Lisinopril. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension and congestive heart failure

Benefit and risk evaluation of quinapril hydrochloride

INTRODUCTION

Angiotensin-converting enzyme (ACE) inhibitors are a mainstay of antihypertensive therapy. Quinapril hydrochloride, a less commonly used, and less-studied ACE inhibitor has been approved for its primary use in hypertension. Studies also indicate its off-label use for congestive heart failure and diabetic nephropathy. The ANDI and TREND trials have been pivotal in demonstrating the effectiveness of quinapril.

AREAS COVERED

The authors conducted a review of the literature analyzing the clinical efficacy and safety profile of quinapril. This review discusses the development of quinapril, provides an updated summary of the indications and contraindications, and presents a comparison with other ACE inhibitors.

EXPERT OPINION

Quinapril is a safe and well-tolerated antihypertensive medication with a favorable safety profile compared to other ACE inhibitors. However, a lack of ample recent clinical trials and post-marketing data investigating the efficacy of quinapril in large cohorts has resulted in limited use in clinical practice. Quinapril may be an effective antihypertensive option for elderly populations as well as those who cannot tolerate the side effects profiles of other ACE inhibitors and as an additional treatment option for patients with heart failure with preserved ejection fraction.

Discovery and biosynthesis of karnamicins as angiotensin converting enzyme inhibitors

Angiotensin-converting enzyme inhibitors are widely used for treatment of hypertension and related diseases. Here, six karnamicins E₁-E₆ (1-6), which bear fully substituted hydroxypyridine and thiazole moieties are characterized from the rare actinobacterium Lechevalieria rhizosphaerae NEAU-A2. Through a combination of isotopic labeling, genome mining, and enzymatic characterization studies, the programmed assembly of the fully substituted hydroxypyridine moiety in karnamicin is proposed to be due to sequential operation of a hybrid polyketide synthase-nonribosomal peptide synthetase, two regioselective pyridine ring flavoprotein hydroxylases, and a methyltransferase. Based on AlphaFold protein structures predictions, molecular docking, and site-directed mutagenesis, we find that two pyridine hydroxylases deploy active site residues distinct from other flavoprotein monooxygenases to direct the chemo- and regioselective hydroxylation of the pyridine nucleus. Pleasingly, karnamicins show significant angiotensin-converting enzyme inhibitory activity with IC₅₀ values ranging from 0.24 to 5.81 μM, suggesting their potential use for the treatment of hypertension and related diseases.

Prediction of lisinopril pediatric dose from the reference adult dose by employing a physiologically based pharmacokinetic model

Background

This study aimed to assess the pediatric lisinopril doses using an adult physiological based pharmacokinetic (PBPK) model. As the empirical rules of dose calculation cannot calculate gender-specific pediatric doses and ignores the age-related physiological differences.

Methods

A PBPK model of lisinopril for the healthy adult population was developed for oral (fed and fasting) and IV administration using PK-Sim MoBI® and was scaled down to a virtual pediatric population for prediction of lisinopril doses in neonates to infants, infants to toddler, children at pre-school age, children at school age and the adolescents. The pharmacokinetic parameters were predicted for the above groups at decremental doses of 20 mg, 10 mg, 5 mg, 2.5 mg, and 1.5 mg in order to accomplish doses producing the pharmacokinetic parameters, similar (or comparable) to that of the adult population. The above simulated pediatric doses were compared to the doses computed using the conventional four methods, such as Young’s rule, Clark’s rule, and weight-based and body surface area-based equations and the dose reported in different studies.

Results

Though the doses predicted for all subpopulations of children were comparable to those calculated by Young’s rule, yet the conventional methods overestimated the pediatric doses when compared to the respective PBPK-predicted doses. The findings of previous real time pharmacokinetic studies in pediatric patients supported the present simulated dose.

Conclusion

Thus, PBPK seems to have predictability potential for pediatric dose since it takes into consideration the physiological changes related to age and gender.

Pharmacological and Clinical Profile of Moexipril: A Concise Review

Angiotensin-converting enzyme (ACE) inhibitors are effective and safe antihypertensive drugs, with the exception of the rare occasion of angioedema. These drugs have demonstrated additional cardiovascular protective effects to their blood pressure lowering, and their combination with the diuretic hydrochlorothiazide potentiates their antihypertensive effectiveness. Moexipril is a long-acting ACE inhibitor suitable for once-daily administration, and like some ACE inhibitors, moexipril is a prodrug and needs to be hydrolyzed in the liver into its active carboxylic metabolite, moexiprilat, to become effective. Moexipril alone and in combination with low-dose hydrochlorothiazide has been shown in clinical trials to be effective in lowering blood pressure and be well tolerated and safe given in single daily doses. In this review, the pharmacological profile of this drug and its clinical usefulness are discussed.

Optimization of hydrogels for transdermal delivery of lisinopril by Box-Behnken statistical design

The aim of this study was to investigate the combined influence of three independent variables on the permeation kinetics of lisinopril from hydrogels for transdermal delivery. A three-factor, three-level Box-Behnken design was used to optimize the independent variables, Carbopol 971 P (X(1)), menthol (X(2)), and propylene glycol (X(3)). Fifteen batches were prepared and evaluated for responses as dependent variables. The dependent variables selected were cumulative amount permeated across rat abdominal skin in 24 h (Q (24); Y(1)), flux (Y(2)), and lag time (Y(3)). Aloe juice has been first time investigated as vehicle for hydrogel preparation. The ex vivo permeation study was conducted using Franz diffusion cells. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The regression equation generated for the cumulative permeation of LSP in 24 h (Q(24)) was Y(1) = 1,443.3-602.59X(1) + 93.24X(2) + 91.75X(3) - 18.95X(1)X(2) - 140.93X(1)X(3) - 4.43X(2)X(3) - 152.63X(1)(2) - 150.03X(2)(2) - 213.9X(3)(2). The statistical validity of the polynomials was established, and optimized formulation factors were selected by feasibility and grid search. Validation of the optimization study with 15 confirmatory runs indicated high degree of prognostic ability of response surface methodology. The use of Box-Behnken design approach helped in identifying the critical formulation parameters in the transdermal delivery of lisinopril from hydrogels.

Vaccine for hypertension: modulating the renin-angiotensin system

Hypertension, which is one of the most common diseases afflicting mankind, is associated to increased morbidity, mortality and cost to society. Cardiovascular disease is the leading cause of death all around the world and hypertension is the most common reversible risk factor for cardiovascular diseases. The renin-angiotensin system (RAS) commands an important role in the regulation of blood pressure, and so, at present, has been a target for clinical control by drugs acting on the system. Despite the fact that effective drugs are available, only about one out of three people has their blood pressure successfully controlled, and the blame goes to the undesirable side effects and the poor oral drug compliance. Keeping in mind the increasing incidence of hypertension and the patients' inconsistency for the polypharmacy, immunization against renin and the angiotensins, although with less success, had been attempted in the past. More recently, immunization against angiotensin-I with PMD-3117 vaccine, angiotensin-II with CYT006-AngQb vaccine and targeting angiotensin-II type 1A receptor with ATR12181 vaccine have provided optimism in the development of a hypertension vaccine. AngQb vaccine has proved to become the first vaccine ever to lower (-9/-4 mm Hg) blood pressure in human beings. Vaccine could induce long lasting effects with a dosing interval of months, increasing patient acceptability and compliance and thus a better control of high blood pressure. Our objective will be to focus on the importance of the RAS and to explore the extent of safety, efficacy and the future implications of vaccine against the RAS.

Characterization of a novel impurity in bulk drug of lisinopril by multidimensional NMR technique

During the routine impurity profile of lisinopril bulk drug by HPLC (high-performance liquid chromatography), a potential impurity was detected. Using multidimensional NMR (nuclear magnetic resonance) technique, the trace-level impurity was unambiguously identified to be 2-(-2-oxo-azocan-3-ylamino)-4-phenyl-butyric acid after isolation from lisinopril bulk drug by semi-preparative HPLC. Formation of the impurity was also discussed. To our knowledge, this is a novel impurity and not reported elsewhere.

Characterization of a novel trace-level impurity in lisinopril using multi-stage mass spectrometry

An impurity in the bulk drug lisinopril was detected by simple reversed-phase high-performance liquid chromatography (HPLC). This trace-level impurity was rapidly identified as 2-(2-oxo-azocan-3-ylamino)-4-phenyl- butyric acid on the basis of the on-line multi-stage mass spectrometric evidence, and the proposed structure was further confirmed by multi-stage mass spectrometry of lisinopril and three related compounds.

Development of a liquid chromatography/tandem mass spectrometry assay for the quantification of lisinopril in human plasma

A simple and sensitive liquid chromatography/tandem mass spectrometry method employing electrospray ionization, to quantify lisinopril in human plasma using pseudoephedrine hydrochloride as the internal standard (IS), has been developed and validated. A mixture of methanol and 0.1% formic acid in water (50:50, v/v) was used as the isocratic mobile phase. A simple liquid-liquid extraction procedure was used as sample preparation method. The method validation demonstrated the specificity, lower limit of quantification, accuracy, and precision of measurements. Selected reaction monitoring was specific for lisinopril and pseudoephedrine hydrochloride; no endogenous materials from blank plasma interfered with the analysis of lisinopril or the IS. The assay was linear over the concentration range 0.78-100 ng/mL. The correlation coefficients for the calibration curves ranged from 0.9984-0.9998. The intra- and inter-day precision, determined for quality control samples, were less than 4.18%. The method was employed in a pharmacokinetic study after oral administration of 10 mg lisinopril to 20 healthy volunteers.

Effect of telmisartan/hydrochlorothiazide vs lisinopril/hydrochlorothiazide combination on ambulatory blood pressure and cognitive function in elderly hypertensive patients

The aim of this study was to compare the effects of telmisartan/hydrochlorothiazide (HCTZ) vs lisinopril/HCTZ combination on ambulatory blood pressure and cognitive function in elderly hypertensive patients. A total of 160 patients, 76 men and 84 women, aged 61-75 years, with sitting diastolic blood pressure (DBP)>90 mmHg and <110 mmHg and systolic blood pressure (SBP)>140 mmHg were randomized to receive temisartan 80 mg/HCTZ 12.5 mg o.d. or lisinopril 20 mg/HCTZ 12.5 mg o.d. for 24 weeks, according to a prospective, open-label, blinded end point, parallel-group design. At the end of a 2-week wash-out period and after 12 and 24 weeks of active treatment, 24-h noninvasive ambulatory BP monitoring (ABPM) was performed and cognitive function was evaluated through six different tests (verbal fluency, Boston naming test, word-list memory, word-list recall, word-list recognition and Trails B). Both treatments significantly reduced ambulatory BP. However, the telmisartan/HCTZ combination produced a greater reduction in 24-h, day-time and night time ABPM values. Lisinopril/HCTZ did not induce significant changes in any of the cognitive function test scores at any time of the study, whereas at both 12 and 24 weeks telmisartan/HCTZ significantly improved the word-list memory score (+17.1 and +15.7%, respectively, P<0.05 vs baseline), the word-list recall score (+13.5 and +16.9%, P<0.05) and the Trails B score (-33 and -30.5%, P<0.05). These results suggest that in elderly hypertensive patients treatment with telmisartan/HCTZ produces a slightly greater reduction in ambulatory BP than lisinopril/HCTZ combination and, unlike this latter, improves some of the components of cognitive function, particularly episodic memory and visuospatial abilities.

Effect of successful hypertension control by manidipine or lisinopril on albuminuria and left ventricular mass in diabetic hypertensive patients with microalbuminuria

OBJECTIVE

The aim of this open-labelled, randomised, parallel-group study was to evaluate the effect of long-term monotherapy with manidipine or lisinopril on albumin excretion rate (AER) and left ventricular mass index (LVMI) in hypertensive patients with type-2 diabetes and microalbuminuria.

METHODS

After a 4-week wash-out period, 174 patients with essential hypertension [diastolic blood pressure (DBP) >80 mmHg and <100 mmHg], type-2 diabetes and microalbuminuria were randomised to manidipine 10 mg o.d. or lisinopril 10 mg o.d.; after 8 weeks, the dose was doubled in non-responders (DBP >80 mmHg); after 3 months, treatment was discontinued in the non-responder patients and in those complaining of side effects; the remaining 121 patients continued their therapy with manidipine or lisinopril, and 99 completed the 2-year study. At the end of the wash-out period, of the titration period and after 6, 12, 18 and 24 months of treatment, BP was measured, AER, creatinine clearance, glycosylated haemoglobin (HbA1c) and body mass index (BMI) were evaluated and an echocardiographic evaluation was performed.

RESULTS

The 99 patients who completed the study were statistically analysed according to a per-protocol evaluation. Manidipine and lisinopril significantly reduced systolic blood pressure (SBP) and DBP levels (at 24 months, --22.3/15.5 mmHg, P<0.001 versus baseline and --21.4/15.7 mmHg, P<0.01 versus baseline, respectively). Both drugs provided a significant decrease in AER, but it was significantly more pronounced with lisinopril (at 24 weeks, --37.2 mg/24 h, P<0.001 versus baseline) than with manidipine (--29.9 mg/24 h, P<0.05 versus baseline) and became evident earlier in the lisinopril group (after 3 months versus 6 months of treatment). Manidipine produced a greater reduction of LVMI than lisinopril (--14.9 g/m(2) versus --10.8 g/m(2) at 24 months). The effect was more pronounced in patients with left ventricular hypertrophy at baseline (--19.8 g/m(2) versus --12.8 g/m(2), P<0.05).

CONCLUSION

These data suggest that, despite similar BP lowering, non-haemodynamic factors play an important role in the pharmacological reduction of AER and LVMI in diabetic hypertensive patients.

Application of π-acceptors to the spectrophotometric determination of lisinopril in commercial dosage forms

Two simple, rapid and sensitive spectrophotometric methods have been proposed for the determination of lisinopril in pure form and pharmaceutical formulations. The methods are based on the charge transfer complexation reaction of the drug with 7,7,8,8,tetracyanoquinodimethane (TCNQ) and p-chloranilic acid (pCA) in polar media. The lisinopril-TCNQ and lisinopril-pCA charge transfer complexes dissociate in acetone and methanol, respectively, and yield coloured TCNQ and pCA radical anions which are measured spectrophotometrically at 743 and 525 nm. Under optimised experimental conditions, Beer's law is obeyed in the concentration range of 2-26 and 25-300 microg ml-1 with molar absorptivity of 1.432x10(4) and 1.192x10(4) l mol-1 cm-1 for TCNQ and pCA methods, respectively. Both the methods have been applied to the determination of lisinopril in pharmaceutical dosage forms. Results of analysis are validated statistically.

Lisinopril quantification in human plasma by liquid chromatography–electrospray tandem mass spectrometry

An analytical method based on liquid chromatography with positive ion electrospray ionization (ESI) coupled to tandem mass spectrometry detection was developed for the determination of Lisinopril in human plasma using Enalaprilat as internal standard. The analyte and internal standard were extracted from the plasma samples by solid-phase extraction using Waters HLB Oasis SPE cartridges and chromatographed on a C8 analytical column. The mobile phase consisted of acetonitrile/water (60:40, v/v) + 20 mM acetic acid + 4.3 mM of triethylamine. The method had a chromatographic total run-time of 6.5 min and was linear within the range 2.00-200 ng/ml. Detection was carried out on a Micromass triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM). The precision (CV%) and accuracy, calculated from limit of quantification (LOQ) samples (n = 8), were 8.9 and 98.9%, respectively. The method herein described was employed in a bioequivalence study of two tablet formulations of Lisinopril 20mg.

An HPLC method for the determination of lisinopril in human plasma and urine with fluorescence detection

A selective, sensitive and precise HPLC method with fluorimetric detection has been developed for the assay of lisinopril in human plasma and urine. The clean up of the sample was carried out by solid-phase extraction, firstly with C18-cartridge and secondly with a silica-cartridge. After a pre-column derivatization with fluorescamine, the reaction mixture was chromatographed on C18-column with gradient elution, using methanol and 0.02 M phosphate buffer (pH=3.2). The fluorescamine-lisinopril derivative was detected fluorimetrically by monitoring the emission at 477 nm, with excitation at 383 nm. Linear quantitative response curve was generated over a concentration range of 5-200 ng/ml and 25-1000 ng/ml for plasma and urine samples, respectively. The mean recovery of lisinopril from plasma and urine was 63.41 and 74.08%, respectively. Intra-day and inter-day R.S.D. and R.M.E. values at three different concentrations were assessed. The method was applied for pharmacokinetic study in a healthy volunteer after a single oral dose of 20 mg of the drug.

Combination therapy with ACE inhibitors/angiotensin II receptor antagonists and diuretics in hypertension

Essential hypertension is a very heterogeneous disease and different pressor mechanisms might interact to increase blood pressure. It is therefore not surprising that antihypertensive drugs, given as monotherapy, normalize blood pressure in only a fraction of hypertensive patients. This is, for instance, the case for diuretics, angiotensin converting enzyme (ACE) inhibitors and angiotensin II (AT1) receptor antagonists administered as single agents. The rationale for combining antihypertensive agents relates in part to the concept that the blood pressure-lowering effect may be enhanced when two classes are coadministered. Also, combination therapy serves to counteract counter-regulatory mechanisms that are triggered whenever pharmacologic intervention is initiated and that act to limit the efficacy of the antihypertensive medication. For example, the compensatory rise in renin secretion induced by sodium depletion may become the predominant factor sustaining high blood pressure. Simultaneous blockade of the renin-angiotensin system, with either an ACE inhibitor or an AT1-receptor blocker, makes this compensatory hyper-reninemia ineffective and allows maximum benefit from sodium depletion. The combination of a blocker of the renin-angiotensin system and a low dose of a diuretic increases the effectiveness, but not at the expense of tolerability compared with the individual components administered alone. Fixed-dose combinations containing an ACE inhibitor or an AT1-receptor blocker and a diuretic are therefore likely to become increasingly used not only as second-line therapy but also as first-line treatment.

Pharmacological profile and clinical use of moexipril

Angiotensin-converting enzyme (ACE) inhibitors are effective and safe antihypertensive drugs with the exception of the rare occurrence of angioedema. These drugs have demonstrated additional cardiovascular protective effects to their blood pressure lowering and their combination with the diuretic hydrochlorothiazide potentiates their antihypertensive effectiveness. Moexipril (Univasc, Bayer) is a long-acting ACE inhibitor suitable for once-daily administration and, like enalapril, is a prodrug and needs to be hydrolyzed in the liver into its active carboxylic metabolite, moexiprilat, in order to become effective. Moexipril alone and in combination with low-dose hydrochlorothiazide has been shown in clinical trials to be effective in lowering blood pressure and to be well-tolerated and safe given in single daily doses. In this review, the pharmacological profile of this drug and its clinical usefulness will be discussed.

A new spectrofluorimetric method for the determination of lisinopril in tablets

An accurate and precise spectrofluorimetric method is presented for the determination of lisinopril based on the formation of a derivative formed with 7-chloro-4-nitrobenzofurazan. The derivatization reaction proceeds quantitatively at pH 8.5-9.0 and 60 degrees C in 70 min when the molar ratio of reagent to the drug is 170. After the extraction with ethyl acetate the fluorescence intensity of the derivative was measured at 528 nm with excitation at 465 nm. Calibration graph is rectilinear over the range of 50-1000 ng/ml with detection and determination limits of 20 and 50 ng/ml, respectively. The regression equation is I(f) = 0.198C-0.299 (r = 0.9999). The method was applied to the commercially available tablets and the results were statistically compared with those obtained by official HPLC method.

Development of a liquid chromatography-mass spectrometry method for monitoring the angiotensin-converting enzyme inhibitor lisinopril in serum

In this study, a sensitive, specific, precise and accurate method for lisonopril quantitative determination in human serum was developed and validated. The method comprises lisinopril isolation from serum by means of solid-phase extraction followed by its quantification by liquid chromatography-mass spectrometry. Chromatographic separation was performed at 55 degrees C on Kromasil C(18) 5 micrometer 250x3.2 mm HPLC column with mobile phase composed of 50 mM ammonium formate buffer (pH 3)-acetonirile-methanol (72:7:21, v/v/v). A Finnigan AQA benchtop mass spectrometer with a pneumatically assisted electrospray (ES) interface and a single quadrupole mass filter was used to detect and quantify lisinopril in column effluent. Ion signals were acquired by selected ion monitoring of the protonated lisinopril ion m/z=406.5 (M+1). The detector response was linear with r>0.9993 in the investigated concentration range 6-150 ng/ml. The mean recovery of lisinopril from serum samples was 88%. The limit of quantitation for lisinopril was 6 ng/ml with a signal-to-noise ratio at this concentration level S/N=34.75+/-3.9 (n=4).

Evaluation of human intestinal absorption data and subsequent derivation of a quantitative structure–activity relationship (QSAR) with the Abraham descriptors

The human intestinal absorption of 241 drugs was evaluated. Three main methods were used to determine the human intestinal absorption: bioavailability, percentage of urinary excretion of drug-related material following oral administration, and the ratio of cumulative urinary excretion of drug-related material following oral and intravenous administration. The general solvation equation developed by Abraham's group was used to model the human intestinal absorption data of 169 drugs we considered to have reliable data. The model contains five Abraham descriptors calculated by the ABSOLV program. The results show that Abraham descriptors can successfully predict human intestinal absorption if the human absorption data is carefully classified based on solubility and administration dose to humans.

Regression of left ventricular hypertrophy by lisinopril after renal transplantation: role of ACE gene polymorphism

BACKGROUND

Cardiac complications are the main cause of death in renal transplantation (RT), and left ventricular hypertrophy (LVH) may play an important role in these patients. The unfavorable genotype of the angiotensin-converting enzyme (ACE) gene has been associated with cardiovascular disease, including LVH. ACE inhibitors (ACEIs) reduce LVH, but little is known about the effects of ACEIs on LVH in RT patients with different insertion/deletion (I/D) genotypes of the ACE gene.

METHODS

We prospectively studied 57 stable nondiabetic RT patients with hypertension and echocardiographic LVH as well as a functional graft for 69.5 +/- 5.6 months. Patients randomly received either lisinopril 10 mg/day (group A, N = 29; 5 were excluded due to reversible acute renal failure) or placebo (group B, N = 28) for 12 months. Echocardiography (M-mode, 2-B, and color flow Doppler) was performed at baseline and 6 and 12 months later by the same examiner without previous knowledge of the genetic typing. The ACE genotype (I or D alleles) was ascertained by polymerase chain reaction (PCR; group A, DD = 10 and ID/II = 14; group B, DD = 15 and ID/II = 13).

RESULTS

All patients maintained a good renal function (serum creatinine <2.5 mg/dL) during the follow-up and both groups received a similar proportion of antihypertensive drugs (beta-blockers 83 vs. 79%; Ca antagonists 66 vs. 68%; alpha1-adrenoreceptor antagonists 50 vs. 67%) during the study. As expected, mean arterial blood pressure and hemoglobin levels showed a higher percentage reduction in group A versus group B (-4 +/- 2.8 vs. 2.1 +/- 2.6%, P = 0.07, and -11.5 +/- 1.5 vs. -0.5 +/- 2.3%, P < 0.01, respectively). Group A patients showed a significantly higher decrement in LV mass index (LVMI) than group B at the end of follow-up, after adjusting for age, baseline LVMI, time after grafting and changes in systolic blood pressure, renal function, and hemoglobin levels (group A, -9.5 +/- 3.5% vs. group B, 3 +/- 3.2%, P < 0.05). As a result, 46% of group A and only 7% of group B patients showed a reduction of LVMI >/=15% (P < 0.01). The beneficial effect of lisinopril on LVMI reduction was more evident in DD patients (placebo DD, 8.4 +/- 4.1% vs. lisinopril DD, -7.2 +/- 5.3, P < 0.05), and a trend was observed in patients with other genotypes (placebo ID/II, 2.8 +/- 5.4% vs. lisinopril ID/II, -11.4 +/- 5%, P = 0.33).

CONCLUSIONS

Lisinopril decreases LVM in renal transplant patients with hypertension and LVH, and the ACE gene polymorphism may predict the beneficial effect of this therapy. This finding may be important in targeting prophylactic interventions in this population.

Effects on plasma angiotensin-converting enzyme activity and circulating renin of lisinopril and enalapril alone and in combination with propranolol in healthy volunteers

The effects on plasma angiotensin-converting enzyme activity and renin activity of the two long-acting angiotensin-converting enzyme inhibitors, lisinopril and enalapril, alone and in combination with propranolol were studied. In an open, randomised, cross-over design 12 healthy volunteers received orally enalapril 20 mg alone, enalapril 20 mg in combination with propranolol 80 mg, lisinopril 20 mg alone, and lisinopril 20 mg in combination with propranolol 80 mg. Plasma angiotensin-converting enzyme activity and plasma renin activity were measured for 24 h after each treatment period. Lisinopril and enalapril reduced plasma angiotensin converting enzyme activity substantially and equally at six hr (-70%, P<0.05) and 12 hr (-65%, P<0.05), irrespective of combination with propranolol. At 24 hr plasma angiotensin-converting enzyme activity remained significantly suppressed only after lisinopril (-60%, P<0.05). Plasma renin activity increased almost ten times after ingestion of both angiotensin-converting enzyme inhibitors, but the effect lasted significantly longer after lisinopril than after enalapril. Beta-Adrenergic blockade blunted the effect on the increase in plasma renin activity induced by both angiotensin-converting enzyme inhibitors. Our results show that the effect of lisinopril on plasma angiotensin-converting enzyme activity and plasma renin activity lasted longer than that of enalapril. beta-Adrenergic blockade suppressed the effect on elevated plasma renin activity, but did not influence the effect of angiotensin-converting enzyme inhibitors on plasma angiotensin-converting enzyme activity.

Comparative effects of lisinopril and losartan on insulin sensitivity in the treatment of non diabetic hypertensive patients

AIMS

The aim of this study was to compare the effects of the ACE-inhibitor lisinopril and the angiotensin II receptor antagonist losartan on insulin sensitivity in the treatment of non diabetic hypertensives.

METHODS

Twenty-five non diabetic subjects with mild to moderate hypertension, 11 females and 14 males, aged 44-63 years, after a 4-week wash-out period on placebo, were randomized to receive lisinopril 20 mg once daily or losartan 50 mg once daily for 6 weeks. Following another 4-week wash-out period, patients were crossed to the alternative regimen for further 6 weeks. At the end of the placebo and of the active treatment periods, blood pressure (BP) was measured (by standard mercury sphygmomanometer, Korotkoff I and V) and insulin sensitivity was assessed by the euglycaemic hyperinsulinaemic clamp technique. Glucose infusion rate (GIR) during the last 30 min of clamp and total glucose requirement (TGR) were evaluated.

RESULTS

Both lisinopril and losartan significantly reduced SBP (by a mean of 20.2 and 17.2 mmHg, respectively) and DBP (by a mean of 15.2 and 12.3 mmHg, respectively), with no difference between the two treatments. GIR, used as an indicator of insulin sensitivity, was significantly increased by lisinopril (+1.5 mg min(-1) kg(-1), P<0.05 vs baseline) but not by losartan (+0.42 mg min(-1) kig(-1), NS), the difference between the two drugs being statistically significant (P<0.05). TGR was increased by lisinopril (+7.3 g, P<0.05 vs baseline), whereas losartan did not significantly modify it (+1.9 g, NS).

CONCLUSIONS

In conclusion, with all cautions due to an absence in this study of a randomized placebo phase, our findings suggest that lisinopril improved insulin sensitivity whereas losartan did not affect it.

Single dose and steady state pharmacokinetics of temocapril and temocaprilat in young and elderly hypertensive patients

AIMS

The aim of this study was to determine the potential impact of age on the pharmacokinetics of temocapril and its pharmacologically active diacid metabolite, temocaprilat, in hypertensive patients.

METHODS

Male and female patients with mild to moderate essential hypertension (DBP 95-114 mmHg inclusive) were allocated to two age groups: young, < or = 40 years; elderly, > or = 69 years, (n = 18 per group). In Part I of the study, subjects took a single oral tablet dose of 20 mg temocapril hydrochloride following an overnight fast. In Part II they took seven once daily oral tablet doses of 20 mg temocapril hydrochloride. Pharmacokinetic profiles were determined after the single and the last dose. Trough plasma samples were taken before each dose in Part II. Urine was collected for 24 h following the single and the last dose.

RESULTS

Steady state was reached within 1 week in both groups. Statistically significant differences were detected in AUC and AUCss for temocaprilat as well as in CL(R) for temocapril and temocaprilat, respectively, after a single dose and at steady state. All other pharmacokinetic parameters for temocapril and temocaprilat did not show any significant difference.

CONCLUSIONS

The pharmacokinetic differences detected in the elderly do not require a dose adjustment per se. Nonetheless, a lower starting dose may be appropriate as elderly hypertensive patients are usually considered to be at an increased risk of first dose hypotension at the onset of treatment with an ACE inhibitor.

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.

Clinical pharmacokinetics of vasodilators. Part I

Understanding the mechanism of action and the pharmacokinetic properties of vasodilatory drugs facilitates optimal use in clinical practice. It should be kept in mind that a drug belongs to a class but is a distinct entity, sometimes derived from a prototype to achieve a specific effect. The most common pharmacokinetic drug improvement is the development of a drug with a half-life sufficiently long to allow an adequate once-daily dosage. Developing a controlled release preparation can increase the apparent half-life of a drug. Altering the molecular structure may also increase the half-life of a prototype drug. Another desirable improvement is increasing the specificity of a drug, which may result in fewer adverse effects, or more efficacy at the target site. This is especially important for vasodilatory drugs which may be administered over decades for the treatment of hypertension, which usually does not interfere with subjective well-being. Compliance is greatly increased with once-daily dosing. Vasodilatory agents cause relaxation by either a decrease in cytoplasmic calcium, an increase in nitric oxide (NO) or by inhibiting myosin light chain kinase. They are divided into 9 classes: calcium antagonists, potassium channel openers, ACE inhibitors, angiotensin-II receptor antagonists, alpha-adrenergic and imidazole receptor antagonists, beta 1-adrenergic agonist, phosphodiesterase inhibitors, eicosanoids and NO donors. Despite chemical differences, the pharmacokinetic properties of calcium antagonists are similar. Absorption from the gastrointestinal tract is high, with all substances undergoing considerable first-pass metabolism by the liver, resulting in low bioavailability and pronounced individual variation in pharmacokinetics. Renal impairment has little effect on pharmacokinetics since renal elimination of these agents is minimal. Except for the newer drugs of the dihydropyridine type, amlodipine, felodipine, isradipine, nilvadipine, nisoldipine and nitrendipine, the half-life of calcium antagonists is short. Maintaining an effective drug concentration for the remainder of these agents requires multiple daily dosing, in some cases even with controlled release formulations. However, a coat-core preparation of nifedipine has been developed to allow once-daily administration. Adverse effects are directly correlated to the potency of the individual calcium antagonists. Treatment with the potassium channel opener minoxidil is reserved for patients with moderately severe to severe hypertension which is refractory to other treatment. Diazoxide and hydralazine are chiefly used to treat severe hypertensive emergencies, primary pulmonary and malignant hypertension and in severe preeclampsia. ACE inhibitors prevent conversion of angiotensin-I to angiotensin-II and are most effective when renin production is increased. Since ACE is identical to kininase-II, which inactivates the potent endogenous vasodilator bradykinin, ACE inhibition causes a reduction in bradykinin degradation. ACE inhibitors exert cardioprotective and cardioreparative effects by preventing and reversing cardiac fibrosis and ventricular hypertrophy in animal models. The predominant elimination pathway of most ACE inhibitors is via renal excretion. Therefore, renal impairment is associated with reduced elimination and a dosage reduction of 25 to 50% is recommended in patients with moderate to severe renal impairment. Separating angiotensin-II inhibition from bradykinin potentiation has been the goal in developing angiotensin-II receptor antagonists. The incidence of adverse effects of such an agent, losartan, is comparable to that encountered with placebo treatment, and the troublesome cough associated with ACE inhibitors is absent.

Lisinopril. A review of its pharmacology and use in the management of the complications of diabetes mellitus

Lisinopril, like other ACE inhibitors, lowers blood pressure and preserves renal function in hypertensive patients with non-insulin-dependent or insulin-dependent diabetes mellitus (NIDDM or IDDM) and early or overt nephropathy, without adversely affecting glycaemic control or lipid profiles. On available evidence, renoprotective effects appear to be greater with lisinopril than with comparator calcium channel blockers, diuretics and beta-blockers, despite similar antihypertensive efficacy. As shown by the EUCLID (EUrodiab Controlled trial of Lisinopril in Insulin-Dependent Diabetes) trial, lisinopril is also renoprotective in normotensive patients with IDDM and microalbuminuria. The effect in normotensive patients with normoalbuminuria was smaller than in those with microalbuminuria, and no conclusions can yet be made about its use in patients with normoalbuminuria. In complications other than nephropathy, lisinopril has shown some benefit. Progression to retinopathy was slowed during 2 years' lisinopril therapy in the EUCLID study. Although not yet fully published, these results provide the most convincing evidence to date for an effect of an ACE inhibitor in retinopathy. The drug may also improve neurological function, but this finding is preliminary. Lastly, post hoc analysis of the GISSI-3 trial indicates that lisinopril reduces 6-week mortality rates in diabetic patients when begun as early treatment after an acute myocardial infarction. The tolerability profile of lisinopril is typical of ACE inhibitors and appears to be similar in diabetic and nondiabetic individuals. Hypoglycaemia has occurred at a similar frequency with lisinopril and placebo, as shown in the EUCLID trial. In addition, the GISSI-3 study indicates that the incidence of persistent hypotension and renal dysfunction is increased with lisinopril in general, but the presence of diabetes does not appear to confer additional risk of these events in diabetic patients with acute myocardial infarction receiving lisinopril. In summary, lisinopril lowers blood pressure and produces a renoprotective effect in patients with IDDM and NIDDM without detriment to glycaemic control or lipid profiles. Like other ACE inhibitors, lisinopril should thus be viewed as a first-line agent for reducing blood pressure and preventing or attenuating nephropathy in hypertensive diabetic patients with IDDM or NIDDM and microalbuminuria or overt renal disease. The EUCLID study, using lisinopril, provides new data supporting an additional place in managing normotensive patients with microalbuminuria and IDDM. These findings, together with some evidence for an effect of lisinopril in delaying progression of retinopathy and in reducing mortality, suggest a broader role for the drug in managing diabetic vascular complications.

Lisinopril. A review of its pharmacology and clinical efficacy in elderly patients

Lisinopril, the lysine analogue of enalaprilat, is a long-acting angiotensin converting enzyme (ACE) inhibitor which is administered once daily by mouth. The efficacy of lisinopril in reducing blood pressure is well established in younger populations, and many trials now show it to be effective in lowering blood pressure in elderly patients with hypertension. In comparative and non-comparative clinical trials, 68.2 to 89.1% of elderly patients responded (diastolic pressure < or = 90 mm Hg) to > or = 8 weeks' lisinopril treatment. Age-related differences in antihypertensive efficacy do not appear to be clinically significant, and dosages effective in elderly patients tend to range from 2.5 to 40 mg/day. Dosages usually need to be lower in patients with significant renal impairment. In congestive heart failure, lisinopril 2.5 to 20 mg/day increases exercise duration, improves left ventricular ejection fraction and has no significant effect on ventricular ectopic beats. It is similar in efficacy to enalapril and digoxin and similar or superior to captopril on most end-points. Data from the GISSI-3 post-myocardial infarction trial show that lisinopril reduced mortality and left ventricular dysfunction when given for 42 days starting within 24 hours of the onset of infarction symptoms. Results at 6 weeks and 6 months were similar in elderly and younger patients. Elderly patients, however, among other subgroups, exhibited a strong reduction in risk of low ejection fraction after treatment (-25.5%). Economic studies suggest that lisinopril is cost saving compared with other ACE inhibitors in some markets. When given according to the GISSI-3 protocol, lisinopril appears to be one of the less expensive of the successful ACE inhibitor regimens for acute myocardial infarction. In other trials, patients with diabetic nephropathy and hypertension improved or did not deteriorate during lisinopril treatment. Blood pressure was controlled and reductions or trends towards reductions in albuminuria were observed. These reductions were similar to those in diltiazem, nifedipine and verapamil recipients, and greater than those in patients receiving atenolol. Lisinopril appears to reduce mortality in diabetic patients after myocardial infarction and may also improve neuropathy associated with diabetes. Lisinopril is well tolerated and the profile of adverse events seen is typical of ACE inhibitors as a class. There is a tendency for more elderly than younger patients to discontinue treatment, but this trend is not clearly related to the incidence of adverse events in these age groups. Drug interactions occur with few other agents and are usually clinically significant only between lisinopril and either diuretics or lithium. Lisinopril is, thus, an effective treatment for elderly patients with hypertension, congestive heart failure and acute myocardial infarction and has shown promising benefits in patients with diabetic nephropathy.

Lisinopril. A review of its pharmacology and clinical efficacy in the early management of acute myocardial infarction

Following establishment of its efficacy in hypertension and congestive heart failure, the ACE inhibitor lisinopril has now been shown to reduce mortality and cardiovascular morbidity in patients with myocardial infarction when administered as early treatment. The ability of lisinopril to attenuate the detrimental effects of left ventricular remodelling is a key mechanism; however, additional cardioprotective and vasculoprotective actions are postulated to play a role in mediating the early benefit. The GISSI-3 trial in > 19 000 patients has demonstrated that, when given orally within 24 hours of symptom onset and continued for 6 weeks, lisinopril (with or without nitrates) produces measurable survival benefits within 1 to 2 days of starting treatment. Compared with no lisinopril treatment, reductions of 11% in risk of mortality and 7.7% in a combined end-point (death plus severe left ventricular dysfunction) were evident at 6 weeks. Advantages were apparent in all types of patients. Thus, those at high risk-women, the elderly, patients with diabetes mellitus and those with anterior infarct and/or Killip class > 1 -also benefited. These gains in combined end-point events persisted in the longer term, despite treatment withdrawal after 6 weeks in most patients. At 6 months, the incidence rate for the combined end-point remained lower than with control (a 6.2% reduction). The GISSI-3 results concur with those from recent large investigations (ISIS-4, CCS-1, SMILE) of other ACE inhibitors as early management in myocardial infarction. However, the results of the CONSENSUS II trial (using intravenous enalaprilat then oral enalapril) were unfavourable in some patients. These findings, together with the development of persistent hypotension and, to a lesser extent, renal dysfunction among patients in the GISSI-3 trial, have prompted considerable debate over optimum treatment strategies. Present opinion generally holds that therapy with lisinopril or other ACE inhibitors shown to be beneficial may be started within 24 hours in haemodynamically stable patients with no other contraindications; current labelling in the US and other countries reflects this position. There is virtually unanimous agreement that such therapy is indicated in high-risk patients, particularly those with left ventricular dysfunction. The choice of ACE inhibitor appears less important than the decision to treat; it seems likely that these benefits are a class effect. Lisinopril has a tolerability profile resembling that of other ACE inhibitors, can be given once daily and may be less costly than other members of its class. However, present cost analyses are flawed and this latter points remains to be proven in formal cost-effectiveness analyses. In conclusion, early treatment with lisinopril (within 24 hours of symptom onset) for 6 weeks improves survival and reduces cardiovascular morbidity in patients with myocardial infarction, and confers ongoing benefit after drug withdrawal. While patients with symptoms of left ventricular dysfunction are prime candidates for treatment, all those who are haemodynamically stable with no other contraindications are also eligible to receive therapy. Lisinopril and other ACE inhibitors shown to be beneficial should therefore be considered an integral part of the early management of myocardial infarction in suitable patients.

Effect of 1 year of lisinopril treatment on cardiac autonomic control in hypertensive patients with left ventricular hypertrophy

In this study we evaluated in hypertensive patients the effects of drug-induced left ventricular hypertrophy regression on cardiac autonomic control, as assessed by means of heart period variability analysis. Power spectral analysis of 24-hour electrocardiographic monitoring was performed in 30 hypertensive patients with left ventricular hypertrophy at baseline, after 1 year of lisinopril treatment, and after 1 month of drug withdrawal. At the same times, patients underwent 24-hour blood pressure monitoring, echocardiographic study, and plasma renin activity assessment. Lisinopril treatment increased plasma renin activity and reduced 24-hour systolic and diastolic pressures (from 159 +/- 14 to 121 +/- 8 and from 103 +/- 7 to 80 +/- 3 mm Hg, respectively) and left ventricular mass index (from 159 +/- 33 to 134 +/- 26 g/m2); moreover, in 12 of 30 patients, left ventricular mass normalization was achieved. Drug withdrawal was followed by an increase in blood pressure without left ventricular mass modification. In the total study population, only high-frequency power was higher after lisinopril treatment. In the subgroup of patients with left ventricular mass normalization, daytime and nighttime high-frequency powers as well as nighttime total and very-low-frequency powers were higher after 1 year of treatment than at baseline. In the remaining 18 patients, power spectral measures after treatment were slightly lower than at baseline and were even lower after drug withdrawal. Thus, in hypertensive hypertrophic patients, lisinopril treatment improves sympathovagal imbalance when left ventricular mass normalization is achieved. In patients without left ventricular mass normalization, drug withdrawal is followed by a worsening of neural cardiac control.

Effects of lisinopril in patients with heart failure and chronic atrial fibrillation

Although atrial fibrillation is common in patients with heart failure, patients with atrial fibrillation are often excluded from congestive heart failure trials or are not analyzed separately. Consequently, while the effect of angiotensin-converting enzyme inhibitors in patients with sinus rhythm is well established, the effect on patients with atrial fibrillation is unknown. The authors hypothesized that these agents might be particularly effective in this patient category, given their antiadrenergic properties and the importance of adequate rate control. Therefore, the effects of lisinopril 10 mg once daily were evaluated in 30 patients with congestive heart failure and chronic atrial fibrillation (mean age, 68 +/- 6 years) in a double-blind, randomized, placebo-controlled trial. All patients were in New York Heart Association class II or III and were stable on conventional therapy (digoxin, diuretics, nitrates). After 6 weeks, mean peak oxygen consumption increased from 14.7 +/- 3.4 to 15.9 +/- 2.9 mL/min/kg in the lisinopril group (P = .034). Plasma norepinephrine levels during exercise and at peak exercise tended to be lower when the patients were taking lisinopril (10.8 +/- 4.2 to 8.9 +/- 4.4 nmol/L and 16.3 +/- 9.2 to 14.3 +/- 7.7 nmol/L, P < .1). Heart rate during exercise and ambulatory monitoring was not significantly affected. Left ventricular fractional shortening tended to increase after lisinopril (23 +/- 7 to 27 +/- 9%, P = .073). Left atrial volume was unchanged, as were plasma atrial natriuretic peptide levels. After subsequent electrical cardioversion, treatment was continued for 6 more weeks, allowing assessment of the effect of lisinopril on maintenance of sinus rhythm; maintenance of sinus rhythm was 71% in the lisinopril group and 36% in the placebo group (P = NS). This study shows that treatment with an angiotensin- converting enzyme inhibitor improves peak oxygen consumption in patients with congestive heart failure and chronic atrial fibrillation. Attenuation of adrenergic drive during exercise may play a role in mediating this effect.

Determination of the angiotensin-converting enzyme inhibitor lisinopril in urine using solid-phase extraction and reversed-phase high-performance liquid chromatography

A simple, accurate and precise high-performance liquid chromatographic method is described for assaying lisinopril in human urine. Urine (1 ml) containing lisinopril and enalaprilat (internal standard) was acidified with 10 microliters of 6 M nitric acid, passed through a Sep-Pak C18 cartridge and eluted with 3 ml of 10% acetonitrile, followed by 6 ml of distilled water. the separations were carried out using a mu Bondapak c18 column with a mobile phase comprising acetonitrile (60 ml), methanol (10 ml) and tetrahydrofuran (10 ml) in 15 mM phosphate buffer (920 ml) at pH 2.90. Separations were performed at 40 degrees C and detection was at 206 nm. Standard calibration plots of lisinopril in urine were linear (r > 0.998) and recovery was greater than 64%. The lowest quantifiable concentration was 0.5 micrograms/ml. Within-day and between-day imprecision (coefficient of variation) ranged from 2.51% to 9.26%, and inaccuracy was less than 8.3%.

Molecular mechanism for the relative binding affinity to the intestinal peptide carrier. Comparison of three ACE-inhibitors: enalapril, enalaprilat, and lisinopril

The affinity of three substrates for the intestinal peptide carrier is explained based on their three-dimensional (3D) structural data. The kinetic transport parameters of three ACE-inhibitors, enalapril, enalaprilat, and lisinopril, have been determined in an in vivo system using rat intestine. The observed kinetic transport parameters (+/- asymptotic standard error) of enalapril are: 0.81 (+/- 0.23) mM, 0.58 (+/- 0.37) mumol/h per cm2, and 0.56 (+/- 0.04) cm/h for the half-maximal transport concentration (KT), the maximal transport flux (Jmax) and the passive permeability constant (Pm). Enalaprilat was transported by passive diffusional with a Pm of 0.51 (+/- 0.04) cm/h. For lisinopril the kinetic transport parameters were 0.38 (+/- 0.19) mM, 0.12 (+/- 0.07) mumol/h per cm2, and 0.18 (+/- 0.02) cm/h for KT, Jmax, and Pm, respectively. The affinity of the ACE-inhibitors for the intestinal peptide carrier has been evaluated based on their ability to inhibit the transport rate of cephalexin. The inhibition constants (Ki) of enalapril, enalaprilat and lisinopril were 0.15, 0.28 and 0.39 mM, respectively. 3D structural analysis of lisinopril using molecular modelling techniques reveals that intramolecular hydrogen bond formation is responsible for decreased carrier affinity.