Medications That Cause Dilated Pupils
Some medicines can affect the muscles that control your pupils and prevent them from getting smaller when light shines in. These meds include:
Atropine (Atropen), which treats problems with heart rhythm, stomach issues, and some types of poisoning
Antihistamines, such as diphenhydramine (Benadryl, Genahist, Naramin, Sominex, Unisom)
Decongestants, such as pseudoephedrine (Afrinol, Sudafed)
Motion sickness and anti-nausea medicines, such as dimenhydrinate (Dramamine) or a scopolamine patch
Parkinson’s medications, such as amantadine (Symmetrel) and carbidopa-levodopa (Sinemet)