Which statement correctly describes the onset and duration of oxytocin (Pit) when used as a uterotonic?

Which statement correctly describes the onset and duration of oxytocin (Pit) when used as a uterotonic?

• A. Onset 1-2 minutes IV; duration about 1 hour
• B. Onset 5-10 minutes IV; duration about 3 hours
• C. Onset 30-60 seconds IV; duration about 2 hours
• D. Onset 10-15 minutes IV; duration about 4 hours

Answer: (A)

Oxytocin given by IV acts very quickly because it goes straight into the bloodstream. In standard uterotonic use, contractions begin within about 1–2 minutes after starting the IV infusion. Oxytocin has a short plasma half-life, so once the infusion is stopped, its effects wane relatively quickly, typically within about an hour. That combination—rapid onset with a relatively brief duration after stopping—best matches the statement that onset is 1–2 minutes and the effect lasts about 1 hour. The other timing options imply slower onset or longer duration than is typical for IV oxytocin, which is why they’re less accurate in describing its usual pharmacokinetics.

Oxytocin given by IV acts very quickly because it goes straight into the bloodstream. In standard uterotonic use, contractions begin within about 1–2 minutes after starting the IV infusion. Oxytocin has a short plasma half-life, so once the infusion is stopped, its effects wane relatively quickly, typically within about an hour. That combination—rapid onset with a relatively brief duration after stopping—best matches the statement that onset is 1–2 minutes and the effect lasts about 1 hour.

The other timing options imply slower onset or longer duration than is typical for IV oxytocin, which is why they’re less accurate in describing its usual pharmacokinetics.