There are no medications to treat this. However, there are options to mask it, and prevent worsening of the condition.
You should wear SPF 60 sunscreen on your face every day. If you are going to be out in the sun for a long period of time, re-apply every 2 hours. This will prevent the collagen in your skin from weakening, which would in turn accentuate the size of your pores. Everyone should be doing this anyway. Sun damage is what causes aging.
Furthermore, there are a multitude of exfoliant creams and face-washes on the market that are believed, by anecdote, to clean out pores and thus reduce their apparent size. However, I know of no true evidence concerning this.
Finally, and perhaps most effectively, cosmetics can reduce the appearance of pores. Though you might think this sounds "gay", try to consult with a cosmetologist in your area for an opinion on what can be done to decrease your pore size.