If it is for the treatment of AF, immediate anticoagulation is not necessary. But, in the treatment of a thromboembolic event, anticoagulation is required immediately to prevent further life-threatening embolism. Alternatively, heparin can be given subcutaneously every 12 hrs. The dose needs to be slightly higher at around 15,000-20,000u every 12 hrs. The injection acts as a depot, with the heparin being released over the next 12 hrs.
Subcutaneous heparin is available as both the sodium and calcium salt.
There seems to be little difference between the two as regards efficacy or adverse effects. IV heparin is always given as the sodium salt. If possible, this should be measured for the patient before any anticoagulation is started, to ensure the patient's coagulation status is normal. The APTT should be checked at least daily while the heparin infusion continues. These include enoxaparin, tinzaparin, dalteparin and certoparin.