**Question:** The following insulin can be given intravenously:

A. Regular insulin
B. NPH insulin
C. Insulin Lispro
D. Insulin Aspart

**Core Concept:** Insulin administration methods

**Why the Correct Answer is Right:** Insulin can be administered intravenously in certain situations, particularly when rapid action and effect are required or when subcutaneous administration is not feasible. The correct options for intravenous administration are:

1. Regular insulin (rapid-acting insulin): It has a short duration of action (lasting 3-5 hours) and is commonly used in emergencies to rapidly lower blood glucose levels.
2. Insulin Lispro (rapid-acting insulin analogue): It is a short-acting insulin analogue with a duration of action similar to regular insulin but is often preferred due to its improved stability and reduced risk of precipitation when mixed with other insulins.

**Why Each Wrong Option is Incorrect:**

3. NPH insulin (intermediate-acting insulin): It has a duration of action of 12-14 hours, which is too long for intravenous administration.
4. Insulin Aspart (rapid-acting insulin analogue): It is a short-acting insulin analogue, similar to insulin Lispro, but its duration of action is shorter (lasting 4-6 hours) and it may not be as suitable for intravenous administration.

**Why Each Wrong Option is Incorrect:**

* NPH insulin is not suitable for intravenous administration due to its long duration of action.
* Insulin Aspart has a shorter duration of action (4-6 hours) compared to regular insulin and insulin Lispro, making it less suitable for intravenous administration.

**Clinical Pearl:** In contrast to the options mentioned above, long-acting insulin preparations like insulin Glargine (basal insulin) and insulin Detemir (basal insulin) are not suitable for intravenous administration due to their long duration of action and cannot be mixed with short-acting insulin due to the risk of precipitation.

**Correct Answer:** Regular insulin and insulin Lispro are suitable for intravenous administration as they have a shorter duration of action (3-5 hours) and can be mixed with short-acting insulin for better glycemic control in emergencies.