Phenylephrine strength varies across the listings, commonly 10 mg per tablet in several formulas and 5 mg per tablet in some combined pain‑reliever products.
Some sinus tablets pair the decongestant phenylephrine with the pain reliever acetaminophen (325 mg) to relieve sinus pressure, headaches, and minor aches.
Labels commonly advise consulting a doctor if you have diabetes, high blood pressure, urination problems, thyroid disease, kidney or liver disease, if you are pregnant or nursing, or if you are taking prescription medicines.
Product labels in the results indicate use for adults and for children 12 years and older; one listing specifies 13 years and up.
These 12‑hour allergy tablets state they provide up to 12 hours of symptom relief and report they start working in about one hour.