In the morphine breakthrough pain preparation described, which preparation is specified as a 10 mg/5 mL solution?

• A. Diphenhydramine solution
• B. Acetaminophen solution
• C. Morphine solution
• D. Ondansetron solution

Answer: (C)

The key idea is that a concentration like 10 mg in 5 mL shows exactly how much drug is in each milliliter, which lets you dose precisely for breakthrough pain. Here, the morphine solution contains 2 mg of morphine per 1 mL (10 mg/5 mL equals 2 mg/mL), so you can measure the exact volume needed to reach the desired dose—for example, 2.5 mL delivers 5 mg, 1 mL delivers 2 mg, and so on. This kind of preparation is specifically used for rapid, titratable relief, matching the needs of breakthrough pain with a predictable, easy-to-measure amount of morphine. The other liquids listed are different drugs (an antihistamine, acetaminophen, and an antiemetic) and would not be described by this morphine concentration, so they don’t fit the described morphine breakthrough pain preparation.