EFFICACY AND DURATION OF ACTION OF SUSTAINED-RELEASE DILTIAZEM IN PATIENTS WITH CHRONIC STABLE EFFORT ANGINA

This double-blind, randomized, placebo-controlled, crossover study was designed to evaluate the effect and duration of sustained-release dil tiazem (DTZ-SR) BID in 16 men with stable effort angina. Exercise test s were performed 8 and 12 hours after the administration of DTZ-SR or placebo. Blood samples for diltiazem plasma concentration levels were taken immediately prior to the exercise test at 12 hours. Statistical analysis was performed using an analysis of variance model for a cross over design. Compared with placebo, DTZ-SR significantly prolonged tot al work from 1982 +/- 992 Kjoules/min to 2327 +/- 876 Kjoules/min (+ 1 7.4%; P < 0.01) at 8 hours and from 1744 +/- 691 Kjoules/min to 2414 /- 987 Kjoules/min (+ 38.4%; P < 0.01) at 12 hours after administratio n. Work load at ischemic threshold was also significantly prolonged fr om 1010 +/- 384 Kjoules/min to 1249 +/- 553 Kjoules/min (+ 23.6%; P < 0.01) at 8 hours and from 963 +/- 425 Kjoules/min to 1210 +/- 639 Kjou les/min (+ 26%; P < 0.01) at 12 hours. In conclusion, our data show th at this sustained-release diltiazem BID formulation improves the exerc ise tolerance of patients with chronic angina and this therapeutic eff ect persists for up to 12 hours after administration.