Guidelines for heparin dosage

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Guidelines for heparin dosage – iv

Here are the Haematology department’s guidelines for iv heparin dosage for heparinisation for thrombotic conditions.

Take baseline PT APTT. Give 5,000 iv bolus then start pump at 30,000 units over 24 hours (eg. 30,000 units in 24mls of N saline and set pump at 1ml per hour). Repeat APTT after six hours.

 

APTT ratio Bolus Rate Repeat APTT
APTT Ratio <1.5 5,000 +2,500 units over 24 hrs 6hr-12hr
APTT Ratio 1.5-2.0 Nil +2,500 units over 24 hrs

6hr-12hr

APTT ratio 2.0-3.0 Nil Same dose Next Morning

APTT Ratio 3.0-3.5

Nil -2,500 units over 24 hrs

Next Morning

APTT Ratio 3.5-4.0 Nil Stop for 1hr then -2,500 units over 24 hrs

6hr-12hr

APTT Ratio >4.0

Nil Stop for 2hr then -5,000 units over 24 hrs

6hr-12hr

Guidelines for heparin dosage – SC

Here are the Haematology department’s guidelines for SC heparin dosage for heparinisation for thrombotic conditions.

For S C Heparin 250 iu/kg b.d. [200 for females > 60yrs]. Take specimen four to six hours post injection.

 

 

APTT ratio Dose adjustment Repeat APTT
<1.5 +2,500 units b.d. Next Morning
1.5-2.0 +1.250 units b.d. Next Morning
2.0-3.0 No change Next Morning
3.0-3.5 -1,250 units b.d. Next Morning
3.0-4.0 -2,500 units b.d. Next Morning
>4.0 -5,000 units b.d. Next Morning

(Last reviewed October 2018)