Not Medical Advice: The pill with imprint AN 521 has been identified as Promethazine hydrochloride 25 mg.
Promethazine is used in the treatment of opiate adjunct; sedation; light sedation; nausea/vomiting; allergic reactions (and more).
It works by changing the actions of chemicals in your brain. Promethazine also acts as an antihistamine. It blocks the effects of the naturally occurring chemical histamine in your body.
In the spring and fall, tree, grass, and weed pollens become airborne and can cause sneezing, a runny nose, and itchiness in your nose, throat, and eyes. Doctors call it seasonal allergic rhinitis or allergic conjunctivitis (when it affects the eyes), but most of us just call it hay fever.
Even when the pollen count is high and the breezes are stiff, it's possible to take steps to reduce symptoms of your seasonal allergies. Check out some tips on how to keep your hay fever symptoms at bay at WebMD.