You may experience the following effects after taking heroin. After using heroin, feelings of pain, hunger or sexual urges are diminished. Breathing, blood pressure and pulse become slower. The pupils of the eyes also get much smaller. As the dose increases, the user feels warm, heavy and sleepy.
Large doses can cause nausea and vomiting.
Breathing becomes very slow, bodily temperature drops, and heartbeat becomes irregular. When breathing becomes slow that it stops altogether, death can occur.