>> Barnett: FDA IS NOTIFYING HEALTH CARE PROFESSIONALS AND
PATIENTS ABOUT A NEW USP MONOGRAPH FOR HEPARIN.
UNDER THE NEW MONOGRAPH, THE REFERENCE STANDARD THAT'S
USED TO DETERMINE THE POTENCY OF THE DRUG WILL BE CHANGED IN
ORDER TO MAKE IT COMPATIBLE WITH THE W.H.O.
INTERNATIONAL STANDARD.
DESPITE THESE CHANGES IN THE REFERENCE STANDARD,
HEPARIN DOSAGES WILL CONTINUE TO BE EXPRESSED IN USP UNITS.
PARTLY IN RESPONSE TO THE RECENT HEPARIN CONTAMINATION PROBLEM,
THE NEW MONOGRAPH ALSO INCLUDES ADDITIONAL TEST METHODS THAT CAN
DETECT POTENTIAL IMPURITIES AND CONTAMINANTS.
>> AS A RESULT OF THE CHANGE IN THE REFERENCE STANDARD,
THE POTENCY OF HEPARIN MARKETED IN THE U.S. WILL NOW BE REDUCED
BY ABOUT 10%.
IN OTHER WORDS, THERE COULD BE UP TO A 10%
DECREASE IN HEPARIN ACTIVITY FOR EACH USP UNIT ADMINISTERED.
THIS MEANS THAT SOME PATIENTS MAY REQUIRE MORE HEPARIN TO
ACHIEVE AND MAINTAIN THE DESIRED LEVEL OF ANTICOAGULATION.
PATIENTS MAY ALSO REQUIRE MORE FREQUENT OR INTENSIVE MONITORING
OF aPTT OR ACT.
>> THIS COULD BE ESPECIALLY SIGNIFICANT IN SOME SITUATIONS.
FOR EXAMPLE, WHEN HEPARIN IS ADMINISTERED AS A BOLUS I.V.
DOSE AND IT'S IMPORTANT TO ACHIEVE AN IMMEDIATE
ANTICOAGULANT EFFECT.
THE CHANGES IN HEPARIN POTENCY MAY NOT BE CLINICALLY
SIGNIFICANT WHEN IT'S GIVEN SUBCUTANEOUSLY BECAUSE THE
DRUG'S BIOAVAILABILITY IS LOWER AND MORE VARIABLE WHEN IT'S
ADMINISTERED IN THIS WAY.
>> MANUFACTURERS BEGAN SHIPPING THE NEW HEPARIN PRODUCT IN
EARLY OCTOBER.
FOR A WHILE, BOTH PRODUCTS WILL BE AVAILABLE AT THE SAME TIME,
TO ASSURE THAT THERE'S AN ADEQUATE SUPPLY FOR
ALL PATIENTS.
FDA HAS ASKED THE MANUFACTURERS TO LABEL THEIR HEPARIN TO
DIFFERENTIATE BETWEEN THE OLD AND NEW FORMULATIONS.
>> FDA IS WORKING WITH HEPARIN MANUFACTURERS TO STUDY THE
POSSIBLE IMPACT OF REDUCED HEPARIN POTENCY ON CLINICAL
CARE, AND WE'LL SHARE THE RESULTS OF THESE STUDIES WHEN
THEY'RE AVAILABLE.
