Heroin side effects have a physical impact on the user’s central nervous system. There are also many psychological side effects of heroin. When a person takes heroin, the initial feeling they experience is a rush or euphoria. The user’s mouth will become dry and they often begin to nod in and out of consciousness. Additionally, their arms and legs will begin to feel very heavy. Users will experience diminished mental capacity and dulled emotions. The effects of this drug typically last 3 to 4 hours from the time of the user’s last dose.

Users experience many negative heroin side effects. The two primary risks are fatal overdose and contraction of HIV/AIDS. It may also cause constricted pupils, nausea, and respiratory depression, which in extreme cases may result in death. When a person takes heroin, it activates brain regions that produce euphoric sensations as well as brain regions that produce physical dependence. These changes in the user’s brain function are what ultimately lead to heroin addiction.

Heroin addicts begin to lose interest in their daily activities. They find that their time is filled with using heroin or that it is focused on obtaining more of the drug. As their use progresses, addicts find that their tolerance continues to increase. This causes them to ingest more and more heroin to achieve the rush or high that they are looking for. As with other drugs of addiction, heroin addicts have trouble keeping their jobs and maintaining personal relationships. Their drug use becomes a number one priority in their lives and their bank accounts tend to diminish. It is not unusual for a heroin addict to spend upwards of $100-$200 dollars a day to feed their addiction.

Heroin side effects include persistent craving for the drug, tolerance (the need for larger and larger doses to get the same results), and painful and dangerous withdrawal. Women who use heroin while pregnant increase their risk of heroin side effects including miscarriage and stillbirth. Infants exposed to heroin in the womb go through withdrawal at birth and exhibit various developmental problems. 
Long-term users of the drug experience health risks such as:

• Abscesses
• Cellulitis
• Collapsed veins
• Hepatitis
• HIV/AIDS
• Infection of the heart lining and valves
• Liver Disease
• Malnutrition
• Pneumonia
• Pulmonary complications

Heroin side effects from withdrawal are extremely painful. The withdrawal symptoms may appear a few hours from when the drug was last administered. Major withdrawal symptoms peak between 48 and 72 hours after the last dose and subside after about a week. Sudden withdrawal by heavily dependent users who are in poor health can be fatal. The user experiences tremendous physical withdrawal symptoms such as:

• Cold flashes with goose bumps
• Diarrhea
• Insomnia
• Kicking movements
• Muscle and bone pain
• Restlessness
• Vomiting