The Pfizer company has announced FDA approval for an over-the-counter ("OTC") version of its anti-allergy medication, Zyrtec, to be released in January.  I am sure there will be an appropriate amount of hype about how wonderful this is.  It  IS  a good antihistamine however it does produce a significant amount of drowsiness in some persons and therefore is not FAA approved for use while flying.  Claritin and Allegra are also good anti-allergy medicines and do not produce drowsiness, (i.e., are FAA approved).  Allegra remains prescription only and Claritin is available over the counter.  Claritin works pretty well if you take TWO tablets instead of the label directions.  It is available at SAMs as "loratidine" at a very reasonable price.  If you do take Zyrtec, allow 36 hours to elapse from the last dose before resuming crew duty.