What is Pamprin Maximum Pain (acetaminophen, pamabrom, and pyrilamine)? Acetaminophen is a pain reliever and fever reducer. Pamabrom is a diuretic (water pill). Pyrilamine is an antihistamine that reduces the effects of natural chemical histamine in the body. Acetaminophen, pamabrom, and pyrilamine is a combination medicine used to treat the symptoms of premenstrual syndrome (PMS), such as tension, bloating, water weight gain, headache, muscle pain, cramps, and irritability.