Try combining medications. I have a similar problem, I recently went to a specialist for this & now I'm taking Clarenex D (a miracle drug, much more effective than claritin), Nasonex, an antihistamine nasal spray (astilin), and singulair. The combination works well for me. The other thing is that cold weather will often make your nose run, if this is just problem outside and/or in the winter that probably all it is.

Medication; it's been scientifically proven, how powerful of medication is the question. I've also found combining acetaminophen (Tylenol or midol) with an NSAID is more effective than an NSAID alone, I used to take midol & ibuprofen during my period it worked alright. I got sick of popping pills all day and I went to my doctor and he put me on 500mg naproxen twice a day, it makes a world of difference. For me the Naproxen & accidimoniphon usually works unless something is aggravating it, like my pants are to tight or something. I generally try to wear either a dress or lose pants during that time of month so it doesn't put to much pressure over my stomach, and I'll often tie a sweatshirt or sweater around my waist to help keep the area warm during the day. If I'm wearing clothes that aggravate my cramps the pain killers I take stop helping, and I guess this is how many people with severe cramps feel no matter what.
If nothing else helps try taking a narcotic pain killer with an NSAID, starting with something relatively mild then using something stronger if you need to. A combination of Oxycodone, or Morphine with Ibuprofen or another NSAID (COMBUNOX = Oxycodone + ibuprofen) will help. Obviously these are very powerful drugs & I'm not your doctor, but drugs which treat severe pain effectively do exist. But before taking Oxycodone for cramps make sure you haven't skipped any simple solution like wearing loser pants.