The Defense Department’s new drug testing policy is raising questions about what a valid prescription is, according to the Navy Times.

The new policy, which took effect May 1, added benzodiazepines and hydrocodone to the list of substances that are screened in urine tests. The program already tests for codeine and morphine. Sailors who test positive for any of these drugs, but have a valid prescription, will not be punished. However, if they use pain medication long after their initial symptoms cleared up, problems can arise, even if the drug is prescribed “as needed,” the article notes. Sailors also can run into problems if they take a pain pill for a different type of pain than what the drug was prescribed for.

If a sailor has a positive urine drug test, the commanding officer or another designated person in the chain of command will investigate how and why the drug was used, according to the article. The sailor’s doctor will explain whether the medication was taken according to instructions, and will make a recommendation. The commanding officer then decides how to proceed.

Sailors who have questions about their prescriptions are advised to consult their primary care manager before taking their medication.

The most recent Defense Department health survey, conducted in 2008, found 12 percent of troops used illicit drugs in the previous month, including prescription drugs, compared with 4 percent in 2005.