Efficacy and safety of lisinopril in older patients with essential hypertension

Control of energy balance by the brain renin-angiotensin system

The renin-angiotensin system (RAS) exists as a circulating hormone system but it is also used by various tissues of the body, including the brain, as a paracrine signaling mechanism. The local brain version of the RAS is mechanistically involved in fluid balance and blood pressure control, and there is growing appreciation for a role of the brain RAS in the control of energy balance. Here, we review major evidence for the control of energy balance by the brain RAS; outline the current understanding of the RAS components, targets, and mechanisms involved; and highlight some major questions that currently face the field.

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.

Effect of enalapril and nifedipine on orthostatic hypotension in older hypertensive patients

OBJECTIVE

To compare the effect of enalapril with long-acting nifedipine on orthostatic hypotension in older patients.

DESIGN

A prospective, double blinded, cross-over study.

SETTING

The outpatient clinic of a university hospital.

PARTICIPANTS

Thirty-nine patients aged 65 years or older with systolic blood pressure (SBP) of 140-190 mm Hg and diastolic blood pressure (DBP) of 90-110 mm Hg.

INTERVENTION

Enalapril 5-20 mg od or nifedipine 30-90 mg od for 8 weeks, followed by 4 weeks washout and cross-over for a second 8-week period.

MEASUREMENTS

Supine and standing 0-, 1-, and 5-minutes blood pressure was recorded before and at the end of each treatment period.

RESULTS

At baseline, SBP was 158.8 +/- 8.7 mm Hg, and DBP was 97.1 +/- 5.9 mm Hg. There was a decline in SBP of 6.1 +/- 2.7 mm Hg and 8.4 +/- 4.1 mm Hg after 1 and 5 minutes of standing, respectively. Both agents caused a significant decline in supine blood pressure. Enalapril: supine SBP 158.8 +/- 8.7 to 143 +/- 7.3 mm Hg; supine DBP 97.1 +/- 5.9 to 85.1 +/- 5.1 mm Hg (P = .0001). The drop in SBP after standing for 5 minutes was only 2.4 +/- 1.6 mm Hg with no change in diastolic values. A > or = 10 mm Hg drop in SBP was observed in only three patients, and no patient experienced a decline of 20 mm Hg or more. Nifedipine: supine SBP: 160.3 +/- 9 to 145.3 +/- 8.1 mm Hg; supine DBP: 96.3 +/- 5.7 to 86.3 +/- 5.8 (P = .0001). Nifedipine induced an orthostatic decline in SBP values; there was an 8.7 +/- 4.8 mm Hg difference between supine and 5 minutes standing values (P = .0005) without change in diastolic values. An orthostatic decline in SBP of > or = 10 mm Hg occurred in 13 patients, and there was a drop of > or = 20 mm Hg in six patients. The cross-over of enalapril and nifedipine reproduced the hypotensive effect and reversed the postural effect. (P = .0002 nifedipine vs enalapril)

CONCLUSIONS

Enalapril and nifedipine were equipotent in reducing supine blood pressure levels. Enalapril also reduced the number of orthostatic episodes significantly, whereas nifedipine aggravated this phenomenon.

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 in elderly patients with hypertension. Long term effects on renal and metabolic function

The efficacy and tolerability of lisinopril administered once daily were evaluated in a 12-week open study of 60 elderly patients aged between 65 and 85 years (mean 75 years) with essential hypertension. Mean sitting blood pressure was reduced from 190/106 +/- 6.3/1.3mm Hg (mean +/- SEM) at entry to 162/89 +/- 5.5/0.9 mm Hg after 12 weeks of treatment (p less than 0.001). There was no significant alteration in heart rate, and no occurrence of postural hypotension. The median daily dose of lisinopril was 20mg (range 5 to 40 mg) and only 4 patients required the addition of a diuretic. Mean glomerular filtration rate (GFR) at entry was 61.6 +/- 3.4 ml/min and was unchanged after 12 weeks of therapy. 25 patients continued to receive treatment for 1 year, and 20 of these completed 2 years of treatment. Control of blood pressure was maintained, and heart rate, biochemical parameters and GFR remained unaltered throughout the study. Renal function was preserved and renal blood flow, measured in a group of 14 patients, was significantly increased (p less than 0.025) at the end of the first year after treatment with lisinopril. Thus, in the elderly, lisinopril was well tolerated and highly effective in lowering blood pressure, and renal function was maintained.

Safety and tolerability of lisinopril in older hypertensive patients

The safety and tolerability of lisinopril have been assessed in 1,734 hypertensive patients treated with the agent in a number of clinical trials. Here we compare the clinical and laboratory adverse experiences in younger (under 55 years old) and older (at least 55 years old) patients treated with lisinopril monotherapy. The incidence of adverse experiences in these older patients was similar to that in the younger patients. A comparison also was made of clinical adverse experience data for older hypertensive patients treated either with lisinopril monotherapy or with various control agents (atenolol, metoprolol, and hydrochlorothiazide) in double-blind controlled studies. In these studies, the clinical adverse experience incidences and discontinuation percentages seen in the older patients treated with lisinopril were comparable to the data from the patients treated with the control agents. Thus, lisinopril is generally well-tolerated in older hypertensive patients, and should be considered a therapeutic option in the management of these patients.

Pathophysiology of hypertension in older patients

More than half of the United States population over 65 years of age has essential hypertension. In 1984, there were 10 million elderly hypertensive persons and this number will reach 25 million in the near future. These patients are at high risk for congestive heart failure, stroke, heart attack, and dissecting aneurysm. Successful reduction of blood pressure can lower these risks considerably, but rational treatment depends on understanding the complex pathophysiology of hypertension in older patients. In fact, treatment that does not take into account the combined effects of aging and hypertension on the cardiovascular system and the kidneys may do more harm than the hypertension itself. Among the prominent age-related cardiovascular changes are stiffening of the arterial tree, with or without a contribution from atherosclerosis. This reduces arterial compliance and increases afterload, resulting in the left-ventricular hypertrophy seen in old age and leading to a progressive rise in systolic pressure. There is considerable shrinkage of the kidneys, due primarily to loss of glomerular and tubular tissue in the cortex, along with sclerosis of the glomeruli and formation of tubular diverticula. Arteriolar changes lead to reduced renal blood flow, the shunting of blood around the glomeruli, and thus a reduction in glomerular filtration rate. Renal water and electrolyte excretion are changed, making homeostasis more difficult to maintain, and the renin-angiotensin system is altered, helping to blunt the kidneys' response to pressure changes. Essential hypertension superimposed on all the foregoing effects exacerbates them. Peripheral resistance is usually markedly elevated in older hypertensive persons, which increases afterload directly.(ABSTRACT TRUNCATED AT 250 WORDS)