When the effects are felt depends on the route of ingestion.
When cocaine is sniffed, it enters the bloodstream via the nasal membranes. It then travels to the heart and through the pulmonary circulation (heart-lungs-heart) to the brain. Effects are felt in 2 to 3 minutes.
When the vapours are inhaled by smoking or chasing the dragon (heating on foil), the molecules enter the bloodstream in the lungs and are pumped via the heart to the brain. This route ensures the fastest effects, from 7 to 10 seconds later.
When cocaine is injected directly into a vein, it reaches the brain via the heart and the pulmonary circulation (heart-lungs-heart). Effects are perceivable in 15 to 30 seconds.