What is the estimated half-life of heparin?

What is the estimated half-life of heparin?

• A. 30 minutes
• B. 90 minutes
• C. 3-4 hours
• D. 6 hours

Answer: (B)

Half-life is the time it takes for the plasma concentration to fall by half. For unfractionated heparin given therapeutically, clearance is rapid and mainly hepatic, yielding a typical half-life of about 1.5 hours. So, the best estimate is 90 minutes. A shorter value like 30 minutes would underestimate clearance at standard dosing, while 3–4 hours or 6 hours would be too long for unfractionated heparin—though longer half-lives can be seen with other forms of heparin.

Half-life is the time it takes for the plasma concentration to fall by half. For unfractionated heparin given therapeutically, clearance is rapid and mainly hepatic, yielding a typical half-life of about 1.5 hours. So, the best estimate is 90 minutes. A shorter value like 30 minutes would underestimate clearance at standard dosing, while 3–4 hours or 6 hours would be too long for unfractionated heparin—though longer half-lives can be seen with other forms of heparin.