Hmmmmmmm. Sniffles and slight sore throat. It's that time of the year again!
This should be transferred to the Anticoagulation Forum so more will see it there.
However, Claritin (loratadine) won't affect your INR, according to drug interaction sites online.
Tylenol's website says to consult your doctor before taking Tylenol Allergy Multi-Symptom if you are taking "the blood thinning" drug warfarin. I've taking Extra Strength Tylenol & the PM version before, never had a problem, but I haven't taken more than perhaps 4 capsules a day, and not for long periods. I would check with a doctor first, because the Tylenol product contains a decongestant; many cardiac patients are advised to avoid decongestants. I have not taken a decongestant since my surgery.
You may want to ask your doctor for an Rx for a nasal spray something like fluticasone (Flonase) to prevent symptoms of allergies in the future. Our PCP has Rxed fluticasone for both my husband and me. It's pretty reasonably priced; I pay $15 at Walmart. My husband has his filled at Costco (1 bottle for $15.48); when we picked up his last refill, 2 bottles were in the sack. He started to decline the 2nd bottle, but they said the price on 2 bottles was less than 2 individual refills, so he took them and saved about $9.