NCIt definition : A prostaglandin D2 receptor (DP1) antagonist with niacin-induced vasodilation inhibiting
activity. Laropiprant binds to and inhibits the activity of DP1, a G-protein coupled
receptor. Via competing with prostaglandin D2 (PG D2) for binding to DP1, this agent
prevents PG D2-induced vasodilation and increased blood flow. As niacin induces the
synthesis of PG D2, predominantly in the skin, administration of laropiprant may prevent
niacin-induced vasodilation in the skin and facial flushing.;