Orphenadrine

**Semantic type:** Pharmacologic Substance

**Definition:** A muscarinic antagonist with muscle relaxant activity. Although the mechanism of action has not been determined, orphenadrine appears to block muscarinic acetylcholine receptors as well as N-methyl-D-aspartate (NMDA) receptors in the central nervous system (CNS). This may interfere with the transmission of nerve impulses from the spinal cord to the muscles and may help relax muscles. In addition, orphenadrine exerts antagonistic effects on histamine H1 receptors.

**Synonyms:** - ORPHENADRINE