Drug Action: How Opioid Painkillers Work

Opioid drugs are often used to relieve severe pain. Pain signals are transmitted along nerves from the source of pain to the brain. Opioids block the transmission of pain signals in the brain, and thus reduce the sensation of pain.

Before the drug

On reaching the brain, the pain signal is transmitted from one brain cell to the next until it reaches the part of the brain that interprets the signal as pain.

After the drug

Opioid painkillers block transmission of the pain signal in the brain, thereby reducing the sensation of pain.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

Back to top