Back story: I'm a "textbook" sufferer - Wikipedia's POIS entry could have been written for me.
Last April I saw Dr. Goldmeier in London, who prescribed an antihistamine called Xyzal (levocetirizine dihydrochloride). This belongs to a group that is less likely to cause drowsiness than older antihistamines. A single 5mg. tablet taken an hour or two before sex relieved my symptoms, but left me fairly drowsy the following day - nothing that a few stiff coffees and a siesta couldn't sort out - but it affected my sleep cycle. Whilst it was a big improvement, it wasn't an ideal remedy.
Recently I saw my GP and asked to try a different non-drowsy antihistamine. He prescribed desloratadine 5mg. A single tab, again taken an hour beforehand, relieved my symptoms 100%, and did not leave me at all drowsy - in fact I ran around the next day as if my tail was on fire. Needless to say I am completely delighted! I didn't feel a single side-effect.
As a word of caution I would say that I have only tried this once, but anticipate that it will continue to work as well in the future.
