Unfractionated heparin: Difference between revisions

Revision as of 19:08, 20 April 2019

General

Type: Anticoagulant
Dosage Forms: IV, SC
Common Trade Names: Heparin

Adult Dosing

See University of Washington pharmacy heparin infusion guidelines

Thromboembolism

Bolus: 80 units/kg IV x 1 (MAX: 5,000 units)
Then drip: 18 units/kg/h IV (MAX: 1,000 units/h)
Adjust dose to target aPTT levels based on nomogram

Pediatric Dosing

IV infusion
- Initial loading dose 75 units/kg given over 10 minutes
- Initial maintenance dose 20 units/kg/hour and adjest per local policy

Special Populations

Pregnancy Rating: C
Lactation risk: Infant risk minimal
Renal Dosing
- No adjustment
Hepatic Dosing
- No adjustment

Contraindications

Allergy to class/drug
33% of patients develop some form of bleeding complication; 2-6% develop major bleeding
Heparin-Induced Thrombocytopenia
See HIT (Heparin-Induced Thrombocytopenia)

Risk Factors for Major Bleeding Complication

Recent surgery or trauma
Renal failure
Alcoholism
Malignancy
Liver failure
Concurrent use of warfarin, fibrinolytics, steroids, or antiplatelet drugs

Pharmacology

Half-life: 1.5 hrs
Metabolism: Hepatic
Excretion: Urine
Mechanism of Action:
- Binds to and activates antithrombin which in turns inactivates factor Xa and thrombin
Anticoagulation effect lasts up to 3hr after stopping infusion
Must give IV (not subq) for acute thromboembolic disease
- Unpredictable anticoagulation effect
- Must monitor with PTT; therapeutic range is 1.5-2.5x normal value

References

Authors:

@@ Line 1: / Line 1: @@
-==Common Indications==
+==General==
+*Type: Anticoagulant
+*Dosage Forms: IV, SC
+*Common Trade Names: Heparin
+==Adult Dosing==
+*See [https://depts.washington.edu/anticoag/home/content/heparin-infusion-guidelines University of Washington pharmacy heparin infusion guidelines]
+===Thromboembolism===
+*Bolus: 80 units/kg IV x 1 (MAX: 5,000 units)
+*Then drip: 18 units/kg/h IV (MAX: 1,000 units/h)
+*Adjust dose to target aPTT levels based on nomogram
-DVT, PE, AFIB, ACS
+==Pediatric Dosing==
+*IV infusion
+**Initial loading dose 75 units/kg given over 10 minutes
+**Initial maintenance dose 20 units/kg/hour and adjest per local policy
+==Special Populations==
+*[[Drug Ratings in Pregnancy|Pregnancy Rating]]: C
+*[[Lactation risk categories|Lactation risk]]: Infant risk minimal
+*Renal Dosing
+**No adjustment
+*Hepatic Dosing
+**No adjustment
-==Bleeding Risk Factors==
+==Contraindications==
+*Allergy to class/drug
+*33% of patients develop some form of bleeding complication; 2-6% develop major bleeding
+*Heparin-Induced Thrombocytopenia
+*See [[HIT (Heparin-Induced Thrombocytopenia)]]
+===Risk Factors for Major Bleeding Complication===
+*Recent surgery or trauma
+*Renal failure
+*Alcoholism
+*Malignancy
+*Liver failure
+*Concurrent use of warfarin, fibrinolytics, steroids, or antiplatelet drugs
-A. Surgery, trauma, or stroke within the previous 14 days.
+==Pharmacology==
+*Half-life: 1.5 hrs
+*Metabolism: Hepatic
+*Excretion: Urine
+*Mechanism of Action:
+**Binds to and activates antithrombin which in turns inactivates factor Xa and thrombin
+*Anticoagulation effect lasts up to 3hr after stopping infusion
+*Must give IV (not subq) for acute thromboembolic disease
+**Unpredictable anticoagulation effect
+**Must monitor with PTT; therapeutic range is 1.5-2.5x normal value
-B. History of peptic ulcer disease, GI bleeding or GU bleeding.
+==See Also==
+*[[Unfractionated heparin reversal]]
+*[[Coagulopathy (main)]]
+*[[Low molecular weight heparin]]
-C. Platelet count less than 150K
+==References==
+<references/>
-D. Age > 70 yrs.
+[[Category:Pharmacology]]
-E. Hepatic failure, uremia, bleeding diathesis, brain metastases.
-*Draw extra blue top prior to starting if concerned about a hypercoaguable state (heparin will interfere with assays)
-==Treatment ==
-A. Bolus - 150 u/kg for PE, and 80-100 u/kg for all other conditions.
-B. Infuse - 15-25 u/kg/hr (high risk --> 15-18 u/kg/hr; low risk --> 22-25 u/kg/hr)
-C. Sliding scale - PTT in 60-80 range..
-PTT Bolus/Hold Adjust Heparin
-<50 70 u/kg 0 Increase 200 u/hr
--59 0 0 Increase 100 u/hr
--80 0 0 No change
--99 0 0 Decrease 100u/hr
->100 0 60min Decrease 200 u/hr
-*If 1st PTT after loading dose is > 100 sec do NOT change the infusion rate unless evidence of bleeding
-D. The PTT should be checked 4-6 hrs after a new bolus or any change in the infusion dose.
-E. Other LABS to check include stool GUIAC qd and CBC (platelets) qd
-Duration: DVT or PE --> 5 days of heparin (even if the INR is therapeutic earlier in hospital course)
-==Source ==
-/22/06; DONALDSON (addapted from Lampe)
-[[Category:Heme/Onc]]