The safety and antihypertensive efficacy of PN 200-110 (isradipine), a novel 
calcium antagonist, are discussed in a preliminary report of double-blind, 
multicenter, controlled, phase III clinical trials for essential hypertension. 
Patients who qualified for entry after a 3 week placebo-washout period were 
enrolled in 1 of 5 studies; 2 studies were placebo controlled; 3 studies 
evaluated PN 200-110 against 1 of 3 active controls: hydrochlorothiazide (HCTZ) 
propranolol or prazosin. A separate study assessing the effects of PN 200-110 in 
combination with HCTZ versus propranolol plus HCTZ is also discussed. Compared 
with placebo, PN 200-110 decreased mean supine systolic and diastolic blood 
pressures by 20/16 mm Hg versus 4/6 mm Hg. Compared with placebo and active 
control drugs, PN 200-110 normalized supine diastolic blood pressure to less 
than or equal to 90 mm Hg in 72% of patients, versus 13% in the placebo group, 
74% in the HCTZ group, 45% in the propranolol group and 69% in the prazosin 
group. In the ability to decrease diastolic blood pressure by greater than or 
equal to 10 mm Hg, PN 200-110 compared favorably to prazosin (81% vs 81%), and 
was superior to HCTZ (81% vs 61%) and propranolol (81% vs 36%). In combination 
with HCTZ, PN 200-110 exerted as great an antihypertensive effect as propranolol 
plus HCTZ. Long-term therapy with PN 200-110 was also effective. Supine systolic 
and diastolic blood pressures decreased a mean of 15/13 mm Hg at 3 months, and 
18/20 mm Hg at 12 months. PN 200-110 is well tolerated with relatively few 
adverse effects reported.