Hemodynamic and hormonal effects of quinaprilat in patients with congestive heart failure

Quinaprilat: a review of its pharmacokinetics, pharmacodynamics, toxicological data and clinical application

BACKGROUND

Quinaprilat is an ACE inhibitor for intravenous use especially in patients with arterial hypertension or chronic heart failure. In contrast to the oral prodrug quinapril, it has not been approved for clinical application.

OBJECTIVE

In this review, the pharmacokinetic and pharmacodynamic profile of quinaprilat as well as toxicological data and results of preclinical and clinical studies are summarized.

METHODS

In a PubMed search for the terms "quinaprilat" and "quinapril", literature relevant for this review was selected.

RESULTS

Quinaprilat is a potent nonsulfhydryl selective ACE inhibitor with a short elimination half-life of 2 - 3 h, but due to slow dissociation from tissue ACE, once daily dosing is sufficient for effective ACE inhibition. Quinaprilat is excreted mainly in urine. In long-term animal studies, quinaprilat was not teratogenic, mutagenic or carcinogenic. However, due to the risk of fetal and neonatal morbidity and death, it should not be administrated in pregnancy. Quinaprilat is characterized by an excellent safety profile; adverse events occur infrequently and are rarely serious.

CONCLUSION

Quinaprilat is an attractive ACE inhibitor, which potently inhibits tissue ACE.

Haemodynamic effects of intravenous quinaprilat in comparison to sodium nitroprusside in patients with chronic heart failure

We compared the haemodynamic effects of intravenous boluses of the ACE inhibitor quinaprilat with an intravenous infusion of sodium nitroprusside in 23 patients with chronic heart failure (NYHA Class III or IV). At the highest drug doses, sodium nitroprusside significantly increased stroke volume index (+6.63 ml/m(2), p=0.045), whereas quinaprilat induced only a minor increase (+1.79 ml/m(2), n.s.).

Angiotensin antagonism in patients with heart failure: ACE inhibitors, angiotensin receptor antagonists or both?

Chronic heart failure (CHF) is a major cause of morbidity and mortality in western society. It is now widely accepted that the renin-angiotensin-aldosterone system (RAAS) and, in particular, angiotensin II (A-II) play a key role in the pathophysiology of CHF. Large-scale clinical trials have demonstrated that inhibitors of angiotensin-converting enzyme (ACE), the principal enzyme responsible for A-II production, improve symptoms and survival in patients with CHF. This enzyme is also responsible for the breakdown of the vasodilator hormone bradykinin. Administration of ACE inhibitors is associated with increased plasma bradykinin levels and this is thought to contribute to the vascular changes associated with ACE inhibitor therapy. However, RAAS inhibition with ACE inhibitors remains incomplete because ACE inhibitors do not block the non-ACE-mediated conversion of angiotensin I to A-II. Angiotensin receptor antagonists (angiotensin receptor blockers; ARBs) antagonize the action of A-II at the A-II type 1 (AT(1)) receptor, whilst allowing the potentially beneficial actions of A-II mediated via the A-II type 2 (AT(2)) receptor. Evidence that the clinical benefit demonstrated with ACE inhibitors in patients with CHF may extend to ARBs has only emerged recently. Combination therapy with both an ACE inhibitor and an ARB has a number of potential advantages and has been investigated in several large-scale clinical trials recently. In patients with CHF, first-line therapy should include an ACE inhibitor and a beta-adrenoceptor antagonist. The addition of an ARB provides symptomatic relief but has not been shown to improve survival. Where an ACE inhibitor is not tolerated, treatment with an ARB would seem an appropriate alternative. There is insufficient data to support the routine use of ARBs as first-line therapy in the management of CHF.

Valsartan in heart failure patients previously untreated with an ACE inhibitor

OBJECTIVE

To evaluate the effect on cardiac hemodynamic parameters of valsartan in patients with chronic stable congestive heart failure previously untreated with ACE inhibitors.

METHODS

After a 2 to 4 week run-in period, 116 adult outpatients were randomized to receive valsartan 40, 80 or 160 mg twice daily, the ACE inhibitor lisinopril 5/10 mg once daily, or placebo. At baseline and after 28 days of treatment, cardiac hemodynamic parameters were measured. Tolerability was assessed by adverse events and by any changes in systolic or diastolic blood pressure, body weight, heart rate, and routine laboratory parameters.

RESULTS

For the 12 hour time point (trough), all doses of valsartan reduced mean pulmonary capillary wedge pressure (statistically significant for valsartan 40 mg and 160 mg), decreased systemic vascular resistance (statistically significant for all three valsartan doses and for lisinopril at peak and trough), and increased cardiac output (statistically significant for all three valsartan doses at peak, and for 80 and 160 mg at trough). There were no clinically relevant effects on any safety parameters.

CONCLUSIONS

Valsartan has beneficial effects on cardiac hemodynamics, and is generally well tolerated in patients with congestive heart failure not taking ACE inhibitors.