Effect of long-term nifedipine treatment on body fluid composition in essential hypertension.

The antihypertensive efficacy and effects on body fluid composition of monotherapy with the calcium antagonist nifedipine were investigated in 15 patients with essential hypertension. The systolic as well as the diastolic blood pressure decreased significantly, by approximately 12%, during nifedipine treatment with a mean dose of 56 mg. Glomerular filtration rate, plasma volume, extracellular fluid volume, and the ratio plasma to interstitial fluid volume did not change significantly. The most frequently observed side-effects were flushing and peripheral oedema which occurred in four and three patients, respectively. These results indicate that sodium and water retention, which is often observed during long-term treatment with vasodilators, does not seem to be the explanation of the development of peripheral oedema seen with nifedipine.