'First dose' hypotension and venodilatation

Drug-Related Orthostatic Hypotension: Beyond Anti-Hypertensive Medications

Orthostatic hypotension (OH) is an abnormal blood pressure response to standing, which is associated with an increased risk of adverse outcomes such as syncope, falls, cognitive impairment, and mortality. Medical therapy is one the most common causes of OH, since numerous cardiovascular and psychoactive medications may interfere with the blood pressure response to standing, leading to drug-related OH. Additionally, hypotensive medications frequently overlap with other OH risk factors (e.g., advanced age, neurogenic autonomic dysfunction, and comorbidities), thus increasing the risk of symptoms and complications. Consequently, a medication review is recommended as a first-line approach in the diagnostic and therapeutic work-up of OH, with a view to minimizing the risk of drug-related orthostatic blood pressure impairment. If symptoms persist after the review of hypotensive medications, despite adherence to non-pharmacological interventions, specific drug treatment for OH can be considered. In this narrative review we present an overview of drugs acting on the cardiovascular and central nervous system that may potentially impair the orthostatic blood pressure response and we provide practical suggestions that may be helpful to guide medical therapy optimization in patients with OH. In addition, we summarize the available strategies for drug treatment of OH in patients with persistent symptoms despite non-pharmacological interventions.

ACE inhibitors and the risk of fractures: a meta-analysis of observational studies

A meta-analysis was conducted to evaluate the effect of treatment with angiotensin-converting enzyme inhibitors on the risk of fractures. All the included articleswere retrieved from MEDLINE, EMBASE and the Cochrane Database. Trial eligibility and methodological quality were assessed before data extraction. Relative risk (RR) with corresponding 95% confidence intervals (95% CI) were used to assess the effect. Six case-control studies with11,387,668 participants met the inclusion criteria and were included in the meta-analysis. A small but significant risk effect on fractures was shown in the overall analysis of angiotensin-converting enzyme inhibitor users compared with nonusers (Pooled RR 1.27; 95% CI 1.01-1.60), although a relatively high heterogeneity was found across studies. In the stratified analysis, therewas no statistically significant association in the subgroups of hip fracture (Pooled RR 1.14; 95% CI 0.73-1.76) and the study quality (Pooled RR 1.13; 95% CI 0.89-1.44), while the over 65-year-old angiotensin-converting enzyme inhibitor users showed a stronger risk effect on fractures (Pooled RR 2.06; 95% CI 1.53-3.17). Moreover, age was found to be contributed a large part of the high heterogeneity across the included studies. This study demonstrated that the use of angiotensin-converting enzyme inhibitors might have a small but significant risk effect on fractures, especially for the over 65-year-old users. These results should be interpreted with caution as the relatively high heterogeneity across studies. Additional multiple observational studies and high quality data from randomized controlled trials are needed to confirm these findings.

The risk of falls on initiation of antihypertensive drugs in the elderly

SUMMARY

Antihypertensive drugs are associated with an immediate increased falls risk in elderly patients which was significant during the first 14 days after receiving a thiazide diuretic, angiotensin-converting enzyme inhibitor, angiotensin II receptor blocker, calcium channel blocker, or beta-adrenergic blocker. Fall prevention strategies during this period may prevent fall-related injuries.

INTRODUCTION

The purpose of this study is to evaluate if initiation of the common antihypertensive drugs is associated with the occurrence of falls.

METHODS

This population-based self-controlled case series study used healthcare administrative databases to identify new users of antihypertensive drugs in the elderly aged 66 and older living in Ontario, Canada who suffered a fall from April 1, 2000 to March 31, 2009. The risk period was the first 45 days following antihypertensive therapy initiation, further subdivided into 0-14 and 15-44 days with control periods before and after treatment in a 450-day observation period. We calculated the relative incidence (incidence rate ratio, IRR), defined as the rate of falls in the risk period compared to falls rate in the control periods.

RESULTS

Of the 543,572 new users of antihypertensive drugs among community-dwelling elderly, 8,893 experienced an injurious fall that required hospital care during the observation period. New users had a 69 % increased risk of having an injurious fall during the first 45 days following antihypertensive treatment (IRR = 1.69; 95 % CI, 1.57-1.81). This finding was consistent for thiazide diuretics, angiotensin-converting enzyme inhibitors, calcium channel blockers, and beta-adrenergic blockers but not angiotensin II receptor antagonists. There was also an increased falls risk during the first 14 days of antihypertensive drug initiation (IRR = 1.94; 95 % CI, 1.75-2.16), which was consistent for all antihypertensive drug classes.

CONCLUSIONS

This study suggests that initiation of antihypertensive drugs is a risk factor for falls in the elderly. Fall prevention strategies during this period may reduce injuries.

Acute blood pressure response to trandolapril and captopril in patients with left ventricular dysfunction after acute myocardial infarction

OBJECTIVE

Our purpose was to compare the blood pressure response to short-term treatment with captopril or trandolapril in patients with left ventricular (LV) dysfunction after acute myocardial infarction (AMI).

METHODS

A multicenter, randomized, double-blind, double-dummy, parallel group study was performed. Treatment was initiated 3 to 10 days after the onset of symptoms. On day 1, patients received a single dose of captopril 6.25 mg, trandolapril 0.5 mg, or placebo in the morning. Treatment was then titrated upward over the next 5 days. Blood pressure was monitored with an automated device for the first 12 hours after dosing on day 1. Conventional blood pressure measurements were performed throughout the study.

RESULTS

Of 205 patients treated in the study, 193 patients were evaluated for first-dose effects. In the captopril group, the maximum decrease in blood pressure occurred after 2 hours, and the magnitude of this decrease was significantly greater than in the other 2 groups: 8.8 +/- 12/6.3 +/- 8 mm Hg (captopril) versus 5.4 +/- 10/3.1 +/- 8 mm Hg (trandolapril) versus 2.4 +/- 9/1.4 +/- 7 mm Hg (placebo) (P <.01). In the trandolapril group, the maximum decrease occurred after 7 hours and the magnitude of this effect was similar in all 3 groups: 5.9 +/- 11/3.6 +/- 8 mm Hg (trandolapril) versus 4.3 +/- 10/3.5 +/- 8 mm Hg (captopril) versus 3.1 +/- 11/2.8 +/- 8 mm Hg (placebo) (not significant). Although there was a higher incidence of hypotension on day 1 in the captopril group, the overall incidence of hypotension during the study period was similar in both active treatment groups.

CONCLUSION

Because of differences in initial blood pressure response profiles, short-term treatment with trandolapril tended to be better tolerated than captopril in post-AMI patients with LV dysfunction.

Comparison of perindopril versus captopril for treatment of acute myocardial infarction

Angiotensin-converting enzyme (ACE) inhibitors reduce mortality in patients with acute myocardial infarction (AMI), but these benefits might be limited by acute hemodynamic changes and difficulties in titrating to recommended doses. The objective of this study was to compare the hemodynamic changes and tolerability of perindopril with captopril after AMI. We randomized 212 patients to receive either captopril (n = 102) or perindopril (n = 110) within 72 hours of AMI. Captopril was given as an initial dose of 6.25 mg, and then 50 mg/day on day 1 and 100 mg/day thereafter. The corresponding doses of perindopril were 2, 4, and 8 mg/day. Acute hemodynamic changes, the percentage of patients who reached target doses, and in-hospital and 6-month cardiovascular events were monitored. Baseline clinical characteristics of the 2 groups were identical, but patients randomized to perindopril were in a higher Killip class (1.4 +/- 0.6 vs 1.2 +/- 0.5, p = 0.05). During the first 6 hours, treatment with perindopril resulted in higher minimal systolic (97 +/- 15 vs 91 +/- 14 mm Hg, p <0.01) and diastolic blood pressure (BP) (57 +/- 11 vs 54 +/- 10 mm Hg, p <0.02), later occurrence of minimal BP (3.6 +/- 0.2 vs 2.7 +/- 0.1 hour, p <0.001), and a lower incidence of persistent hypotension with systolic BP < 90 mm Hg for > or =1 hour (5% vs 16%; p < 0.01) compared with captopril. At initial administration, target doses of perindopril and captopril were attained in 97% and 82% of the patients, respectively (p < 0.01). After 6 months, there were no differences between patients treated with perindopril and captopril in mortality rates (6% vs 13%, p = 0.16) and need for revascularization (20% vs 21%, p = 0.9). Thus, in patients during AMI, perindopril treatment showed better short-term tolerance than treatment with captopril, with significantly less acute hemodynamic changes and fewer withdrawals.

Comparison of the first dose response of fosinopril and captopril in congestive heart failure: a randomized, double-blind, placebo controlled study

The purpose of this study was to compare the safety and tolerability of recommended initial doses of fosinopril (FOS) with those of captopril (CAP), in diuretic-treated, salt depleted "high risk" patients with congestive heart failure. Thirty patients were randomized in a double blind fashion to receive a single dose of either FOS 10 mg, CAP 6.25 mg or placebo. CAP produced a significant early and brief fall in BP, while the first-dose hypotensive response with FOS did not differ significantly from placebo. Baseline plasma angiotensin converting enzyme (ACE) activity was similar in all groups. Only CAP showed an acute and significant fall in plasma ACE activity, whereas FOS and placebo did not change ACE activity. There was no correlation between mean arterial pressure or percentile change in mean arterial pressure and plasma ACE activity. Also no correlation was found between high or low ACE activity level and first dose hypotension. The practical importance of the results are: For patients with congestive heart failure. FOS and CAP have different effects on BP after the first dose, and this effect may be dependent on the plasma ACE activity level. FOS produces ACE inhibition and BP changes similar to placebo so it is the safer choice for the treatment of congestive heart failure.

First-dose hypotension after angiotensin-converting enzyme (ACE) inhibitors in chronic heart failure: a comparison of enalapril and perindopril. Slovak Investigator Group

BACKGROUND

First-dose hypotension refers to an observed reduction in blood pressure after the administration of the first dose of ACE inhibitors in patients with congestive heart failure.

AIM

To compare the first-dose responses of low-dose enalapril and perindopril in patients with stable symptomatic chronic heart failure.

METHODS

Single blind, randomised, multicenter, parallel, prospective study. Patients (N=298) with chronic heart failure due to ischemic heart disease or dilated cardiomyopathy, NYHA II-IV, ejection fraction<40%, age>18 years, naive to ACE inhibitors or ATI-receptor blocker, were randomised to receive a single dose of 2. 5 mg enalapril or 2.0 mg perindopril. Baseline laboratory and clinical examinations were performed before entry into the study. Ambulatory blood pressure monitoring started 2 h before the study medication was given, and continued for at least 10 h after the medication.

RESULTS

The maximum drop in blood pressure appeared approximately 4 h after dose administration in both groups, and was more pronounced in the enalapril group. Patients in the enalapril group had a significantly higher incidence of asymptomatic hypotension. No symptomatic hypotension requiring a change in medication or a prolongation of hospitalisation was observed.

CONCLUSION

A low dose of perindopril is well-tolerated at initiation of ACE inhibitor therapy in patients with chronic heart failure and causes less first-dose hypotension than a low dose of enalapril.

Drug-induced orthostatic hypotension in the elderly: avoiding its onset

The prevalence of orthostatic hypotension in the elderly is reported to be 5 to 33%. This high prevalence contributes to the risk of syncope and falls in old age. Drugs are a major cause of postural hypotension. Changes in pharmacokinetics and pharmacodynamics occur with aging in relation to many drugs, resulting in delayed elimination and increased bioavailability. Therefore, drugs with an antihypertensive action (diuretics, calcium antagonists, beta-blockers, ACE inhibitors, alpha 1-blockers, and centrally acting antihypertensives) have a more pronounced effect in the elderly. Nitrates, antiparkinsonian drugs, antidepressants and antipsychotics all cause hypotension as a known adverse effect. When assessing orthostatic hypotension in the elderly, drug treatment should always be reviewed. Whenever possible, antihypertensive drugs should be discontinued, and the dosages of essential drugs should be reduced.

Optimal dosage of ACE inhibitors in older patients

Despite having lower levels of plasma renin activity than younger individuals, elderly patients with hypertension respond well to ACE inhibitors and the drugs have few adverse effects. Plasma concentrations of the active ACE inhibitor are generally higher in the elderly because of decreased renal clearance. These altered pharmacokinetics, combined with impairment of cardiovascular reflexes and the increasing prevalence of heart failure and renal impairment with age, render elderly patients more susceptible to first-dose hypotension. Although many studies have shown that standard dosages are well tolerated it is safer to use lower initial dosages of ACE inhibitors in elderly hypertensive patients because hypotensive reactions are not always predictable. The maintenance dosage may be determined more by the presence of renal disease or heart failure than by age per se. In elderly patients with heart failure, ACE inhibitors should be introduced even more cautiously, using low dosages and preferably under supervision. It may also be necessary to interrupt diuretic treatment for a few days to prevent severe hypotension. The ACE inhibitor dosage should then be titrated up to the maximum that is well tolerated, as this appears to offer the greatest benefit.

Responses to low dose intravenous perindoprilat infusion in salt deplete/salt replete normotensive volunteers

1. Intravenous ACE inhibitor therapy appears to have a role in the treatment of acute heart failure and early after myocardial infarction. Practical experience with intravenous administration with activation of renin is limited. We report responses to perindoprilat (Pt, 0.67 mg) or placebo (P) infused over 4 h in normotensive male volunteers (n = 12, 19-28 years, 53-77 kg) with double-blind, placebo controlled salt depletion (SD) or salt repletion (SR) as a model of the activated renin system. 2. Salt depletion caused no significant fall in serum sodium (P, 139.4 +/- 2.4; Pt, 138.3 +/- 1.9) compared with salt replete preparation (P, 139.9 +/- 1.2; Pt, 139.7 +/- 0.9) but elevation of plasma renin activity 2-3-fold. Pretreatment baseline systolic blood pressure following salt depletion (P, 121 +/- 9.3/71 +/- 7.9; Pt, 121.5 +/- 9.6/69 +/- 8.1) was higher than following salt replete preparation (P, 114 +/- 9.5/61 +/- 7.2; Pt, 116.9 +/- 6.9/67 +/- 7.2). 3. Baseline corrected supine SBP fell significantly and to a similar extent following active treatment regardless of activation of the renin system (SD, -14.6 +/- 9.5/-9.4 +/- 6.4; SR, -12 +/- 14/-10.1 +/- 6.6) compared with placebo (SD, -6.1 +/- 6/-3.7 +/- 5.6; SR, -4.7 +/- 10/-1.3 +/- 6.5). Heart rate was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

First-dose effects of enalapril 2.5 mg and captopril 6.25 mg in patients with heart failure: a double-blind, randomized, multicenter study. The Enalapril-Captopril Investigators

Significant decreases in blood pressure (BP) may occur when administration of angiotensin-converting enzyme (ACE) inhibitors is initiated for the treatment of heart failure. The purpose of this study was to compare the safety and tolerability of recommended initial doses of the longer-acting ACE inhibitor enalapril (ENAL) with those of the shorter-acting captopril (CAP) in patients with heart failure who were treated concomitantly with digitalis and diuretic agents. We evaluated BP, serum ACE activity, and clinical status when a low, first dose of ENAL (2.5 mg, n = 59) or CAP (6.25 mg, n = 58) was administered in a double-blind, randomized, and parallel fashion to 117 patients with mild to moderate heart failure. BP and serum ACE activity were measured at 30 min and hourly for 8 hours after drug administration. BP decreases were similar for both groups (mean supine BP -6.2/-4.8 mm Hg for ENAL vs -8.3/-6.4 mm Hg for CAP; mean standing BP -9.2/-5.6 mm Hg for ENAL vs -10.0/-4.7 mm Hg for CAP). Although the maximum mean decrease in BP occurred at hours 4 and 5 in the ENAL group and hours 1 and 2 in the CAP group, considerable between-group overlap was observed for individual patients. Decreases in mean serum ACE activity occurred earlier and were of shorter duration in the CAP group. ENAL significantly inhibited serum ACE activity to a greater extent than did CAP at all time points except the 1st hour. Administration of a first dose of ENAL, 2.5 mg or CAP, 6.25 mg to patients with heart failure was well tolerated.