Safe to take 1 tablet of benedryl (25 mg active ingredient) with two tablets of nyquil severe?

Not safe: I do not suggest taking these drugs together. Benadryl is an antihistamine. The Doxylamine succinate in NyQuil Severe is also an antihistamine. NyQuil Severe delivers maximum symptom-fighting ingredients and so taking another similar drug is too much and could accentuate possible side effects. I also suggest an routine exam at a medical clinic for your condition.