Final answer:
The best management step for a 19-year-old with severe menstrual pain not relieved by NSAIDs is to prescribe oral contraceptives. They can help regulate the menstrual cycle and reduce menstrual cramps, thus addressing the pain effectively.
Step-by-step explanation:
The most appropriate next step in the management of a 19-year-old with severe menstrual pain, who has not found relief through the use of nonsteroidal anti-inflammatory drugs (NSAIDs), is C. Oral contraceptives. Oral contraceptives can regulate the menstrual cycle and reduce the severity of menstrual cramps, which could address the nature of her pain if related to dysmenorrhea or a condition like endometriosis. Since her pain is not being managed by ibuprofen, and since her exam is normal, using oral contraceptives is a logical non-invasive step before considering surgical options such as laparoscopy.
Changing to a COX-2 inhibitor would not be the most appropriate step as these medications are similar to NSAIDs. GnRH agonists or continuous medroxyprogesterone are typically reserved for more severe cases that do not respond to oral contraceptives. Laparoscopy is an invasive procedure and usually considered after less invasive treatments have been tried.