Description

Delayed Onset of HIT and HITT 
Heparin-induced Thrombocytopenia and Heparin-induced Thrombocytopenia and Thrombosis 
can occur up to several weeks after the discontinuation of heparin therapy. Patients presenting 
with thrombocytopenia or thrombosis after discontinuation of heparin should be evaluated for 
HIT and HITT. 
Use in Neonates and Infants 
The 100 unit/mL concentration should not be used in neonates or in infants who weigh less than 10 kg 
because of the risk of systemic anticoagulation. Caution is necessary when using the 10 unit/mL 
concentration in premature infants who weigh less than 1 kg who are receiving frequent flushes since a 
therapeutic heparin dose may be given to the infant in a 24-hour period. 
PRECAUTIONS 
General 
Precautions must be exercised when drugs that are incompatible with heparin are administered through 
an indwelling intravenous catheter containing Preservative-Free Heparin Lock Flush Solution. (See 
DOSAGE AND ADMINISTRATION, Maintenance of Patency of Intravenous Devices.) The 
concentration of phosphorus in the heparin solution is 0.63 mg/mL.

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NDA 17-037/S-158 
Page 27 
Thrombocytopenia, Heparin-induced Thrombocytopenia (HIT) and Heparin-induced 
Thrombocytopenia and Thrombosis (HITT) 
See WARNINGS. 
Increased Risk to Older Patients, Especially Women 
A higher incidence of bleeding has been reported in patients, particularly women, over 60 years of age. 
Laboratory Tests 
Periodic platelet counts, hematocrits and tests for occult blood in stool are recommended during the 
entire course of heparin use (see DOSAGE AND ADMINISTRATION). 
Drug Interactions 
Platelet Inhibitors 
Drugs such as acetylsalicylic acid, dextran, phenylbutazone, ibuprofen, indomethacin, dipyridamole, 
hydroxychloroquine and others that interfere with platelet-aggregation reactions (the main hemostatic 
defense of heparinized patients) may induce bleeding and should be used with caution in patients 
receiving heparin sodium. 
Other Interactions 
Digitalis, tetracyclines, nicotine or antihistamines may partially counteract the anticoagulant action of 
heparin sodium.