Inotropic agents are a class of agents which affects the force of muscle contractions, particularly cardiac contractions. Negative intropic agents decrease the force of contractions while positive inotropic agents increase them.
 
 
Recommended Resources
Classification of Positive Inotropic Agents
Article on the Ion Channel site defines this classification of positive inotropic agents as well as numerous related articles.
http://www.ionchannels.org/showabstract.php?pmid=7691913&redirect=yes&terms=inotropic+agents
Inotropic Agents in Heart ailure Due to Systolic Dysfunction
Features a paper wherein the author discusses heart failure therapy with systolic dysfunction which is addressed with inotropic agents and points out that these therapies are contraindicated for patients using ACE inhibitors, beta blockers, or loop diuretics.
http://www.uptodate.com/patients/content/topic.do?topicKey=~htBWvIM/89qkKh
Offers details about the inotropic agent Lanoxin, which is known by the generic name of digoxin. Contains a basic overview, side effects and interactions, and special precautions.
http://www.healthcentral.com/peoplespharmacy/408/drugs/brand/96_overview/Lanoxin.html