Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2021 Publisher: Atnahs Pharma UK Limited, Sovereign House, Miles Gray Road, Basildon, Essex, SS14 3FR, United Kingdom
Pharmacotherapeutic group: Angiotensin-converting enzyme inhibitors
ATC code: C09AA03
Zestril is a peptidyl dipeptidase inhibitor. It inhibits the angiotensin-converting enzyme (ACE) that catalyses the conversion of angiotensin I to the vasoconstrictor peptide, angiotensin II. Angiotensin II also stimulates aldosterone secretion by the adrenal cortex. Inhibition of ACE results in decreased concentrations of angiotensin II which results in decreased vasopressor activity and reduced aldosterone secretion. The latter decrease may result in an increase in serum potassium concentration.
Whilst the mechanism through which lisinopril lowers blood pressure is believed to be primarily suppression of the reninangiotensin-aldosterone system, lisinopril is antihypertensive even in patients with low renin hypertension. ACE is identical to kininase II, an enzyme that degrades bradykinin. Whether increased levels of bradykinin, a potent vasodilatory peptide, play a role in the therapeutic effects of lisinopril remains to be elucidated.
The effect of Zestril on mortality and morbidity in heart failure has been studied by comparing a high dose (32.5 mg or 35 mg once daily) with a low dose (2.5 mg or 5 mg once daily). In a study of 3164 patients, with a median follow-up period of 46 months for surviving patients, high dose Zestril produced a 12% risk reduction in the combined endpoint of all-cause mortality and all-cause hospitalisation (p=0.002) and an 8% risk reduction in all-cause mortality and cardiovascular hospitalisation (p=0.036) compared with low dose. Risk reductions for all-cause mortality (8%; p=0.128) and cardiovascular mortality (10%; p=0.073) were observed. In a post-hoc analysis, the number of hospitalisations for heart failure was reduced by 24% (p=0.002) in patients treated with high-dose Zestril compared with low dose. Symptomatic benefits were similar in patients treated with high and low doses of Zestril.
The results of the study showed that the overall adverse event profiles for patients treated with high or low dose Zestril were similar in both nature and number. Predictable events resulting from ACE inhibition, such as hypotension or altered renal function, were manageable and rarely led to treatment withdrawal. Cough was less frequent in patients treated with high dose Zestril compared with low dose.
In the GISSI-3 trial, which used a 2x2 factorial design to compare the effects of Zestril and glyceryl trinitrate given alone or in combination for 6 weeks versus control in 19,394 patients who were administered the treatment within 24 hours of an acute myocardial infarction, Zestril produced a statistically significant risk reduction in mortality of 11% versus control (2p=0.03). The risk reduction with glyceryl trinitrate was not significant but the combination of Zestril and glyceryl trinitrate produced a significant risk reduction in mortality of 17% versus control (2p=0.02). In the sub-groups of elderly (age >70 years) and females, pre-defined as patients at high risk of mortality, significant benefit was observed for a combined endpoint of mortality and cardiac function. The combined endpoint for all patients, as well as the high-risk subgroups at 6 months, also showed significant benefit for those treated with Zestril or Zestril plus glyceryl trinitrate for 6 weeks, indicating a prevention effect for Zestril. As would be expected from any vasodilator treatment, increased incidences of hypotension and renal dysfunction were associated with Zestril treatment but these were not associated with a proportional increase in mortality.
In a double-blind, randomised, multicentre trial which compared Zestril with a calcium channel blocker in 335 hypertensive Type 2 diabetes mellitus subjects with incipient nephropathy characterised by microalbuminuria, Zestril 10 mg to 20 mg administered once daily for 12 months, reduced systolic/diastolic blood pressure by 13/10 mmHg and urinary albumin excretion rate by 40%. When compared with the calcium channel blocker, which produced a similar reduction in blood pressure, those treated with Zestril showed a significantly greater reduction in urinary albumin excretion rate, providing evidence that the ACE inhibitory action of Zestril reduced microalbuminuria by a direct mechanism on renal tissues in addition to its blood pressure-lowering effect.
Lisinopril treatment does not affect glycaemic control as shown by a lack of significant effect on levels of glycated haemoglobin (HbA1c).
Two large randomised, controlled trials (ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) and VA NEPHRON-D (The Veterans Affairs Nephropathy in Diabetes)) have examined the use of the combination of an ACE inhibitor with an angiotensin II receptor blocker.
ONTARGET was a study conducted in patients with a history of cardiovascular or cerebrovascular disease, or type 2 diabetes mellitus accompanied by evidence of end-organ damage. VA NEPHRON-D was a study in patients with type 2 diabetes mellitus and diabetic nephropathy.
These studies have shown no significant beneficial effect on renal and/or cardiovascular outcomes and mortality, while an increased risk of hyperkalaemia, acute kidney injury and/or hypotension as compared to monotherapy was observed. Given their similar pharmacodynamic properties, these results are also relevant for other ACE inhibitors and angiotensin II receptor blockers.
ACE inhibitors and angiotensin II receptor blockers should therefore not be used concomitantly in patients with diabetic nephropathy.
ALTITUDE (Aliskiren Trial in Type 2 Diabetes Using Cardiovascular and Renal Disease Endpoints) was a study designed to test the benefit of adding aliskiren to a standard therapy of an ACE inhibitor or an angiotensin II receptor blocker in patients with type 2 diabetes mellitus and chronic kidney disease, cardiovascular disease, or both. The study was terminated early because of an increased risk of adverse outcomes. Cardiovascular death and stroke were both numerically more frequent in the aliskiren group than in the placebo group and adverse events and serious adverse events of interest (hyperkalaemia, hypotension and renal dysfunction) were more frequently reported in the aliskiren group than in the placebo group.
In a clinical study involving 115 paediatric patients with hypertension, aged 6–16 years, patients who weighed less than 50 kg received either 0.625 mg, 2.5 mg or 20 mg of Zestril once a day, and patients who weighed 50 kg or more receivedeither 1.25 mg, 5 mg or 40 mg of Zestril once a day. At the end of 2 weeks, Zestril administered once daily lowered trough blood pressure in a dose-dependent manner with a consistent antihypertensive efficacy demonstrated at doses greater than 1.25 mg.
This effect was confirmed in a withdrawal phase, where the diastolic pressure rose by about 9 mmHg more in patients randomised to placebo than it did in patients who were randomised to remain on the middle and high doses of Zestril. The dose-dependent antihypertensive effect of Zestril was consistent across several demographic subgroups: age, Tanner stage, gender, and race.
Lisinopril is an orally active non-sulphydryl-containing ACE inhibitor.
Following oral administration of lisinopril, peak serum concentrations occur within about 7 hours, although there was a trend to a small delay in time taken to reach peak serum concentrations in acute myocardial infarction patients. Based on urinary recovery, the mean extent of absorption of lisinopril is approximately 25% with interpatient variability of 6-60% over the dose range studied (5-80 mg). The absolute bioavailability is reduced approximately 16% in patients with heart failure. Lisinopril absorption is not affected by the presence of food.
Lisinopril does not appear to be bound to serum proteins other than to circulating angiotensin-converting enzyme (ACE). Studies in rats indicate that lisinopril crosses the blood-brain barrier poorly.
Lisinopril does not undergo metabolism and is excreted entirely unchanged into the urine. On multiple dosing, lisinopril has an effective half-life of accumulation of 12.6 hours. The clearance of lisinopril in healthy subjects is approximately 50 ml/min. Declining serum concentrations exhibit a prolonged terminal phase, which does not contribute to drug accumulation. This terminal phase probably represents saturable binding to ACE and is not proportional to dose.
Impairment of hepatic function in cirrhotic patients resulted in a decrease in lisinopril absorption (about 30% as determined by urinary recovery), but an increase in exposure (approximately 50%) compared to healthy subjects due to decreased clearance.
Impaired renal function decreases elimination of lisinopril, which is excreted via the kidneys, but this decrease becomes clinically important only when the glomerular filtration rate is below 30 ml/min. In mild to moderate renal impairment (creatinine clearance 30-80 ml/min), mean AUC was increased by 13% only, while a 4.5-fold increase in mean AUC was observed in severe renal impairment (creatinine clearance 5-30 ml/min).
Lisinopril can be removed by dialysis. During 4 hours of haemodialysis, plasma lisinopril concentrations decreased on average by 60%, with a dialysis clearance between 40 and 55 ml/min.
Patients with heart failure have a greater exposure of lisinopril when compared to healthy subjects (an increase in AUC on average of 125%), but based on the urinary recovery of lisinopril, there is reduced absorption of approximately 16% compared to healthy subjects.
The pharmacokinetic profile of lisinopril was studied in 29 paediatric hypertensive patients, aged between 6 and 16 years, with a GFR above 30 ml/min/1.73m². After doses of 0.1 to 0.2 mg/kg, steady state peak plasma concentrations of lisinopril occurred within 6 hours, and the extent of absorption based on urinary recovery was about 28%. These values are similar to those obtained previously in adults.
AUC and Cmax values in children in this study were consistent with those observed in adults.
Elderly have higher blood levels and higher values for the area under the plasma concentration-time curve (increased approximately 60%) compared with younger subjects.
Preclinical data reveal no special hazard for humans based on conventional studies of general pharmacology, repeated dose toxicity, genotoxicity, and carcinogenic potential. Angiotensin-converting enzyme inhibitors, as a class, have been shown to induce adverse effects on the late foetal development, resulting in foetal death and congenital effects, in particular affecting the skull. Foetotoxicity, intrauterine growth retardation and patent ductus arteriosus have also been reported. These developmental anomalies are thought to be partly due to a direct action of ACE inhibitors on the foetal renin-angiotensin system and partly due to ischaemia resulting from maternal hypotension and decreases in foetal- placental blood flow and oxygen/nutrients delivery to the foetus.
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