Heparin Overdoses

Last fall, a hospital had an unfortunate medication error event in the Newborn Intensive Care Unit. Six babies were given 10,000 units/ml when they should have been given HEP-LOCK 10 units/ml. For at least three of the babies, the consequences were life- ending.

Heparin is an anti-clotting medication. It not only inhibits reactions that lead to the clotting of blood but also to the formation of fibrin clots. It works at multiple sites within the coagulation system so that when given in wrong amounts, the consequences are often seen throughout multiple areas of the body. While bleeding time is not usually affected, clotting time is prolonged by the medication. This can prevent patients from unnecessary bleeding when on this drug regimen.

The Institute for Safe Medication practices has long included heparin on its list of high alert medications. This particular medication is categorized by the institute as having a higher chance than other medications of doing harm to patients if used incorrectly. The medication error noted in this specific instance occurred because the labels on the vials were inadvertently switched in the pharmacy.

Since this incident, the hospital where it occurred and many others across the country have had policies and procedures changed along with educational in-services for hospital staff. Some hospitals have made the decision to no longer stock the 10,000 units/ml vials. In addition, nurses now double check that they are giving the right concentration of heparin prior to administering the medication.

These practices for some medical professionals are still considered not enough. In order to completely eliminate the chance that a patient, particularly an infant, receives the wrong concentration of heparin some hospitals flush lines with normal sodium chloride. This practice has proven to keep intravenous lines open while decreasing the threat of heparin overdose.

Baxter, the manufacturer of the heparin vials that were mixed up, did send a safety alert letter to healthcare providers to make them aware of the incident and the potential for it to occur again. In their letter they also reminded healthcare professionals to never rely on color as a sole indicator to differentiate between products. Baxter also encouraged hospitals to notify all staff members of the potential for errors in dispensing and administering heparin, and encouraged the use of color photographs of the vials to remind staff of the closeness in vial labeling.

References:
Baxter, Important Medication Safety Alert: Baxter Heparin Sodium Injection 10,000 Units/ml and Hep-Lock U/P Units/ml, February 2006 Retrieved from http://www.fda.gov

Heparin: Clinical Pharmacology. Retrieved July 2007 from http://www.rxlist.com/cgi/generic/heparin_cp.htm

Magill-Lewis, J. Caution: Heparin errors can have fatal results. April 2, 2007 Retrieved July 2007 from http://www.drugtopics.com/drugtopics/content