exchangeable sodium , blood volume , plasma norepinephrine , epinephrine , renin levels , and pressor responses to infused norepinephrine or angiotensin ii were assessed in 10 patients with essential hypertension on placebo , following six to eight weeks of monotherapy with nifedipine , 3 x 10-20 mg/day , and after six to eight weeks on nifedipine combined with the diuretic chlorthalidone , 25 to 50 mg/day .
C0028351
norepinephrine
C0014563
epinephrine