Choosing the right ACE inhibitor. A guide to selection

The therapeutic potential of renin-angiotensin system inhibitors in the treatment of pancreatic cancer

Pancreatic cancer is among the most lethal malignancies with poor prognosis and patients become chemoresistant to current therapies, supporting further investigations to identify new therapeutic regimens in the treatment of this condition. Preclinical and clinical studies now appear to support the role of the renin-angiotensin system (RAS) in the regulation of tumor growth, angiogenesis, and metastasis in different malignancies including pancreatic cancer. These studies suggest that RAS blockers; Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs); could have anti-carcinogenic effects and improve clinical outcomes in the management of pancreatic cancer. Here we provided an overview of ACE inhibitors and ARBs as a potential therapeutic option in the treatment of pancreatic cancer.

Efficacy and safety of twice- vs once-daily dosing of lisinopril for hypertension

This retrospective cohort study compared administration of lisinopril twice daily and once daily for hypertension. Data were collected from an ambulatory electronic health record between 2011 and 2014. Patients previously receiving lisinopril 20 mg were placed into the once-daily cohort if changed to 40 mg once daily or into the twice-daily cohort if changed to 20 mg twice daily. Efficacy outcome measures were change in systolic blood pressure and diastolic blood pressure and achievement of blood pressure control (<140/90 mm Hg). Of 90 patients included (45 per cohort), the mean age was 61.8 years and 17.8% were black. Once- and twice-daily administrations were associated with blood pressure reductions of 6.2/1.5 mm Hg and 16.5/5.9 mm Hg, with a 10.2/4.3 mm Hg greater reduction with twice-daily administration (systolic blood pressure, P=.016; diastolic blood pressure, P=.068). Twice-daily lisinopril dosing was associated with greater systolic blood pressure reductions compared with the same total daily dose administered once daily.

Biowaiver Monographs for Immediate-Release Solid Oral Dosage Forms: Enalapril

Literature data relevant to the decision to allow a waiver of in vivo bioequivalence testing for the marketing authorization of immediate-release, solid oral dosage forms containing enalapril maleate are reviewed. Enalapril, a prodrug, is hydrolyzed by carboxylesterases to the active angiotensin-converting enzyme inhibitor enalaprilat. Enalapril as the maleate salt is shown to be highly soluble, but only 60%-70% of an orally administered dose of enalapril is absorbed from the gastrointestinal tract into the enterocytes. Consequently, enalapril maleate is a Biopharmaceutics Classification System class III substance. Because in situ conversion of the maleate salt to the sodium salt is sometimes used in production of the finished drug product, not every enalapril maleate-labeled finished product actually contains the maleate salt. Enalapril is not considered to have a narrow therapeutic index. With this background, a biowaiver-based approval procedure for new generic products or after major revisions to existing products is deemed acceptable, provided the in vitro dissolution of both test and reference preparation is very rapid (at least 85% within 15 min at pH 1.2, 4.5, and 6.8). Additionally, the test and reference product must contain the identical active drug ingredient.

Class effects and evidence-based medicine

Drugs grouped into a therapeutic class on the basis of a common mechanism of action often have considerably different pharmacodynamic and pharmacokinetic properties. Among angiotensin-converting enzyme (ACE) inhibitors, differences with potential clinical relevance include potency, whether the drug is an active compound or requires metabolic activation, lipophilicity, route(s) of elimination, and half-life. Large clinical trials have documented the clinical benefits of several ACE inhibitors in various patient populations, and many clinical effects of ACE inhibitors are likely to be the same. However, there are possible quantitative differences among ACE inhibitors that may alter the overall therapeutic benefits for specific patient populations and indications. Equipotency in terms of clinical efficacy is difficult to determine. Since the concept of "class effect" is a term of convenience that has no universally accepted definition and subsequently should not form the basis for the practice of evidence-based medicine, untested drugs of a "class" should be considered to be unproven drugs.

Three angiotensin-converting enzyme inhibitors from Rabdosia coetsa

The EtOAc extract of Rabdosia coetsa showed angiotensin-converting enzyme (ACE) inhibitory activity. Bioassay-guided isolation of this extract yielded ethyl caffeate (1), rosmarinic acid (2) and methyl rosmarinate (3), which inhibited ACE activity by 32.42%, 55.19% and 39.50% respectively, at the concentration of 10 microg/ml.

Tissue angiotensin-converting enzyme inhibitors: are they more effective than serum angiotensin-converting enzyme inhibitors?

Since their discovery in the 1980s, angiotensin-converting enzyme (ACE) inhibitors have been shown to decrease angiotensin formation, prevent breakdown of bradykinin, and may also act on peptides of the renin-angiotensin system. They are effective in reducing the risk of heart failure, myocardial infarction, and death from cardiovascular causes in patients with left ventricular systolic dysfunction or heart failure, and have been shown to reduce atherosclerotic complications in patients who have vascular disease without heart failure. They may preserve endothelial function and counteract initiation and progression of atherosclerosis. Broadly, ACE inhibitors can be divided into tissue specific or serum ACE inhibitors. Tissue-specific ACE inhibitors as a group are not superior to serum ACE inhibitors in the treatment of coronary artery disease. Pending direct comparator clinical trials between a tissue ACE inhibitor and a plasma ACE inhibitor, both ramipril and perindopril can be recommended for secondary risk prevention, based on the evidence.

Zofenopril versus Lisinopril in the Treatment of Essential Hypertension in Elderly Patients

BACKGROUND

Angiotensin-converting enzyme inhibitors have been proposed as first-choice drugs for antihypertensive therapy in elderly subjects because of their demonstrated efficacy and safety. However, no information is currently available on the use of zofenopril in elderly hypertensive patients.

OBJECTIVE

To assess the efficacy and safety of zofenopril (30 or 60mg once daily) compared with lisinopril (10 or 20mg once daily).

PATIENTS AND METHODS

Patients aged >/=65 years with mild to moderate essential hypertension (sitting diastolic blood pressure [DBP] >/=90mm Hg and </=110mm Hg) were included in the study. They were randomised to receive either zofenopril 30mg or lisinopril 10mg. Blood pressure and heart rate were measured at baseline and after 4 and 12 weeks of treatment. Patients underwent electrocardiography and evaluation of laboratory parameters at baseline and after 12 weeks. Ambulatory blood pressure monitoring (ABPM) was also performed at baseline and after 12 weeks. After 4 weeks drug doses were doubled in patients whose sitting DBP was >/=90mm Hg. The primary endpoint was to achieve sitting DBP values <90mm Hg or a reduction of sitting DBP >10mm Hg after 12 weeks of treatment.

RESULTS

181 patients were randomised to treatment and 164 patients completed the study. Thirty-three patients were included in the analysis of 24-hour blood pressure monitoring. The percentage of patients with normalised sitting DBP (<90mm Hg) and the rate of treatment responders (reduction of sitting DBP >/=10mm Hg) were not significantly different between the two treatment groups (normalised: zofenopril 81.3% vs lisinopril 76.7%; responders: zofenopril 74.7% vs lisinopril 77.8%). At the end of the treatment sitting DBP was not significantly different between the two treatment groups (zofenopril 82.2 +/- 6.6mm Hg vs lisinopril 82.0 +/- 7.8mm Hg). Eight percent of patients experienced adverse events in the zofenopril group and 9% in the lisinopril group. A small percentage of adverse events (4%) was related to treatment and reported in the zofenopril group.

CONCLUSIONS

In elderly hypertensive patients, treatment with zofenopril was effective and well tolerated. Efficacy and safety were comparable with those of lisinopril.

Knowing When to Play the Ace: The Use and Under Use of Ace Inhibitors in Primary Practice

The role of angiotensin-converting enzyme (ACE) inhibitors has expanded beyond the original indication of hypertension. Landmark studies and practice guidelines recommend the use of ACE inhibitors in patients with heart failure, post-myocardial infarction, and post-cerebrovascular accident to decrease morbidity and mortality. However, despite a sizable amount of literature and presence in treatment guidelines, this class of medications has been traditionally underused in the primary care setting. It is for this reason that pharmacists should play a more active role in increasing appropriate ACE inhibitor usage through interventions. Second, the idea that ACE inhibitors display a “class effect” is often used to justify interchange from one particular medication to another. However, there are structural differences and pharmacokinetic nuances that should not be understated. The objective of this article is to outline uses of ACE inhibitors beyond hypertension, discuss the under use of this class despite existing literature, and touch on the idea of class effect among ACE inhibitors.

Pharmacogenetics of Antihypertensive Drug Responses

The blood pressure (BP) response to any single antihypertensive drug is characterized by marked interindividual variation, and the known predictors of response are of limited value in identifying the optimum drug for an individual patient. Analysis of genetic variation has the potential to improve our understanding of determinants of antihypertensive drug response in order to individualize drug selection. Genetic variation can influence both pharmacokinetic and pharmacodynamic mechanisms underlying variation in drug response. Classic pharmacogenetic investigations have identified variations in single genes that have a large effect on antihypertensive drug metabolism and are inherited in a Mendelian fashion. These include a polymorphism in the CYP2D6 gene, encoding a cytochrome p450 family member involved in phase I drug metabolism, and polymorphisms in genes encoding enzymes involved in phase II drug metabolism, including N-acetyltransferase (NAT2), catechol-O-methyltransferase (COMT), and phenol sulfotransferase (P-PST, SULT1A1). Although these polymorphisms have major effects on the pharmacokinetic profiles of both commonly used antihypertensive drugs such as metoprolol (CYP2D6), and lesser used drugs such as hydralazine (NAT2), methyldopa (COMT), and minoxidil (SULT1A1), they have not been shown to influence variation in the antihypertensive effect of these drugs at conventional doses. Interest is now focused on identifying genetic polymorphisms that influence the pharmacodynamic determinants of antihypertensive response. Using a candidate gene approach, such polymorphisms have been identified in genes encoding alpha-adducin (ADD1), subunits of G-proteins (GNB3 and GNAS1), the beta(1)-adrenergic receptor (ADRB1), endothelial nitric oxide synthase (NOS3), and components of the renin-angiotensin-aldosterone system (angiotensinogen [AGT], angiotensin converting enzyme [ACE], the angiotensin type I receptor [AGTR1], and aldosterone synthase [CYP11B2]). These polymorphisms have been shown to influence the BP response to diuretics (ADD1, GNB3, NOS3, and ACE), beta-blockers (GNAS1 and ADRB1), ACE inhibitors (AGT, ACE, and AGTR1), angiotensin receptor blockers (ACE and CYP11B2), and clonidine (GNB3).An emerging consensus from these studies is that single gene effects on antihypertensive drug responses are small, and even the combined effects of all presently known polymorphisms do not account for enough variation in response to be clinically useful. New genome-wide scanning techniques may lead to the identification of genes previously unsuspected of influencing drug response. Additional requirements for pharmacogenetic approaches to become clinically useful are the characterization of the effects of haplotypes and multi-locus genotypes on drug response, and consideration of gene-by-environment interactions. Such studies will require huge sample sizes and novel statistical methods, but the theoretical and technical framework is in place to make this possible.

Can angiotensin-converting enzyme inhibitors reverse atherosclerosis?

Angiotensin II, a potent vasoconstrictor, is mainly present in the vascular endothelium. Multiple studies have confirmed that angiotensin-converting enzyme (ACE) inhibitors, which block the formation of angiotensin II, lower blood pressure and also improve heart failure. These agents not only have beneficial hemodynamic effects but also bestow additional benefits on vascular function and prevent clinical cardiovascular events in patients at risk for coronary artery disease. These latter benefits may represent effects of ACE inhibitors on local endocrine pathways, inflammatory processes, and atherosclerosis taking place within the arterial wall. Current evidence suggests that, although ACE inhibitors may not substantially reverse atherosclerotic plaque already present, they may slow the progression of such atherosclerotic lesions. In addition, by modulating inflammatory pathways within and adjacent to the atherosclerotic lesion, they may stabilize an unstable plaque and therefore decrease the risk of plaque rupture and its complications.

Effect of low-dose perindopril/indapamide on albuminuria in diabetes: preterax in albuminuria regression: PREMIER

Microalbuminuria in diabetes is a risk factor for early death and an indicator for aggressive blood pressure (BP) lowering. We compared a combination of 2 mg perindopril/0.625 mg indapamide with enalapril monotherapy on albumin excretion rate (AER) in patients with type 2 diabetes, albuminuria, and hypertension in a 12-month, randomized, double-blind, parallel-group international multicenter study. Four hundred eighty-one patients with type 2 diabetes and hypertension (systolic BP > or =140 mm Hg, <180 mm Hg, diastolic BP <110 mm Hg) were randomly assigned (age 59+/-9 years, 77% previously treated for hypertension). Results from 457 patients (intention-to-treat analysis) were available. After a 4-week placebo period, patients with albuminuria >20 and <500 microg/min were randomly assigned to a combination of 2 mg perindopril/0.625 mg indapamide or to 10 mg daily enalapril. After week 12, doses were adjusted on the basis of BP to a maximum of 8 mg perindopril/2.5 mg indapamide or 40 mg enalapril. The main outcome measures were overnight AER and supine BP. Both treatments reduced BP. Perindopril/indapamide treatment resulted in a statistically significant higher fall in both BP (-3.0 [95% CI -5.6, -0.4], P=0.012; systolic BP -1.5 [95% CI -3.0, -0.1] diastolic BP P=0.019) and AER -42% (95% CI -50%, -33%) versus -27% (95% CI -37%, -16%) with enalapril. The greater AER reduction remained significant after adjustment for mean BP. Adverse events were similar in the 2 groups. Thus, first-line treatment with low-dose combination perindopril/indapamide induces a greater decrease in albuminuria than enalapril, partially independent of BP reduction. A BP-independent effect of the combination may increase renal protection.

Building and evaluation of a structured representation of pharmacokinetics information presented in SPCs: from existing conceptual views of pharmacokinetics associated with natural language processing to object-oriented design

OBJECTIVE

Develop a detailed representation of pharmacokinetics (PK), derived from the information in Summaries of Product Characteristics (SPCs), for use in computerized systems to help practitioners in pharmaco-therapeutic reasoning.

METHODS

Available knowledge about PK was studied to identify main PK concepts and organize them in a preliminary generic model. The information from 1950 PK SPC-texts in the French language was studied using a morpho-syntactic analyzer. It produced a list of candidate terms (CTs) from which those describing main PK concepts were selected. The contexts in which they occurred were explored to discover co-occurring CTs. The regrouping according to CT semantic types led to a detailed object-oriented model of PK. The model was evaluated. A random sample of 100 PK texts structured according to the model was judged for completeness and semantic accuracy by 8 experts who were blinded to other experts' responses.

RESULTS

The PK text file contained about 300000 words, and the morpho-syntactic analysis extracted 17520 different CTs. The context of 592 CTs was studied and used to deduce the PK model. It consists of four entities: the information about the real PK process, the experimental protocol, the mathematical modeling, and the influence of factors causing variation. Experts judged that the PK model represented the information in 100 sample PK texts completely in 89% of cases and nearly completely in the other 11%. There was no distortion of meaning in 98% of cases and little distortion in the remainder.

CONCLUSION

The PK model seems to be applicable to all SPCs and can be used to retranscribe legal information from PK sections of SPCs into structured databases.

Drugs targeting the renin-angiotensin-aldosterone system

Effective antihypertensive therapy has made a major contribution to the reductions in the morbidity and mortality of cardiovascular disease that have been achieved since the 1960s. However, blood-pressure control with conventional drugs has not succeeded in reducing cardiovascular disease risks to levels seen in normotensive persons. Drugs that inhibit or antagonize components of the renin-angiotensin-aldosterone system are addressing this deficiency by targeting both blood pressure and related structural and functional abnormalities of the heart and blood vessels, thus preventing target-organ damage and related cardiovascular events.

Perindopril: an updated review of its use in hypertension

Perindopril erbumine (perindopril) is a prodrug ester of perindoprilat, an angiotensin converting enzyme (ACE) inhibitor. Perindopril 4 to 8 mg once daily significantly reduces supine systolic blood pressure (SBP) and diastolic blood pressure (DBP) from baseline values in hypertensive patients. These reductions are maintained for at least 24 hours, as evidenced by trough/peak ratios of >50%. Vascular abnormalities associated with hypertension were improved or normalised during perindopril treatment. Perindopril 4 to 8 mg once daily significantly decreased carotid-femoral aortic pulse wave velocity (PWV), improved arterial compliance, reduced left ventricular mass index and, in patients with recent cerebral ischaemia and/or stroke, preserved cerebral blood flow despite significantly reducing SBP and DBP. Further research is needed to establish the significance of promising results showing that reductions in aortic PWV were associated with reduced mortality in patients with end-stage renal failure, a third of whom received perindopril. Response rates (numbers of patients with supine DBP < or = 90 mm Hg) were significantly higher with perindopril 4 to 8 mg once daily (67 to 80%) than with captopril 25 to 50 mg twice daily (44 to 57%) in 3 randomised double-blind trials. In other clinical trials, the antihypertensive effects of perindopril were similar to those of other ACE inhibitors (including enalapril) and calcium-channel antagonists. Combination treatment with perindopril and an antihypertensive agent from another treatment class provided additional benefits, either as first-line treatment or in patients failing to respond to monotherapy. Perindopril monotherapy was also effective in the elderly and in patients with hypertension and concomitant disease. Perindopril has a similar adverse event profile to that of other ACE inhibitors; cough is the most common event reported during treatment, and is also the most common adverse event responsible for treatment withdrawal.

CONCLUSIONS

Perindopril is a well tolerated ACE inhibitor that is significantly better than captopril (in terms of response rates) in the treatment of hypertension, and as effective as other ACE inhibitors. Perindopril appears to reverse some of the vascular abnormalities associated with hypertension, including arterial stiffness and left ventricular hypertrophy, although further research is needed to confirm promising results regarding its ability to decrease associated cardiovascular morbidity and mortality. Results from ongoing studies will help confirm the place of perindopril in the treatment of hypertension; currently, it is an effective and well tolerated treatment for patients with mild to moderate essential hypertension.

The Heart Outcomes Prevention Evaluation study: angiotensin-converting enzyme inhibitors: are their benefits a class effect or do individual agents differ?

The Heart Outcomes Prevention Evaluation study was a landmark study employing the angiotensin-converting enzyme inhibitor ramipril in a patient population pre-destined for vascular events. This study found that a 10 mg dose of ramipril in comparison with placebo reduced the incidence of death, myocardial infarction, stroke, and death from cardiovascular causes by 22%. This improvement in outcome was viewed as a direct consequence of ramipril, although the fact that blood pressure was reduced with ramipril has cast some considerable doubt on this supposition. Whether the observed findings in this study are a 'class effect' for all angiotensin-converting enzyme inhibitors is unclear. To its credit, ramipril is the first angiotensin-converting enzyme inhibitor shown to prevent ischemic events in high-risk patients without discernible left ventricular dysfunction. Other similar trials are underway, which are studying similar populations to those included in this landmark study and should resolve the question of whether the cardioprotective effects of angiotensin-converting enzyme inhibitors are a 'class effect'.

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.

Pharmacologic Regulation of the Renin—Angiotensin System: Physiologic and Pathologic Effects

Objective:

To review the physiologic and pathologic roles of the renin-angiotensin system in maintaining blood pressure, glomerular filtration rate, and myocardial tissue growth. The pharmacologic regulations of the pathologic effects of the renin-angiotensin system are emphasized, with a comparison between angiotensin-converting enzyme (ACE) inhibitors and angiotensin1receptor (AT1) antagonists.

Data Sources:

English-language basic science, clinical studies, and review articles were identified using MEDLINE, IOWA, and a manual search from January 1966 through September 1999. References were also obtained from the reference section of relevant published articles.

Study Selection and Data Extraction:

All articles identified were evaluated for possible inclusion in this review. Evaluative and comparative data from basic science and controlled clinical studies were reviewed.

Data Synthesis:

The renin-angiotensin system has a plethora of physiologic and pathologic roles in the regulation of blood pressure, renal function, and cell growth. The cellular mechanisms involved in eliciting the responses to the renin-angiotensin system are discussed in detail, with an emphasis on the pharmacologic regulation of the cellular responses. The role of angiotensin II in maintaining blood pressure, glomerular filtration rate, and in regulating myocardial cell growth secondary to myocardial infarction or as a complication of congestive heart failure are all reviewed. The ACE inhibitors and AT1antagonists have comparable pharmacologic effects that can influence their therapeutic application. The ACE inhibitors and AT, antagonists are compared regarding clinically and experimentally observed differences that may affect their therapeutic application.

Conclusions:

The physiologic and pathologic roles of the renin-angiotensin system make the ACE inhibitors and AT1antagonists ideal candidates in treating many conditions. Presently, few studies have been conducted that directly compare ACE inhibitors and AT, antagonists. An understanding of the basic underlying pharmacologic principles is essential when attempting to apply the scientific and clinical information of the ACE inhibitors and AT1antagonists with the intention of extrapolating to therapeutic utility.

Coumarin-Ser-Asp-Lys-Pro-OH, a fluorescent substrate for determination of angiotensin-converting enzyme activity via high-performance liquid chromatography

N-Acetyl-Ser-Asp-Lys-Pro-OH (AcSDKP-OH), a negative regulator of hematopoietic stem cell proliferation, is shown to be a physiological substrate of angiotensin I-converting enzyme (ACE), a zinc-dipeptidyl carboxypeptidase, involved in cardiovascular homeostasis. Recently, a study carried out on captopril-treated volunteers revealed that the kinetics of [3H]AcSDKP-OH hydrolysis in vitro in the plasma of donors correlates closely to the plasmatic ratio angiotensin II/angiotensin I, which characterized the conversion activity of ACE. This prompted us to design a fluorescent substrate, 2-[7-(dimethylamino)-2-oxo-2H-chromen-4-yl]acetyl-SDKP-OH, or coumarin-SDKP-OH, which could be an alternative to the radiolabeled analogue used in that study, allowing an easier and more rapid determination of enzyme activity. We report here the synthesis and the determination of the kinetics constants of this fluorescent derivative compared with those of [3H]AcSDKP-OH with human plasma ACE (133 and 125 microM, respectively), which are in the same range as those of the physiological substrate angiotensin I. Furthermore, the hydrolysis of the fluorescent substrate shows the same sensitivity toward chloride concentration as the natural substrate, demonstrating its specificity for N-domain hydrolysis. This fluorescent derivative was used to develop a sensitive assay for the determination of ACE activity in human plasma.

Evaluation of high through-to-peak ratio of perindopril in SHR

The present study was designed to evaluate trough-to-peak ratio (T/P) of ACE inhibitors in spontaneously hypertensive rats (SHR) by a continuous monitoring of ambulatory blood pressure for 24 hours with a biotelemetric system. Blood pressure was recorded uninterruptedly with a battery-operated transmitter connected to a sensor catheter. Perindopril (3 mg/kg), trandolapril (1 mg/kg), quinapril (10 mg/kg) and enalapril (6 mg/kg) were given once a day for 7 days. On the first day of the treatment these ACE inhibitors equally decreased blood pressure by 20 mmHg at each peak. The peak and trough blood pressure decreased steadily until day 4, and then they were constant until the end of experiment (day 7). T/P for each inhibitor also increased until day 4, and the ratios in systolic blood pressure at the end of experiments (day 7) were as follows, perindopril: 0.63, trandolapril: 0.62, quinapril: 0.41, enalapril: 0.27. The T/P of perindopril was significantly higher than that of enalapril. The results of the present studies testing four ACE inhibitors are well consistent with those in clinical trials. Thus, the measurement of T/P in SHR would provide a meaningful information for the evaluation of antihypertensive agents like ACE inhibitors.

Efficacy and safety of spirapril in mild-to-moderate hypertension

Spirapril is a new angiotensin-converting enzyme (ACE) inhibitor. It is a prodrug with a resorption of about 50%. The active metabolite spiraprilat reaches maximal plasma concentration within 2-3 h after oral administration. Spirapril can be administered once daily because of its long duration of action caused by an elimination half-life of about 40 h. It undergoes renal and hepatic elimination. In contrast to other ACE inhibitors it has a narrow dose range; therefore, the recommended dose is 6 mg for most patients without the need for dose titration. Spirapril has no relevant drug interactions. In several studies, spirapril was given to patients with mild-to-moderate essential hypertension at doses of 1-24 mg/day. There was an identical blood pressure lowering effect at doses of 6-24 mg/day; doses of 1-3 mg/day were less effective. Twenty-four-hour blood pressure monitoring showed a trough:peak ratio up to 0.84. In studies comparing the effect of spirapril with enalapril, lisinopril, trandolapril or captopril, spirapril was at least as effective as the other substances. Besides treating uncomplicated mild-to-moderate essential hypertension, spirapril can be used in patients with diseases accompanying hypertension such as heart and renal diseases, diabetes mellitus, and lipid disturbances. Possible advantages of spirapril compared to other ACE inhibitors are the dual mechanism of elimination, the lack of need for dose titration and a low incidence of cough.

Comparison between moexipril and atenolol in obese postmenopausal women with hypertension

The present study investigated the effect of the new ACE-inhibitor moexipril versus the beta 1-adrenergic blocker atenolol on metabolic parameters, adverse events (AEs) and sitting systolic (SSBP) and sitting diastolic blood pressure (SDBP) in obese postmenopausal women with hypertension (stage I and II). After a 4-week placebo run-in phase, 116 obese, postmenopausal women with primary hypertension were randomised into two treatment groups receiving once daily dosages of either moexipril 7.5 mg or atenolol 25 mg initially (mean age: 57 +/- 7 years in both groups; mean weight: 94 kg in the moexipril group and 89 kg in the atenolol group, corresponding to a body mass index (BMI) of 35.2 kg/m2 and 34.1 kg/m2 in both groups, respectively). After 4 and 8 weeks, the dosages were uptitrated to moexipril 15 mg, or if necessary to moexipril 15 mg/hydrochlorothiazide (HCTZ) 25 mg, or to atenolol 50 mg and atenolol 50 mg/HCTZ 25 mg, in patients whose blood pressure was not sufficiently controlled. At endpoint, metabolic parameters (total cholesterol, triglycerides, LDL, HDL, glucose, insulin) were not significantly altered in either treatment group. Most frequent adverse events under monotherapy (moexipril/atenolol) were asthenia (5.3/13.0%), headache (13.2/21.7%), cough (7.9/6.5%), pharyngitis (21.1/8.7%) and peripheral oedema (5.3/13.0%). Overall at least one AE was reported in 66% of the patients treated with moexipril and in 78% of those treated with atenolol. Reduction of SSBP/SDBP at endpoint was 14.7 +/- 1.9/10.0 +/- 1.1 and 8.7 +/- 1.9/8.4 +/- 1.1 mmHg after treatment with moexipril and atenolol, respectively. The results showed that moexipril and atenolol are equally effective in reducing blood pressure without adversely affecting blood lipids and carbohydrate metabolism.

Angiotensin-Converting Enzyme Inhibitors an Angiotensin II-Receptor Antagonists

The renin-angiotensin-aldosterone system (RAAS) is one of the main targets in the pharmacotherapy of cardiovascular diseases. Inhibitors of the angiotensin- converting enzyme (ACE) have been in clinical use for years and a great deal of experience exists with this particular group of drugs. However, the therapeutic effect is based on the inhibition of an enzyme (ACE) that is not very specific. Another substrate is bradykinin, a well-known mediator of inflammation and a potent inductor of vasodilatation and bronchoconstriction. Dur ing therapy with an ACE inhibitor, the inactivation of bradykinin by cleavage of the carboxyterminal end of this nonpeptide is blocked as well, with the result of bradykinin accumulation. The pattern of adverse effects seen with ACE inhibitors is mainly determined by bradykinin-mediated actions such as edema and cough. Therefore, the inhibition of the RAAS at the level of the transmitter-receptor interaction seems to be a logical development. Because nonpeptide (ie, orally active) angiotensin II (AT) receptor antagonists are available, this concept can be proven.

Use of angiotensin-converting enzyme inhibitors as monotherapy and in combination with diuretics and calcium channel blockers

Angiotensin-converting enzyme (ACE) inhibitors have earned an important place in medical therapy since their discovery about two decades ago. This family of drug has grown tremendously since the introduction of captopril in 1981. There are currently more than 14 ACE inhibitors in the world and 9 are available in the United States. Although these agents share many similarities, they differ in their pharmacokinetic properties, approved indications, and cost. This paper provides guidance for selection of ACE inhibitors by examining the pharmacokinetics, pharmacodynamics, drug interactions, adverse effects, and cost of these agents. Combination products of ACE inhibitors with either diuretics or calcium channel blockers also are reviewed.

Comparison of temocapril and atenolol in the long-term treatment of mild to moderate essential hypertension

This 1-year, dose-titration, General Practitioner (GP) study compared efficacy, tolerability and safety of oral temocapril (10-40 mg once daily) with atenolol (25-100 mg once daily) in mild to moderate adult hypertensives (diastolic blood pressure (DBP) 95-114 mmHg). A 12-week dose-titration period, randomized 3:1 temocapril: atenolol, preceded 40 weeks long-term treatment. An intent-to-treat population of 472 patients was analysed for efficacy after 12 weeks dose-titration. Sitting DBP fell significantly (p < 0.001) in both groups, by mean +/- standard deviation (SD) 15.9 +/- 5.7 mmHg on temocapril and by 16.6 +/- 5.9 mmHg on atenolol. Therapeutic equivalence was demonstrated using the two one-sided t-tests procedure according to Schuirmann (equivalence interval [theta 1 - theta 2] < or = 5 mmHg). Responders (DBP < or = 90 mmHg) represented 89.9% of temocapril and 94.0% of atenolol patients. The lower doses were effective in 70.9% of temocapril patients (10 or 20 mg) and in 63.7% of atenolol patients (25 or 50 mg), these doses being continued after the dose titration period. No clinically relevant changes in haematological, biochemical and urinalysis variables occurred. Adverse events were few, largely unrelated to treatment and comparable between groups. In conclusion, temocapril and atenolol proved to be therapeutically equivalent antihypertensives.