Well, since you are a part of the STA-21 program, I don't think it will be an issue....not in flight school, not a problem.
However, you may wish to call these folks to get an official ruling.
POC:
Physical Qualifications
220 Hovey Rd
attn : Code 342
Pensacola , FL 32508
850-452-2257 x 1074 (DSN 922)
Once you get in the program, different rules apply.
First rule is if a FS doesn't prescribe it, don't take it.
NATOPS/NOMI say this: 18.1 NATOPS on Medications
General NATOPS (OPNAVINST 3710.7T, Chapter 8.3.2.5) includes the following statements on medications:
Taking drugs prescribed by competent medical authority shall be considered sufficient cause for recommendation of grounding unless their use is
specifically approved by a flight surgeon, or a waiver for specific drug use has been granted by CHNAVPERS or the Commandant of the Marine Corps. Consideration shall be given to the removal of ground support personnel from critical duties, for the duration of the drug effects, if appropriate. Medications such as antihistamines, antibiotics, tranquilizers,
sleeping pills, etc., shall be discarded if all are not used during the period of medication.
http://navmedmpte.med.navy.mil/nomi/nami/WaiverGuideTopics/pdfs/Waiver Guide - Medications.pdf