title: Classification of positive inotropic agents.
abstract: Although there is increasing recognition that all inotropic agents are not alike, they continue to be viewed in the generic sense because of the lack of a classification system. Analogous to the classification system proposed for the antiarrhythmic agents over 20 years ago, a classification system is proposed that categorizes inotropic agents according to their mechanisms of action. Agents are classified as those that augment contractility by increasing intracellular levels of cyclic adenosine monophosphate (class I); affect ion channels or pumps (class II); modulate intracellular calcium regulation (class III), and augment contractility through multiple pathways (class IV). This classification system does not suggest that some classes of inotropic agents might be more effective than others nor does it imply that potential beneficial effects are shared by all members of each class of drugs. However, it provides a framework for better understanding of the potential benefits and limitations of the traditional inotropic agents as well as the increasing number of new investigational drugs.
authors.affiliation: Peter Belfer Cardiac Laboratories, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: A M
authors.initials: AM
authors.lastname: Feldman
mesh_terms: D002118:Calcium / Q000032:analysis; D002316:Cardiotonic Agents / Q000145:classification* / Q000494:pharmacology* / Q000627:therapeutic use; D000242:Cyclic AMP / Q000032:analysis; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007424:Intracellular Fluid / Q000737:chemistry / Q000187:drug effects; D007473:Ion Channels / Q000187:drug effects; D009124:Muscle Proteins / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects*; D012508:Sarcolemma / Q000187:drug effects
chemical_list: D002316:Cardiotonic Agents; D007473:Ion Channels; D009124:Muscle Proteins; D000242:Cyclic AMP; D002118:Calcium