Intravenous captopril in congestive heart failure

Hemodynamic and neurohumoral effects of intravenous captopril were studied in ten patients with severe chronic congestive heart failure (NYHA Functional Class III and IV). Incremental bolus doses of captopril, titrated to a maximum cumulative dose of 15 mg, were given at 10-minute intervals. Systemic arterial pressure, mean pulmonary capillary wedge pressure, systemic vascular resistance, mean pulmonary artery pressure, and heart rate decreased (P less than .05). Cardiac index and stroke volume index increased (P less than .05). Maximum hemodynamic effects occurred after cumulative doses of 7 mg and were seen within 30 minutes after initiation of therapy; responses persisted for 30-90 minutes after the last dose. Plasma renin activity increased, and plasma atrial natriuretic factor concentration decreased. No adverse effects were observed with the use of intravenous captopril. Thus, intravenous captopril produces rapid and favorable hemodynamic improvement in advanced heart failure patients.     

The effect of captopril on pharmacokinetics of digoxin in patients with mild congestive heart failure.

The effect of captopril on steady-state pharmacokinetics of digoxin was studied in 12 patients with mild congestive heart failure (CHF; New York Heart Association functional class 1 or 2). Serum and urine digoxin concentrations were determined before and after a repeated administration of captopril in the patients on chronic digoxin therapy. The patients were taking digoxin, 0.25-0.375 mg/day, once daily, and were concurrently administered captopril, 37.5 mg/day, three times daily, for seven days. Peak serum concentration of digoxin (SCD) before and after captopril was 2.1 +/- 0.2, mean +/- SEM, and 2.0 +/- 0.1 ng/ml; the time to peak was 1.1 +/- 0.2 and 1.8 +/- 0.3 h; the terminal half-life (t1/2 alpha) was 10.9 +/- 1.0 and 8.7 +/- 0.9 h, and the area under the concentration-time curve to 24 h was 26.9 +/- 2.4 and 27.6 +/- 2.0 ng.h/ml. There was no significant difference between patients without and with captopril in SCD and its pharmacokinetic parameters. Renal digoxin clearance and creatinine clearance also showed no significant difference. After an administration of captopril, angiotensin-converting-enzyme (ACE) activity was well suppressed. These results suggest that captopril does not increase SCD in patients with CHF, and effectively suppresses ACE activity. Thus, modification in the dosage regimen of digoxin may be unnecessary in the case of coadministration with captopril.     

Oxaprozin pharmacokinetics in patients with congestive heart failure

12 patients aged 26-71 years with stable, compensated congestive heart failure (CHF) and 12 healthy controls matched for age, sex, height, weight, and serum albumin, received a 1200-mg oral dose of the nonsteroidal antiinflammatory agent 4,5-diphenyl-2-oxazolepropionic acid (oxaprozin). Serum oxaprozin levels were measured by high pressure liquid chromatography during the next 14 days. Oxaprozin elimination half-life was not different between controls and CHF patients (63 vs 69 h), but peak serum levels were lower (79 vs 63 micrograms/ml, p less than 0.01), apparent volume of distribution was larger (0.22 vs 0.29 l/kg, p less than 0.05) and clearance tended to be higher, although not significantly so, (0.042 vs 0.053 ml/min/kg) in CHF patients. These differences might have been due to reduced serum protein binding (increased free fraction) in CHF patients (0.25 vs 0.44% unbound, p less than 0.1). After correction for individual values of free fraction, groups did not differ in peak free oxaprozin serum levels (0.20 vs 0.26 micrograms/ml), unbound volume of distribution (92 vs 83 l/kg), or unbound clearance (17.5 vs 15.0 ml/min/kg). Thus protein binding of oxaprozin in the present study was reduced in CHF due either to the underlying disease or to the concurrent medications. This in turn caused reciprocal reduction in total (free plus bound) oxaprozin levels and elevated estimates of volume of distribution and clearance. Although protein binding is altered, CHF causes no significant alteration in distribution of free oxaprozin nor free clearance of oxaprozin, which is accomplished by a combination of oxidation and conjugation.     

The pharmacokinetics of midazolam in patients with congestive heart failure.

The disposition of midazolam was investigated in six patients with congestive heart failure (CHF) and six age- and weight-matched healthy subjects by administering two single doses of the drug (3.75 mg i.v. and 7.5 mg p.o.) separated by 1 week. Serial blood samples were collected for 24 h after each dose and plasma was assayed for midazolam by GC-MS. In the CHF patients, the elimination half-life was prolonged (4 to 4.5 vs less than 3 h), the systemic clearance was lowered (376 vs 551 ml min-1) and the peak plasma drug concentration after the p.o. dose was higher (76 vs 42 ng ml-1). The systemic availability (45 vs 41%), the steady state volume of distribution (111 vs 108 l) and the time of peak plasma drug concentration after the p.o. dose (0.9 vs 0.9 h) were unchanged. The predominant effect of CHF was on the clearance of midazolam which was decreased by 30%. The drug was well tolerated and did not cause any adverse effects.     

Altered prazosin pharmacokinetics in congestive heart failure

Summary The pharmacokinetics of prazosin (Minipress^®) were studied in nine patients with NYHA Class 3 or 4 congestive heart failure and in five healthy controls. After a single 5 mg oral dose, plasma concentrations of prazosin, as reflected in the area under the plasma concentration-time curve (AUC) and prazosin plasma half-life, were approximately double in the patients in comparison to the control group. Reduction in hepatic blood flow, altered gastrointestinal absorption of the drug or diminished intrinsic hepatic metabolic activity in the patient group may have contributed to the observed changes in prazosin disposition. The finding of higher prazosin plasma concentrations in patients with refractory heart failure demonstrates the need for close monitoring of these individuals following administration of the drug in the treatment of chronic congestive heart failure.Sponsored by the National Institute of General Medical Sciences Training Grant GM 07546 and by a grant from Pfizer Corporation     

Oral enoximone pharmacokinetics in patients with congestive heart failure

The pharmacokinetics of enoximone and its sulfoxide metabolite were determined following administration of a single oral dose of 1 or 2 mg/kg in seven patients with congestive heart failure, and in two normal volunteers following a single 75-mg capsule, and were compared to those published previously. Plasma concentrations of the metabolite were higher than enoximone, and their terminal slopes were parallel. Enoximone and enoximone sulfoxide plasma concentration-time data were fitted to a simple model that included a lag time. Absorption half-lives in patinets and normal volunteers averaged 17 minutes; the elimination half-life of enoximone in patients averaged 2.9 hours, and was slightly prolonged as compared with normal volunteers. The elimination half-life of enoximone sulfoxide averaged 17 minutes in patients and normal volunteers, and was considerably shorter than that reported in other studies. The oral clearance of enoximone in patients averaged 99 L/hr, and was lower than that observed in normal volunteers. The ratio of the area under the plasma concentration time curve of enoximone sulfoxide to enoximone averaged 4.7 in patients, and was similar to that observed in normal subjects. Enoximone oral clearance and the ratio of metabolite to parent were related to liver blood flow (determined by indocyanine green). Enoximone is 65% bound to albumin, which accounts for most of the drug bound to human plasma protein.     

The pharmacokinetics of lisinopril in hospitalized patients with congestive heart failure.

1. The pharmacokinetics of the angiotensin converting enzyme inhibitor, lisinopril, were studied in an open, randomized, balanced, two-period, crossover design in 12 in-patients with stable, chronic congestive heart failure (CHF). 2. To evaluate the pharmacokinetics of lisinopril in CHF, lisinopril was administered orally (10 mg) and intravenously (5 mg) in each patient. Each dose was followed by a 72 h period with frequent blood sampling and fractional urine collections for radioimmunoassay of lisinopril. 3. Mean urinary recovery of lisinopril was 15 and 88% following oral and intravenous administration, respectively; absorption/bioavailability of lisinopril based on urinary recovery ratios was 16%, less than that found in normal subjects. 4. Serum concentrations of lisinopril following intravenous administration were higher in this study than those previously observed in normal subjects. 5. The results of this study suggest a reduced absorption of lisinopril in CHF and altered disposition, possibly associated with age as well as the disease state.     

The pharmacokinetics of enalapril in hospitalized patients with congestive heart failure.

The pharmacokinetics of the converting enzyme inhibitor, enalapril, were studied in an open, randomized, balanced crossover design in 12 hospitalized patients with stable, chronic congestive heart failure (CHF). Enalapril maleate is a prodrug requiring in vivo hepatic esterolysis to yield the active diacid inhibitor enalaprilat. CHF results in changes in regional blood flow that may affect the gastrointestinal absorption, hepatic hydrolysis and renal excretion of enalapril and enalaprilat. In order to evaluate the pharmacokinetics of enalapril in CHF, the following treatments were given: enalapril maleate 10 mg orally, enalapril maleate 5 mg intravenously and enalaprilat 5 mg intravenously. Each dose was followed by a 72 h period with frequent blood sampling and fractionated urine collection for the radioimmunoassay of enalaprilat, before and after sample hydrolysis. Mean absorption for the oral dose was 69%, hydrolysis 55%, bioavailability 38%, urinary recovery 77% and estimated first-pass effect 10%. The results were compared with available data in normal subjects. After oral administration of 10 mg enalapril maleate, the extent of absorption, the degree of hydrolysis and the bioavailability in CHF patients appear to be similar to those in normals with differences less than 10%. The rate of absorption and hydrolysis appear to be slightly slower in CHF. The serum concentrations of enalaprilat were consistently greater in CHF and maximal concentrations were reached at 6 h in CHF as compared to 4 h in normal subjects. We conclude that the presence of CHF does not appreciably alter the pharmacokinetic behaviour of enalapril. The observed differences may be associated with age as well as the disease state.     

Population pharmacokinetics of levosimendan in patients with congestive heart failure

AIMS: The aim of this study was to characterize the population pharmacokinetics of levosimendan in patients with heart failure (NYHA grades III and IV) and its relationship to demographic factors, disease severity and concomitant use of digoxin and beta-blocking agents. METHODS: Data from two efficacy studies with levosimendan administered by intravenous infusion were combined (190 patients in total). The data were analysed using a nonlinear mixed-effects modelling approach as implemented in the NONMEM program. The model development was done in three sequential steps. First the best structural model was determined (e.g. a one-, two- or three-compartment pharmacokinetic model). This was followed by the identification and incorporation of important covariates into the model. Lastly the stochastic part of the model was refined. RESULTS: A two-compartment model best described levosimendan pharmacokinetics. Clearance and the central volume of distribution were found to increase linearly with bodyweight. No other covariates, including concomitant use of digoxin and beta-blocking agents, influenced the pharmacokinetics. In the final model, a 76-kg patient was estimated to have a clearance +/- s.e. of 13.3 +/- 0.4 l h-1 and a central volume of distribution of 16.8 +/- 0.79 l. The interindividual variability was estimated to be 39% and 60% for clearance and central volume of distribution, respectively. Weight changed clearance by 1.5% [95% confidence interval (CI) 0.9%, 2.1%] and the central volume of distribution by 0.9% (95% CI 0.5%, 1.3%) per kg. CONCLUSIONS: The population pharmacokinetics parameters of levosimendan in this patient group were comparable to those obtained by traditional methods in healthy volunteers and patients with mild heart failure. Bodyweight influenced the clearance and the central volume of distribution, which in practice is accounted for by weight adjusting doses. None of the other covariates, including digoxin and beta-blocking agents, significantly influenced the pharmacokinetics of levosimendan.     

Pharmacodynamics and pharmacokinetics of nifedipine in patients with congestive heart failure

Twenty-seven cases of congestive heart failure (CHF) were treated with nifedipine (Nif) 20 mg po. Significant improvements in resting hemodynamics were found in 22 cases. The higher the basal systemic vascular resistance (SVR) and pulmonary artery end diastolic pressure (PAEDP) were, the greater the magnitudes of reduction found (r = 0.84 and 0.77, P less than 0.01, respectively). Exercise hemodynamic investigation showed that Nif led to a lowering of SVR, PAEDP and pulmonary vascular resistance (PVR), with increases in SV and concentration of 5-10 ng/ml, with a maximum being observed at the concentration of 20 ng/ml. No further vasodilation was found when the plasma concentration exceeded 20 ng/ml. No remarkable deviations from the normal ranges of Nif pharmacokinetics were found in CHF patients. The plasma norepinephrine level decreased markedly 2 and 7 h after Nif. Thus, it is concluded that oral Nif is beneficial in severe CHF patients having low cardiac output and high SVR.     

卡托普利与倍他乐克联合治疗充血性心力衰竭的临床疗效评价

目的：评价常规强心、利尿基础上，卡托普利、倍他乐克治疗充血性心力衰竭的疗效。方法：选择慢性充血性心力衰竭（CHF）64例，随机分组：观察组（n=32)，常规治疗基础上，加用卡托普利、倍他乐克，疗程观察4－6wk。对照组（n=32)为常规观察组。结果：观察组心功能改善I－Ⅱ级以上为有效，按照YNHA心功能分级，28例有效，占87．5％，对照组19例有效，占59．4％。观察组的收缩压、舒张压、心率较对照组明显下降（P＜0．01），左室射血分数上升（P＜0．01）。结论：强心、利尿基础上加用卡托普利和倍他乐克治疗，能有效地改善CHF患的心功能，疗效优于常规治疗。     

The effects of captopril on serum digoxin levels in patients with severe congestive heart failure

The effects of captopril on serum digoxin concentrations were studied in 8 patients with severe (NYHA Class IV) congestive heart failure. Serum digoxin concentrations were determined before and after the administration of captopril for 1 week in patients on chronic digoxin therapy. Each patient who was taking 0.25 mg of digoxin PO q.d., was administered 12.5 mg of captopril PO t.i.d. for 7 days. The peak serum concentration of digoxin (Cmax) before and after (on Days 0 and 7) captopril administration was 1.7+/-0.2 ng/ml and 2.7+/-0.2 ng/ml, the time to peak (tmax) was 2.4+/-0.5 h and 1.3+/-0.2 h, and the area under the 24-hour digoxin concentration-time curve (AUC0-24h) was 30.0+/-1.5 ng x h/ml and 41.7+/-3.4 ng x h/ml, respectively. While captopril caused a significant increase in peak serum concentration and the area under the digoxin concentration-time curve, it decreased the time to digoxin peak (p = 0.01, p = 0.04, p = 0.01, respectively). No patient developed evidence of digoxin toxicity. Concomitant administration of captopril with digoxin increases serum digoxin concentration in patients with severe congestive heart failure.     

The pharmacokinetics of quinapril and quinaprilat in patients with congestive heart failure.

The pharmacokinetics of quinapril and its active metabolite quinaprilat were studied in 12 patients with congestive heart failure (CHF) after multiple oral doses of 10 mg quinapril twice daily. Six patients had an ejection fraction of < 35% and six had an ejection fraction between 35%-50%. Increases in the apparent elimination half-life and in AUC(0, 12h) values of quinaprilat were associated with smaller ejection fractions, decreased creatinine clearance, and increased patient age. Comparison with data from age-matched controls having comparable renal function suggests that creatinine clearance is the major determinant of quinaprilat clearance. CHF per se appears to have minimal effect. Dosing of quinapril in patients with CHF should be based on their renal function.     

卡托普利、倍他乐克联合治疗慢性充血心力衰竭的临床观察

目的　观察卡托普利、倍他乐克联合治疗对慢性充血性心力衰竭 (CHF)病人的心功能、心率、心胸比及左室射血分数 (LVEF)的影响。方法　 62例CHF病人随机分为两组 ,对照组 30例采用地高辛利尿剂、消心痛等治疗 ,治疗组 32例采用倍他乐克、卡托普利、地高辛、利尿剂治疗。治疗 1 2周。结果　治疗组 ,心率减慢、心胸比率缩小 ,LVEF提高 ,与治疗前相比差异有显著意义 (P <0 0 1 )。而对照组治疗后心率减慢 ,心胸比率缩小 ,LVEF提高 ,但与治疗前相比差异无显著意义 (P >0 0 5)。结论　卡托普利、倍他乐克联合治疗CHF ,可明显使病人心率减慢 ,心胸比率缩小 ,LVEF提高     

氯沙坦联合卡托普利治疗心衰疗效的研究

目的:探讨氯沙坦联合卡托普利治疗充血性心力衰竭(CHF)的血流动力学和神经内分泌改变的临床意义。方法:60例充血性心力衰竭患者在维持原强心、利尿、扩血管等基础上随机分为卡托普利组、氯沙坦组和氯沙坦联合卡托普利组共3组,对照组25例为健康体检者。治疗前后测定血管紧张素Ⅱ(AⅡ)、ET、一氧化氮(NO)、射血分数(EF)和右室舒张末期容积(LVEDV)。结果:3组患者在治疗前AⅡ、ET增高,NO降低,较对照组差异有显著性(P<0.01)。治疗后各组自身对照,AⅡ、ET和LVEDV降低,EFF和NO增加,差异亦有显著性(P<0.0l)。联合组较单用组其AⅡ、ET和LVEDV降低与EF和NO增加差异有显著性(P<0.05) ,两组单用组比较差异不显著(P>0.05)。结论:CHF是发生了神经内分泌紊乱,单用卡托普利或氯沙坦能改善神经内分泌紊乱和血流动力学,但卡托普利与氯沙坦联合应用疗效优于单用     

Aldosterone and prolactin responsiveness after prolonged treatment of congestive heart failure with captopril

After long-term captopril treatment, an inappropriate increase in aldosterone levels has been observed in hypertensive patients. It is not known, whether a similar change would occur in patients with severe congestive heart failure, and whether it is due to a decrease in endogenous dopaminergic inhibition of aldosterone secretion or to aldosterone stimulation by ACTH or an ACTH-related peptide. Therefore, the aldosterone and prolactin responses to metoclopramide have been studied in 10 patients with severe congestive heart failure (NYHA Class III or IV) after 6 months of captopril treatment, before and 11 h after pretreatment with dexamethasone. 7 placebo-treated patients served as double-blind controls. In captopril-treated patients, the supine aldosterone levels exceeded the normal range and were as high as in placebo-treated patients. The responsiveness of aldosterone and prolactin to metoclopramide was not influenced by captopril. Only in the placebo group were the aldosterone levels decreased by dexamethasone. Captopril increased plasma renin activity and serum potassium, and decreased supine epinephrine and norepinephrine and serum sodium. Thus, previous reports of inappropriately high aldosterone levels after long-term captopril treatment were confirmed in patients with severe congestive heart failure. It is concluded that increased aldosterone is due neither to a decrease in endogenous dopaminergic inhibition nor to dexamethasone-suppressible stimulation of aldosterone secretion.     

A pharmacokinetic and pharmacodynamic evaluation of buffered sublingual captopril in patients with congestive heart failure

Objective: The pharmacokinetics and pharmacodynamics of buffered sublingual captopril were assessed in patients with congestive heart failure (CHF). Methods: The study was carried out in a randomised single-blind cross-over fashion (n=6, 4 males and 2 females) and involved two study days, at least 7 days apart. Baseline measurements were carried out for plasma renin activity (PRA), blood pressure (B.P.) and heart rate (H.R.). Captopril (12.5 mg) was administered sublingually with dibasic potassium phosphate which maintained salivary pH at 7, or perorally with 100 ml of water. Further B.P., H.R. measurements and venous blood samples were taken over a 3 hour period post-drug administration. Blood samples were analysed for captopril and PRA levels. Results: t_max after buffered sublingual administration of captopril, which ranged from 40–60 min (median=40 min), was significantly shorter than after peroral administration (range 60–120 min, median=90 min). C_max was slightly greater after buffered sublingual than after peroral administration with mean values of 108.2 vs. 94.0 ng·ml^–1. AUC values were similar after both routes of administration. Systolic and diastolic B.P. vs. time profiles for each administration method were significantly different i.e. sublingual administration produced an earlier reduction in B.P., however, HR did not differ significantly between the two routes. Conclusion: The data indicate that this novel administration method of captopril leads to an increased rate, but an unchanged extent of captopril absorption, suggesting a modest therapeutic advantage with the use of buffered sublingual captopril if a rapid reduction in blood pressure is required.     

Effect of congestive heart failure on the pharmacokinetics of cibenzoline

Six patients with chronic congestive heart failure (CHF) (New York Heart Association functional class II or III) and five healthy subjects completed this study designed to determine if CHF alters the pharmacokinetics and absolute bioavailability of cibenzoline when compared with healthy subjects. Each subject or patient was administered a one-hour intravenous infusion of 80 mg of 15N2-cibenzoline and simultaneously received an 80-mg oral dose of cibenzoline that allowed for analytic separation of each route of administration. Resulting plasma concentration-time profiles and urinary excretion rate data were used to determine pharmacokinetic parameters for cibenzoline. There were no statistically significant differences in any pharmacokinetic parameter between patients with CHF and healthy subjects. The absolute bioavailability ranged from 74% to 97% in those with CHF. The volume of distribution following the intravenous dose ranged from 3.4 to 6.1 L/kg, and plasma clearance ranged from 245 to 642 mL/min, with an apparent elimination half-life of approximately ten hours. Approximately 60% of the dose was recovered in the urine. Overall, the pharmacokinetics of cibenzoline in patients with chronic CHF do not differ from those observed in healthy subjects.     

Clinical pharmacokinetics and therapeutic use of hydralazine in congestive heart failure

Hydralazine (1-hydrazinophthalazine) has been used extensively in the treatment of hypertension and congestive heart failure and produces arteriolar vasodilation, in part, mediated by prostaglandins. Its associated reflex baroreceptor-mediated responses of tachycardia and increased ejection velocity are attenuated in congestive heart failure. A direct inotropic effect has been attributed to the drug. Pharmacokinetic data indicate hydralazine is absorbed well from the gastrointestinal tract, and has an extensive and complex metabolism depending on acetylator status: slow acetylators undergo primary oxidative metabolism, while rapid acetylators are acetylated. Half-lives, clearances and bioavailability of the drug are not significantly altered in congestive heart failure compared with hypertensive patients. A wide range of dosages in heart failure has been noted (150 to 3000 mg/24h), and may related to a saturation of the first-pass effect. Hydralazine improves haemodynamics in the short term in patients with increased peripheral vascular resistance, and has variable effects on pulmonary capillary wedge and left ventricular filling pressures. Prediction of the short term clinical response is difficult and appears to be independent of pharmacokinetics. A meta analysis did not demonstrate long term efficacy of hydralazine alone in heart failure, but combination therapy with nitrates has been shown to improve survival and exercise performance in patients with mild to moderate heart failure. Side effects are common and are dependent on dose, duration and acetylator status.