U S Pharmacopoeial Convention (USP) has revised its current standards for Heparin sodium injections and Heparin lock flush solutions. The revised standards will become official on May 1, 2013.

Heparin is a widely used anti-coagulant agent, or blood thinner.  Medication errors related to misunderstanding of the expression of total strength on multi-dose product labels have the potential to result in serious consequences to patients.

USP is a scientific not-for-profit organization that develops standards for the identity, strength, quality and purity of drugs and drug ingredients marketed in the US, published in USP’s official compendia, United States Pharmacopoeia and the National Formulary (USP–NF).

The labelling sections of the currently official Heparin sodium injection and Heparin lock flush solution monographs in USP–NF are being revised to ensure that labels comply with General Chapter 1:  Injections. It requires that the label reflect strength per total volume as the primary expression of strength followed in close proximity by strength per milliliter (mL).  It would be 30,000 USP Units/30 mL (1000 USP Units/mL).  Many heparin infusions already display both strength per total volume and strength per mL. This labelling change will mainly impact heparin multiple-dose vials.

In a July 2010 letter from the US Food and Drug Administration (FDA) to USP, referred to data indicating that containers labelled only with product strength statements written as ‘mg per mL’ are often misunderstood by healthcare practitioners as total drug content statements. Such errors could result in improper dosing with serious outcomes, including death. FDA’s concerns were evaluated by USP’s Safe Medication Use Expert Committee, composed of 18 experts.

“We are  committed to developing standards that help to advance public health. Particularly in light of the public health emergency involving adulterated heparin in 2008, USP and FDA are continuing to work closely together to help ensure that heparin delivery is as safe and accurate as possible,” said Dr  Roger L Williams, chief executive officer USP.

Healthcare professionals must be vigilant during the transition period when old labels and revised labels for heparin sodium injections and heparin lock flush solutions both may appear in the marketplace. Old heparin labels may display only “strength per mL,” whereas the revised heparin labels will display both total drug content as “strength per total volume (total mL)” followed in close proximity by “strength per mL.”