Source: Lancet  |  Posted 8 years ago

Nifedipine formulations, administered once daily, are more effective than are amlodipine for the management of hypertensive patients, according to researchers.

Acknowledging that calcium channel antagonists can result in a poor prognosis through sympathetic hyperactivity, the researchers - from Shiga University of Medical Science, Otsu, Japan - undertook a comparative study of the two drugs in 36 patients with essential hypertension.

Patients who had been receiving sustained-release nifedipine were given amlodipine instead and those who had previously been treated with amlodipine now received coat-core nifedipine.

The researchers noted that hypertensive symptoms had no significant effect among patients receiving either amlodipine nor coat-core nifedipine. But, the plasma levels of norepinephrine, renin, and aldosterone were noticeably lower in patients whose sustained -release nifedipine was substituted for amlodipine.

There was also no significant change in the plasma levels of norepinephrine, renin and aldosterone following substitution of amlodipine by coat-core nifedipine.

The researchers concluded that coat-core nifedipine may not increase the sympathetic nerve activity seen in amlodipine at the effective anti-hypertensive concentrations of the two drugs. In addition, the nifedipine formulations duration of action is an important determinant for nifedipine- induced hyperactivity in the reflex sympathetic nerve and the renin-angiotensin systems.