Nifedipine and diltiazem should be considered as first-line drugs for treating patients with hypertension, according to findings from two studies presented at the 10th European Society of Hypertension meeting in Gothenburg, Sweden.
Results from a new trial suggest that nifedipine GITS (Adalat LA) may be useful as an alternative first line treatment of hypertensive patients with additional cardiovascular risk factors, such as diabetes or smoking.
The results of the trial, which were announced on June 2, showed that nifedipine GITS and a hydrochlorothiazide/amiloride combination were equally effective at reducing cardiovascular and cerebrovascular morbidity and mortality.
"Lowering blood pressure in patients with hypertension is important and having another product available to do this is an advantage, especially as nifedipine appeared to be as safe as diuretics, even in diabetics. Using a calcium channel blocker might even be a better option than using high-dose diuretics but we should be cautious about extrapolating these results to all calcium channel blockers," Professor Morris Brown (clinical pharmacology unit, Addenbrooke's hospital, Cambridge), one of the trial investigators, told The Journal on June 2.
Over 6,000 patients were randomised to the international nifedipine GITS study: intervention as a goal in hypertension treatment (INSIGHT) and, after a one-month "wash out" period, were randomised to receive either 30mg nifedipine GITS or a combination of 25mg hydrochlorothiazide and 5mg amiloride.
All patients entered the trial with a blood pressure of at least 150/95mmHg or a systolic blood pressure of greater than 160mmHg and had at least one additional cardiac risk factor. They were followed up for an average of 3.5 years.
Blood pressure was reduced from an average of 173/99mmHg to 138/82mmHg for both groups. In two-thirds of patients in both groups, this was achieved with monotherapy, while the rest required additional treatment with either atenolol or enalapril. Blood pressure reduction in subjects with diabetes was similar to that achieved in those without the disease, the investigators say.
Morbidity and mortality from cerebro- and cardiovascular events was comparable in both groups, as was total mortality. More patients suffered from ankle oedema and headache in the nifedipine group but there were fewer cases of electrolyte imbalance and metabolic disturbances than in those taking diuretics.
Diltiazem is as effective as diuretics and beta-blockers in preventing cardiovascular and cerebrovascular events in patients with mild to moderate hypertension, say the Nordic diltiazem study (NORDIL) investigators.
Patients in the diltiazem group were less likely to suffer fatal or non-fatal stroke than those in the group receiving beta-blockers and/or thiazide diuretics.
Diastolic blood pressure was reduced to a similar degree in both treatment groups but the decrease in systolic blood pressure in patients taking diltiazem was less than in the beta-blocker/diuretic group.
"Diltiazem has demonstrated cardiovascular morbidity and mortality benefits which are similar to those of conventional therapy," said Professor Lennart Hansson (department of health and social sciences, University of Uppsala, Sweden).
The NORDIL investigators presented their findings on May 30, saying that 10,881 patients with a diastolic blood pressure of at least 100mmHg had been involved in the trial. They were randomised to receive either diltiazem or a beta-blocker and/or a diuretic.
The average reduction in blood pressure was 20.3/18.7mmHg in the diltiazem group compared with 23.3/18.7mmHg in the other group.
Overall, there was no difference in mortality between the two treatment groups.
There was a significant difference between the groups in terms of fatal and non-fatal stroke, with a rate of 6.4 per 1,000 patient years (P=0.04) in the diltiazem group and 7.9 per 1,000 patient years (P=0.17) in the other group. Conversely, fatal and non-fatal myocardial infarction was more common in the diltiazem group than in the other group (7.4 and 6.3 events per 1,000 patient years, respectively).
The INSIGHT trial was supported by Bayer and the NORDIL trial by both Pharmacia & Upjohn and Sanofi-Synthélabo.
Current British Hypertension Society guidelines recommend thiazides or beta-blockers as first-line treatment of hypertension unless there is a contraindication or a compelling indication for another drug.