How does acetaminophen reduce pain differently from anti-inflammatory drugs?

Acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) differ significantly in their mechanisms of action and therapeutic effects.

While NSAIDs such as ibuprofen and aspirin function primarily by inhibiting cyclooxygenase (COX) enzymes throughout the body, they effectively reduce inflammation by blocking the synthesis of prostaglandins in peripheral tissues. Because of this, they are potent treatments for inflammatory conditions like rheumatoid arthritis.12

In contrast, acetaminophen exerts only weak effects on COX enzymes and possesses negligible anti-inflammatory activity. Its pain-relieving action is thought to be limited primarily to the central nervous system and involves multiple mechanisms. Research suggests it may modulate pain signaling by activating the endocannabinoid system or interacting with neurotransmitter systems, such as serotonin.132

Due to these differences, acetaminophen is often preferred for patients who cannot tolerate the gastrointestinal side effects associated with the systemic prostaglandin inhibition caused by NSAIDs, though it carries its own risk of liver toxicity with heavy use.13