NAPLEX (North American Pharmacist Licensure Examination) Practice Exam 2026 - Free NAPLEX Practice Questions and Study Guide

The Rule of 500 is a quick and easy rule used to estimate the amount of carbohydrates covered by one unit of rapid-acting insulin. This rule is based on the assumption that 500 divided by the total daily dose (TDD) of insulin is the number of grams of carbs covered by 1 unit of rapid-acting insulin. Therefore, option A, 500/TDD, is the correct calculation for estimating the grams of carbs covered by 1 unit of rapid-acting insulin using the Rule of 500.

Option B, 450/TDD insulin, is incorrect because it incorrectly includes the word "insulin" in the calculation. This extra word makes the calculation incorrect and does not align with the Rule of 500.

Option C, Cost of new treatment / Effect of new treatment, is incorrect because it does not relate to the topic of calculating grams of carbs covered by 1 unit of rapid-acting insulin. This option is talking about a completely different concept and does not apply to the given question.

Option D, Cigarette packs/day x years smoked, is also incorrect because it has nothing to do with calculating the grams of carbs covered by 1 unit of rapid-acting insulin. This option is discussing