Protamine for overdose

Antidote Protamine sulfate 1-1.5 mg, IV, for every 100 units heparin subcutaneous within 30 min of overdose, 0.5-0.75 mg for every 100 units heparin subcutaneous if within 30-60 min of overdose, 0.25-0.375 mg for every 100 units heparin subcutaneous if 2 hr have elapsed since overdose, 25-50 mg if heparin was given by IV infusion. 

Heparin overdose (antidote and treatment) IV 1-1.5 mg protamine neutralizes 100 units heparin. Heparin disappears rapidly from circulation, reducing the dosage demand for protamine as time elapses. 

If the overdose amount is unknown, consider an empiric dose of 25-50 mg given over 15 minutes. The anti-Xa lla factor ratios vary for LMWH products and If high, as with a LMW heparinoid (eg, danaparoid), protamine may be ineffective. Anti-factor Xa activity levels and aPTT values are usually not completely reversed, but the hemorrhagic effect may be neutralized. LMWHs have longer half-lives (4-6 hours) and accumulate with renal insufficiency therefore, coagulopathies may persist and protamine should be considered even several hours after the overdose. 

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