Unstable angina / non ST elevation myocardial infarction unfractionated heparin therapy


 * Associate Editors-in-Chief: Varun Kumar, M.B.B.S.; Lakshmi Gopalakrishnan, M.B.B.S.; Smita Kohli, M.D.

Unfractionated Heparin(UFH)
Mechanism of action:
 * Unfractionated heparin exerts its anticoagulant effect by potentiating the action of circulating antithrombin, a proteolytic enzyme that inactivates factor IIa (thrombin), factor IXa, and factor Xa.
 * It prevents thrombus propagation but does not lyse existing thrombi.

Clinical trial data:
 * A meta-analysis showed that in aspirin-treated patients with acute coronary syndrome without ST elevation, short-term unfractionated heparin or LMWH halves the risk of myocardial infarction or death.

Dosing:
 * This is a short acting drug with an anticoagulation half life of 1.5hrs. Hence, frequent monitoring of the anticoagulant response using activated partial thromboplastin time (APTT) is recommended with titrations made according to a standardized nomogram aiming for an APTT range between 1.5 to 2 times control or 50 to 70 seconds.

Adverse effects:
 * bleeding(specially with elevated APTT)
 * heparin induced thrombocytopenia