[A multicenter, randomized clinical trial of intravenous diltiazem in treatment of unstable angina].
OBJECTIVE
To investigate the clinical efficacy and safety of intravenous diltiazem compared with nitroglycerin in the patients with unstable angina pectoris.


METHODS
A multicenter, randomized, open-label, parallel group trial was conducted. A total of 213 eligible patients were enrolled. They were randomized either to diltiazem or nitroglycerin treatment. The diltiazem was administered from 100 microg/min at the initiation of treatment, the largest dosage was 200 - 300 microg/min; the nitroglycerin was administered from 20 microg/min at the initiation of treatment. The largest dosage was 80 - 100 microg/min. Intravenous infusion was kept over 48 hours. The endpoints included refractory angina pectoris, acute myocardial infarction, death, emergency PTCA and CABG.


RESULTS
(1) Intravenous diltiazem was effective on the improvement of symptom and electrocardiogram, and its effects were similar to intravenous nitroglycerin. (2) Compared with nitroglycerin, intravenous diltiazem lowered heart rate and myocardial oxygen consumption index (systolic pressure x heart rate) to more extent significantly. (3) After treatment, the onsets of refractory angina pectoris were reduced more significantly in the diltiazem group than in nitroglycerin group [4 (3.8%) vs 13 (11.9%), RR 0.32 (95% CI 0.11 - 0.96), P < 0.05]. (4) The patients whose heart rate were reduced significantly (<or= 50 beats per minute) in the diltiazem group were more than in the nitroglycerin group [8 (7.7%) vs 0 (0%), P < 0.01]. But these patients could tolerate the lower heart rate very well in the diltiazem group. (5) The needs of beta receptor blocker or calcium antagonists were reduced more significantly in the diltiazem group compared with those in the nitroglycerin group [2 (1.9%) vs 13 (11.9%), P < 0.01].


CONCLUSIONS
Intravenous diltiazem therapy is effective and safe for patients with unstable angina pectoris. It may significantly lower the risk of refractory angina pectoris compared with intravenous nitroglycerin.
D000368:Aged; D000789:Angina, Unstable / Q000188:drug therapy*; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use*; D004110:Diltiazem / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008875:Middle Aged; D016896:Treatment Outcome
D002121:Calcium Channel Blockers; D004110:Diltiazem