Which insulin type typically has a duration of 18-20 hours?

The correct answer is long-acting insulin, which is designed to provide a steady level of insulin over an extended period, typically having a duration of action between 18 to 20 hours. This type of insulin allows for better glycemic control throughout the day and is often administered once a day or as needed. Long-acting insulins, such as glargine or detemir, create a consistent baseline level of insulin in the bloodstream, which is crucial for individuals with diabetes who require long-term management of their blood glucose levels.

In contrast, NPH insulin, while it is an intermediate-acting insulin, has a duration of action typically around 10 to 16 hours. Short-acting insulins provide a quick onset of action but have a shorter duration of effect, generally lasting 3 to 6 hours. Very long-acting insulins, although they can last longer than 24 hours, do not specifically fit into the 18-20 hour range, distinguishing long-acting insulin as the appropriate choice in this context.