Pamprin Maximum Strength Multi-Symptom Caplets, Blue Box, 20 count. Each caplet contains 500 mg Acetaminophen (pain reliever), 25 mg Pamabrom (diuretic) and 15 mg Pyrilamine maleate (antihistamine). Pamprin Maximum Strength Multi-Symptom goes to work with three active ingredients: an antihistamine to relive irritability, a diuretic to fight against bloating and weight gain from water and a pain reliever to alleviate cramps, headaches, backaches and muscular aches.