Nitrites often are considered a special class of inhalants. Unlike most other inhalants, which act directly on the central nervous system (CNS), nitrites act primarily to dilate blood vessels and relax the muscles. While other inhalants are used to alter mood, nitrites are used primarily as sexual enhancers. Nitrites include cyclohexyl nitrite, isoamyl (amyl) nitrite, and isobutyl (butyl) nitrite and are commonly known as "poppers" or "snappers." Amyl nitrite is used in certain diagnostic procedures and was prescribed in the past to treat some patients for heart pain. Nitrites now are prohibited by the Consumer Product Safety Commission but can still be found, sold in small bottles labeled as "video head cleaner," "room odorizer," "leather cleaner," or "liquid aroma."