Opiates include heroin, the most common street narcotic, and its variants. In addition, this large class includes commonly used therapeutic agents such as morphine, codeine, methadone, and other prescription narcotic analgesics. Abstinence symptoms can begin as early as 6 hours after the last dose of heroin or other short-acting opiate. Withdrawal symptoms include anxiety, insomnia, yawning, sweating, and rhinorrhea, followed by dilated pupils, tremor, goose flesh, chills, anorexia, and muscle cramps. About a day after the last dose, pulse, blood pressure, respiration, and temperature may all increase, and diarrhea, nausea, and vomiting can occur. The syndrome, untreated, peaks at 2–3 days and resolves within about 10 days, although mild variable complaints may persist for weeks.