Benzocaine, Lidocaine, Tetracaine (BLT) is a combination of topical anesthetics used for topical anesthesia and mild pain control, including use during procedures such as endoscopy, surgery, and dental procedures. It can be used for gag reflex suppression as well. The onset of anesthesia is typically less than 1 minute, and the effects last 30 to 60 minutes. Benzocaine, Lidocaine and Tetracaine are more likely than other local anesthetics to cause contact sensitization. The potential for sensitization increases with the duration of contact. These products are not intended for prolonged application time or use.