How OTC Pain Relievers Work

Over-the-counter (OTC) pain relievers are analgesic medications that are available without a doctor’s prescription. They can help to reduce or control minor to moderate aches and pains. OTC pain relievers also reduce fever and many, but not all of them, decrease inflammation.

Although the two classes of pain relievers, NSAIDs and acetaminophen, both reduce pain and fever, they work in different ways.

Acetaminophen relieves pain by blocking the pain message from reaching the brain. It reduces fever by working directly on brain areas that control temperature. Acetaminophen does not control inflammation.

NSAIDs relieve aches and fever by interfering with the production of prostaglandins, which are compounds that sensitize nerves to feel pain. With fewer prostaglandins circulating, people feel less pain and experience a reduction in symptoms associated with inflammation as well, such as fever, swelling, and redness.

NSAIDs block prostaglandin formation by inhibiting two enzymes responsible for their formation, cyclooxygenases I (COX-1) and II (COX-2).