Prolonged antihypertensive effect of amlodipine: a prospective double-blind randomized study

The effects of missed doses of amlodipine and losartan on blood pressure in older hypertensive patients

This randomized, double-blind, parallel-group, multicenter study compared the efficacy of amlodipine and losartan in an older hypertensive population, focusing on therapeutic coverage in the case of missed doses. Following a 4-week, single-blind, placebo washout period, 211 patients were randomly assigned to receive either 5 mg of amlodipine once daily or 50 mg of losartan once daily. Doses were doubled after 6 weeks of treatment if the diastolic blood pressure exceeded 90 mm Hg. After the 12-week treatment period, patients received the placebo for 2 days (drug holiday) to simulate two missed doses of antihypertensive medication. Twenty-four-hour ambulatory blood pressure monitoring was conducted at the end of the placebo washout period (baseline), upon completion of the 12-week treatment period (steady state), and after the 2-day drug holiday. Amlodipine was more effective than losartan in reducing patients' 24-h ambulatory blood pressure at the steady-state sampling time. The increases in 24-h blood pressure during the drug holiday averaged 6±2/2±1 mm Hg (P<0.0001) in the amlodipine group and 3±2/2±1 mm Hg (P<0.0001) in the losartan group. The rise in systolic pressure was greater in patients on amlodipine than in those on losartan (P<0.0001). For diastolic pressure, the changes did not differ. Owing to the lower pressure during treatment, patients in the amlodipine group remained at a significantly lower blood pressure level after the 2-day drug holiday. Amlodipine was more effective than losartan in lowering blood pressure and in maintaining blood pressure control after two missed doses, and the difference was most significant for systolic blood pressure.

Antihypertensive Efficacy of Amlodipine and Losartan after Two ‘Missed’ Doses in Patients with Mild to Moderate Essential Hypertension

We compared the effects of amlodipine (5 − 10 mg, n = 94) and losartan (50 − 100 mg, n = 94) on the lowering of blood pressure (BP) at steady state and after two missed doses, as well as on tolerability. This was a randomized, double-blind study of 12 weeks of active treatment followed by 2 days of placebo treatment. Twenty-four-hour ambulatory blood pressure monitoring and office BP measurements were performed at baseline, week 12 and after the 2-day drug holiday. After 12 weeks, amlodipine was significantly more effective than losartan in reducing both 24-h systolic blood pressure (SBP) (−18.0 versus −10.8 mmHg) and diastolic blood pressure (DBP) (−10.6 versus −8.0 mmHg). While mean SBP and DBP for both treatments increased comparably during the drug holiday, BP values remained significantly lower than baseline for both treatments. The superior BP-lowering effect of amlodipine compared with losartan was maintained during the drug holiday.

Patterns of nonadherence to antihypertensive therapy in primary care

Nonadherence to medications is an important cause of poor blood pressure control. Long-acting antihypertensive agents could theoretically be beneficial in partially adherent patients, who are commonly seen in contemporary practice. Little has been reported about the duration of drug holidays (DHs) in treated hypertensives outside of generally compliant patients in phase 4 clinical trials. The authors described patterns of nonadherence to single and multiple antihypertensives in a random sample of 120 primary care patients with uncontrolled hypertension. Adherence to up to 3 antihypertensives was measured by electronic monitoring. Frequencies of single-day omissions and DHs of 2 consecutive days (DH2), 3 days (DH3), or ≥4 days (DH≥4) for each drug were calculated. Overall, 89 (74%) of patients had at least a 1-day omission. A single day omission was found in 61.4% of the patients taking 1 drug, followed by DH≥4 (28.1%), DH2 (26.3%), and DH3 (8.8%). In patients using multiple drugs, single-day omissions were also most common, followed by DH≥4, DH2, and DH3. Omissions of ≤3 days comprise on average 74% of all omissions. Although encouraging full adherence remains important, it may be prudent to prescribe long-acting antihypertensive agents, which can compensate for the majority of dose omissions.

Monitoring of adverse drug reactions associated with antihypertensive medicines at a university teaching hospital in New Delhi

Aim

To monitor the adverse drug reactions (ADRs) caused by antihypertensive medicines prescribed in a university teaching hospital.

Methods

The present work was an open, non-comparative, observational study conducted on hypertensive patients attending the Medicine OPD of Majeedia Hospital, Jamia Hamdard, New Delhi, India by conducting patient interviews and recording the data on ADR monitoring form as recommended by Central Drugs Standard Control Organization (CDSCO), Government of India.

Results

A total of 21 adverse drug reactions were observed in 192 hypertensive patients. Incidence of adverse drug reactions was found to be higher in patients more than 40 years in age, and females experienced more ADRs (n = 14, 7.29%) than males, 7 (3.64%). Combination therapy was associated with more number of adverse drug reactions (66.7%) as against monotherapy (33.3%). Calcium channel blockers were found to be the most frequently associated drugs with adverse drug reactions (n = 7), followed by diuretics (n = 5), and β-blockers (n = 4). Among individual drugs, amlodipine was found to be the commonest drug associated with adverse drug reactions (n = 7), followed by torasemide (n = 3). Adverse drug reactions associated with central nervous system were found to be the most frequent (42.8%) followed by musculo-skeletal complaints (23.8%) and gastro-intestinal disorders (14.3%).

Conclusions

The present pharmacovigilance study represents the adverse drug reaction profile of the antihypertensive medicines prescribed in our university teaching hospital. The above findings would be useful for physicians in rational prescribing. Calcium channel blockers were found to be the most frequently associated drugs with adverse drug reactions.

ACE inhibitor-based, directly observed therapy for hypertension in hemodialysis patients

BACKGROUND

Hypertension is present in nearly 80% of dialysis patients yet adequately controlled in less than half. We designed a stepped antihypertensive regimen using long-acting antihypertensives (trandolapril, atenolol and amlodipine) administered thrice a week (TIW) after each hemodialysis, and compared blood pressure (BP) control, medication cost and pill burden to each patient's prior daily antihypertensive prescriptions.

METHODS

Patients were continued on their daily medications, pre-dialysis sitting BP was measured and a 44-hour interdialytic ambulatory BP monitoring (ABPM) was obtained. Then, their medications were stopped and replaced with trandolapril (2 mg TIW). Atenolol and/or amlodipine were also given TIW if the patients had any member of these classes of drugs as part of their daily regimen. Medications were titrated every 2 weeks to achieve a pre-dialysis mean arterial pressure (MAP) of <107 mm Hg. After 2 consecutive weeks with a pre-dialysis MAP of <107 mm Hg, a second 44-hour ABPM was obtained.

RESULTS

Ten patients completed the study. A persistent MAP of <107 was maintained in all 10 patients after conversion to TIW dosing. The systolic BP decreased from 122.2 +/- 7.1 to 116.4 +/- 11.6, and the diastolic BP decreased from 75.3 +/- 10.4 to 70.4 +/- 11.4 mm Hg. Pill burden and cost of medications were also significantly less.

CONCLUSIONS

This pilot study found that ACE inhibitor-based, directly observed TIW therapy to be effective in hemodialysis patients with mild to moderate hypertension. Larger trials of directly observed therapy for hypertension in dialysis patients are warranted.

Amlodipine decreases fibrosis and cardiac hypertrophy in spontaneously hypertensive rats: persistent effects after withdrawal

Our objective was to examine the effect of chronic treatment with amlodipine on blood pressure, left ventricular hypertrophy, and fibrosis in spontaneously hypertensive rats and the persistence of such an effect after drug withdrawal. We investigated the effects of treatment with 2, 8 and 20 mg/kg/day of amlodipine given orally for six months and at three months after drug withdrawal. Systolic blood pressure was measured using the tail-cuff method. At the end of the study period, the heart was excised, the left ventricle was isolated, and the left ventricle weight/body weight ratio was calculated as a left ventricular hypertrophy index. Fibrosis, expressed as collagen volume fraction, was evaluated using an automated image-analysis system on sections stained with Sirius red. Age-matched untreated Wistar-Kyoto and SHR were used as normotensive and hypertensive controls, respectively. Systolic blood pressure was reduced in the treated SHR in a dose-dependent way and after amlodipine withdrawal it increased progressively, without reaching the values of the hypertensive controls. Cardiac hypertrophy was reduced by 8 and 20 mg/kg/day amlodipine, but when treatment was withdrawn only the group treated with 8 mg/kg/day maintained significant differences versus the hypertensive controls. All three doses of amlodipine reduced cardiac fibrosis and this regression persisted with the two highest doses after three months without treatment. We concluded that antihypertensive treatment with amlodipine is accompanied by a reduction in left ventricular hypertrophy and regression in collagen deposition. Treatment was more effective in preventing fibrosis than in preventing ventricular hypertrophy after drug withdrawal.

Comparison of the effects of a 7-day period of non-compliance on blood pressure control using three different antihypertensive agents

OBJECTIVES

To compare blood pressure control during 7 days of drug omission in patients taking bendroflumethiazide 2.5 mg, nifedipine LA 30 mg or enalapril 20 mg once daily and, secondarily, to measure patient compliance.

METHODS

Twenty-four patients with hypertension were assigned, in a random crossover fashion, to a sequence of bendroflumethiazide, nifedipine LA and enalapril, each for 4 weeks, followed by a 1-week period of dose omission. The patients measured their own blood pressure daily using an Omron 705CP monitor. Differences in blood pressure from baseline (mean blood pressure during week 4 on treatment) and the week of dose omission were compared between the three drugs. Patient compliance was measured using pill counts and the Medication Event Monitoring System.

RESULTS

Bendroflumethiazide maintained blood pressure control during drug omission for longer than enalapril or nifedipine LA. The magnitudes of the increase in systolic blood pressure (SBP) between baseline and day 7 off treatment were 7.0, 12.2 and 9.7 mmHg for bendroflumethiazide, nifedipine LA and enalapril, respectively. For diastolic blood pressure (DBP), the values were 2.9, 5.3 and 7.3 mmHg for bendroflumethiazide, nifedipine LA and enalapril, respectively. Differences in SBP between bendroflumethiazide and the comparator drugs occurred at day 2 off treatment. Differences in DBP between bendroflumethiazide and nifedipine were apparent on days 2 and 3 off treatment. Differences in DBP between bendroflumethiazide and enalapril were apparent on days 2, 3, 4 and 5 off treatment. Patient compliance throughout the study was high in terms of both taking the medication when required and omitting the medication when required.

CONCLUSIONS

Bendroflumethiazide maintained blood pressure control during a period of drug omission better than nifedipine or enalapril.

Azelnidipine and amlodipine: a comparison of their pharmacokinetics and effects on ambulatory blood pressure

We objected: 1) To compare the effects of azelnidipine and amlodipine on 24-h blood pressure; 2) To monitor the plasma concentration vs. the time profile in order to assess the association between pharmacokinetics and hypotensive activity after administration of either drug for 6 weeks. Blood pressure and pulse rate were measured by 24-h monitoring with a portable automatic monitor in a randomized double-blind study of 46 patients with essential hypertension. Azelnidipine 16 mg (23 patients) or amlodipine 5 mg (23 patients) was administered once daily for 6 weeks. Pharmacokinetics were analyzed after the last dose was taken. Both drugs showed similar effects on the office blood pressure and pulse rate. During 24-h monitoring, both drugs caused a decrease in systolic blood pressure of 13 mmHg and had a similar hypotensive profile during the daytime period (07:00-21:30). The pulse rate decreased by 2 beats/min in the azelnidipine group, whereas it significantly increased by 4 beats/min in the amlodipine group. Similar trends in the blood pressure and pulse rate were observed during the nighttime (22:00-6:30) and over 24 h. Excessive blood pressure reduction during the nighttime was not seen in either group. The pharmacokinetic results indicated that the plasma half-life (t1/2) of amlodipine was 38.5 +/- 19.8 h and that of azelnidipine was 8.68 +/- 1.33 h. Despite this difference in pharmacokinetics, the hypotensive effects of amlodipine and azelnidipine were similar throughout the 24-h administration period.