What is the mechanism of action of acetaminophen?

Acetaminophen, commonly known as paracetamol, primarily works by elevating the pain threshold and suppressing the synthesis of prostaglandins in the brain. Prostaglandins are chemicals in the body that promote inflammation, pain, and fever. By inhibiting their synthesis, acetaminophen effectively reduces pain and lowers fever.

The mechanism of action involves interaction with the central nervous system, where acetaminophen increases the pain threshold—meaning that a person may require a higher level of pain stimulus to feel discomfort. This mechanism is notably different from non-steroidal anti-inflammatory drugs (NSAIDs), which also reduce inflammation and pain but through more peripheral actions related to the inhibition of COX enzymes that produce prostaglandins.

While the other options address other types of drug actions, they do not accurately describe acetaminophen. Acetaminophen does not inhibit the immune system, relax smooth muscle cells, or detoxify metabolites in the way suggested in the other options. Understanding the specific action of acetaminophen helps differentiate it from other analgesics and anti-inflammatory medications, highlighting its unique profile in pain management and fever reduction.