I have had post nasal drip for months i am taking nasacort (triamcinolone) i don't thinking it is working anymore what would you recommend taking claritn to?

Consistency: You can add Claritin at any time. I have found that many of my patients who fail to improve on nasal steroids have not been using it consistently. It may take several days for it to even start working. Use the full dose according to the label. If no improvement after a week or two then it's likely that allergy is not the main cause of your symptoms and that should be addressed.