Progress is being made using candidate gene and genome scanning approaches to identify and characterize many additional genes influencing pharmacodynamic mechanisms that contribute to interindividual differences in responses to antihypertensive drug therapy. Knowledge of polymorphic variation in these genes will help to predict individual patients' blood pressure responses to antihypertensive drug therapy and may also provide new insights into molecular mechanisms responsible for elevation of blood pressure.

Potential cardioprotective effect of mibefradil in the long-term treatment of hypertension

During the last 2 decades, remarkable progress has been made in the treatment of hypertension with the discovery of new drugs lowering blood pressure by various mechanisms, e.g. calcium channel blockers, angiotensin-converting enzyme inhibitors and angiotensin II antagonists. These antihypertensive agents are now widely used as first-line therapy although there is still no definite proof that they have a cardioprotective effect and reduce the mortality rate in patients with coronary heart disease. Mibefradil is a new calcium antagonist with a novel mechanism of action since it is the only drug available so far able to block T channels. This compound might be particularly effective in preventing cardiac morbidity and mortality. It reduces heart rate when lowering blood pressure, has no negative inotropic effect, allows regression of cardiac hypertrophy and is effective in the treatment of angina. Mibefradil produces a sustained blood pressure reduction with a close to optimal trough:peak ratio. A major advantage of this novel compound is its excellent tolerability over the dose range recommended (50-100 mg/day). In particular, leg edema is seen clearly less often during mibefradil treatment than during therapy with dihydropyridines. Mibefradil has therefore an attractive profile in terms of both efficacy and safety and represents a promising first-line option to treat hypertensive patients.

The natriuretic effect of nifedipine gastrointestinal therapeutic system remains despite the presence of mild-to-moderate renal failure

BACKGROUND

Calcium channel blockers facilitate the renal excretion of sodium and this effect is maintained during chronic administration of these drugs. However, it is unknown whether this natriuretic effect remains despite the presence of a decreased renal function.

OBJECTIVE

To compare the natriuretic capacity of nifedipine gastrointestinal therapeutic system (GITS) and lisinopril in patients with mild-to-moderate chronic renal failure.

METHODS

An open-label, randomized, comparative study was conducted to compare the natriuretic capacity of nifedipine GITS and lisinopril in the presence of mild-to-moderate renal failure (creatinine clearance 30-80 ml/min). After a wash-out period of 4 weeks an intravenous saline infusion (30 ml/kg of body weight of isotonic saline in 4 h) was performed and repeated after 4 weeks of active therapy. Two sex- and age-matched groups of hypertensive patients (n = 25) were included in the study. Renal failure was diagnosed as secondary to nephrosclerosis in all the patients.

RESULTS

A significant increase in the renal capacity to excrete the sodium load was observed in patients receiving nifedipine GITS (n = 11) but not in those taking lisinopril (n = 13). Both drugs controlled blood pressure to a similar extent. No changes were observed in body weight, glomerular filtration rate and renal plasma flow (measured as inulin and paraaminohippurate clearances). A significant drop was observed in urinary albumin excretion after lisinopril, but not after nifedipine. Heart rate was higher in nifedipine group.

CONCLUSION

The natriuretic capacity of nifedipine GITS remains despite the presence of mild-to-moderate chronic renal failure. Such an effect takes place in the absence of changes in renal hemodynamics, suggesting that it is caused by a direct tubular effect.