The FDA has upheld its previous recommendations that physicians should exude clinical judgment when administering heparin sodium, made under the U.S. Pharmacopeia (USP),  to patients after clinical trials have shown that the drug holds 10 percent less anticoagulant activity compared to heparin previously manufactured.

The agency first made physicians aware of the changes of the potency of the drug in October 2009 and asked physicians to become aware of the need for dosage adjustments and monitoring.

The FDA also is recommending that physicians and hospitals do not use the old and new heparin drug doses interchangeably and separate the “old” and “new” before transitioning to using the USP heparin. According to the FDA, in-vivo and in-vitro clinical studies were performed and showed consistent results in exhibiting the 10 percent decrease in heparin potency.

Additionally, those same studies showed a large variation in activated partial thromboplastin time (aPTT) responses to doses of heparin, and concluded that the reduction in dose may not be exhibited in results of aPTT or activated clotting time results in patients.

The agency offered the following information on how to identify new USP standard heparin products from various manufacturers:

• APP -- the "N" will appear after the expiration date;
• B.Braun -- the "N" will appear after the lot number;
• Hospira -- Lot numbers will begin with the number "82" or higher; and
• Baxter -- "N" will appear before the lot number.

 
While the FDA found that the dilution of heparin did not have significant affects on clinical practice, it said that pediatric patients or those undergoing cardiac surgery should be closely monitored.