allergy symptoms such as a runny nose are best treated with an antihistamine like chlorpheniramine (chlor-trimeton). antihistamines are safe for people with diabetes to use. i would not recommend any products that contain pseudoephedrine or phenylephrine such as sudafed or sudafed pe. these medications may increase blood pressure which can be a concern for someone with diabetes. using pseudoephedrine or phenylephrine for only a couple of days may not be a problem. but avoiding them all together is the safest route.
my mother has diabetes. she currently has allergies and a runny nose. what can she take?