OBJECTIVE: To compare clinically relevant pharmacokinetic, pharmacodynamic and 
toxico logical characteristics of calcium-modulating compounds used in ischemic 
heart disease.
DATA SOURCES: A MEDLINE search (1990 pt B to 1991 pt A revised for 1993; 1991 pt 
B to 1992 revised for 1993; and January to May 1993) combining the search 
phrases 'calcium channel blockers', 'myocardial ischemia', 'pharmacodynamics' 
and 'pharmacokinetics', and a search in Compact Cambridge Drug Information 
Source vol-6 (revised 1992, fourth quarter) using the search phrase 'calcium 
antagonists' and medical subject headings (MeSH) 'pharmacokinetics' and 
'pharmacodynamics' were used to obtain title and abstract information on 
available current literature.
STUDY SELECTION: Review articles, proceedings and studies published in English 
and available within the University of Saskatchewan library system, as they 
appeared to relate closely to the objective, were obtained for closer 
evaluation. In addition, primary references were examined, and journal reprints 
were selected from the authors' files.
DATA EXTRACTION: The focus was on studies and objective reviews that profiled 
one or more representative compounds in a manner suitable for deriving 
background and comparative information pertaining to the objective. Data from 
multiple studies, or from studies that employed multiple methodological 
approaches, were preferentially extracted and summarized for presentation.
DATA SYNTHESIS: The role of calcium in cardiac and vascular smooth muscle 
physiology was reviewed, highlighting the major mechanisms responsible for 
maintaining calcium homeostasis in these cells. With a focus on verapamil, 
diltiazem and 1,4-dihydropyridines currently employed in the treatment of 
cardiovascular disorders, a general survey of their sites of action, tissue 
selective pharmacodynamics, pharmacokinetic properties and side effects was 
undertaken in a comparative context.
CONCLUSIONS: Calcium antagonists are employed in the treatment of angina, 
certain cardiac arrhythmias and hypertension. They are a chemically and 
pharmacologically heterogeneous group of compounds that act principally to 
inhibit the influx of calcium across certain voltage-dependent membrane 
channels. Concepts pertaining to calcium mobilization in the pathophysiology of 
myocardial ischemia, particularly at the molecular level, have evolved 
remarkably over the past decade. The repertoire of agents having 
calcium-regulating properties has expanded in parallel. The task of integrating 
new knowledge in both of these areas requires further attention in order to 
determine optimal approaches to treatment.