Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Dextromethorphan (DXM) is a common ingredient found in over-the-counter cough suppressants that helps to control coughs. It is a synthetic substance that acts on the brain to reduce the urge to cough.
Related terms
NMDA receptor antagonist: NMDA receptor antagonists are substances that block or inhibit the activity of NMDA receptors in the brain. They can have various effects on cognition, perception, and pain.
Serotonin syndrome: Serotonin syndrome is a potentially life-threatening condition caused by an excess of serotonin in the brain. It can occur when multiple medications or substances that increase serotonin levels are taken together.
Drug tolerance: Drug tolerance refers to the body's decreased response to a drug over time, leading to a need for higher doses to achieve the same effect. In the case of DXM, continuous use in large doses can lead to tolerance and potential abuse.