Sorry to hear you have PA and are taking methotrexate for it. The wedding this weekend, though, sounds like fun. I think a little alcohol once in a great while with methotrexate may be ok. But I would hesitate before I drank 6 beers while taking methotrexate. When I say a little, I'm talking about 1-2. You may want to run it by your doctor before you go--most doctors are fairly reasonable about alcohol. They realize that we have lives, and occassionally a social event that will include alcohol. Methotrexate is so hard on the liver, though, and when combined with alcohol can be devastating. I assume that is with routine alcohol use; don't know for sure.
Even if you decide not to drink, have fun anyway. You can ask the bartender to make interesting non-alcholic drinks and amaze your friends with how much "alcohol" you can tolerate :)
Current dx: Rheumatoid Arthritis
Suspected dx: UCTD/Early Lupus
Current Meds: Enbrel, Plaquenil, Aciphex, Ultracet, Zyrtec, Allavert-D, Zantac, Tylenol PM
Past Meds: Relafen, Vioxx, Mobic, Voltaren, Sulfasalazine, Entocort, Prednisone, Humira, Reglan