Periostat- Interuption of cycle?

Hey bros, a friend of mine whos a couple weeks into his cycle(test/dbol jump start) took a trip to the dentist and was perscribed Periostat after his procedure. I know it's an anti-inflammatory steroid but is it unsafe to continue the cycle?
With the hand-out he got with it, it advises not to mix the drug with certain vitamins. He thought about calling the dentist to ask, but I told him to let me check with you guys first because the dentist is most likely not going to know shit about roids.
If need be, I'll send him to my doc.

Any one with experience?

http://www.rxlist.com/cgi/generic/doxy.htm

I didn't see anything in the side effects section of this webpage about Periostat interacting w/ AS. But it would be best if he asked a Dr...

Just have him call a pharmacist. They will tell him right over the phone whether there is an interaction problem.