## **Core Concept**
The half-life of a drug refers to the time required for the plasma concentration of the drug to reduce by half, which is a critical pharmacokinetic property. Oxytocin is a peptide hormone and neuropeptide, typically involved in social bonding, reproduction, childbirth, and the period after childbirth. Its pharmacokinetics are essential for understanding its clinical applications.

## **Why the Correct Answer is Right**
Oxytocin has a relatively short half-life in the bloodstream, which is crucial for its physiological and clinical effects. The correct half-life of oxytocin is approximately **3-5 minutes**. This short half-life is due to its rapid degradation by various peptidases in the body. The short duration of action is a reason why oxytocin is administered intravenously and often requires continuous infusion for medical applications such as inducing labor or managing postpartum hemorrhage.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option suggests a much longer half-life than what is known for oxytocin, which does not align with its pharmacokinetic profile.
- **Option B:** Similarly, this option also suggests a longer half-life than the established 3-5 minutes for oxytocin.
- **Option D:** This option implies an even shorter half-life than the known duration, which underestimates the pharmacokinetic profile of oxytocin.

## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that due to its short half-life, oxytocin must be administered intravenously for clinical effects such as labor induction, and its effects can be rapidly terminated by stopping the infusion. This makes oxytocin a drug with a very controllable duration of action.

## **Correct Answer:** C. 3-5 minutes.