Most episodes of ambulatory ischemia are associated with a preceding period of increased heart rate. The likelihood of developing ischemia is predicted by heart rate variables and unaffected by time of day. Anti-ischemic efficacy is generally a result of the medication's efficacy in reducing heart rate variables. A minority of ischemic episodes are not associated with preceding periods of increased heart rate, may be caused by episodic coronary vasoconstriction, and are more effectively reduced by nifedipine than propranolol.
To evaluate whether a significant statistical correlation exists between earlobe crease (EC) and coronary heart disease (CHD), 1000 Japanese adult patients (573 males, 427 females) were examined for the presence or absence of EC, clinical or angiographic evidence of CHD, and the following coronary risk factors: male sex, age over 50 years, obesity, hypertension, diabetes mellitus, cigarette smoking, and hyperlipidemia. Patients were divided into two groups according to clinical evidence of CHD: 237 patients with angina pectoris and/or myocardial infarction (CHD+ group); 720 patients without evidence of CHD (CHD- group). Coronary angiography was performed on 200 patients from this sample population; these patients were also divided into two groups: 119 patients with greater than 50% luminal narrowing of at least one major coronary artery (stenosis+ group); 81 patients with no significant atherosclerotic changes in the coronary arteries (stenosis- group). EC was present in 58 of 237 CHD+ patients (24.5%) but in only 35 of 720 CHD- patients (4.8%; P less than 0.001); it was present in 31 of 199 stenosis+ patients (26.1%) but in only 3 of 81 stenosis- patients (3.7%; P less than 0.01). EC was also found to correlate significantly with some coronary risk factors; the correlations between the presence of EC and the presence of CHD and coronary risk factors were investigated by multivariate analysis. In a multivariate setting, the existence of CHD and an age of over 50 years was significantly related to the presence of EC. To investigate the relationship between EC and advancing age, all patients were separated into age-groups.(ABSTRACT TRUNCATED AT 250 WORDS)
The effect of diltiazem pretreatment on the pharmacokinetics of nifedipine were determined in six healthy male volunteers. Placebo or diltiazem (30 mg and 90 mg) was given orally three times daily for 3 days in a double-blind, Latin square method. On the fourth day, a 20-mg nifedipine was given orally 1 hour after the last dose of placebo or diltiazem. The mean elimination half-life of nifedipine prolonged significantly following diltiazem (2.54 hours on placebo vs 3.40 hours on 30 mg diltiazem and 3.47 on 90 mg diltiazem, both P less than .01). The mean AUC of nifedipine increased during diltiazem (1726.6 nmol X hr/ml on placebo vs 3838.0 on 30 mg diltiazem, and 5370.0 on 90 mg diltiazem, both P less than .05, 30 mg vs 90 mg, 0.1 less than P less than .05). The ratio of the AUC of primary metabolite (nitropyridine form) to the AUC of nifedipine was reduced by diltiazem pretreatment in a dose-dependent manner. ICG clearance was not influenced following diltiazem. These results indicate that diltiazem dose-dependently alters the pharmacokinetic profiles of nifedipine. The ICG clearance test showed that the liver blood flow did not decrease during diltiazem therapy, therefore, the reduction in the metabolic clearance of nifedipine might be caused by inhibiting effect of diltiazem on the activity of drug oxidizing enzymes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.