Heroin is an analgesic opioid formed through the modification of morphine, a natural alkaloid occurring in the seed pods of the opium poppy. Heroin is a very potent and addictive opioid.

Heroin addiction

Heroin can be taken via various routes including:

• Injection is one of the most common routes of administration among heroin users
• The powder form of heroin can be snorted and sniffed and the drug absorbed by the blood vessels in the nose
• Heroin may also be smoked so it is inhaled into the lungs and absorbed into the bloodstream

These methods of delivery all take the chemical directly to the brain.

Effects on the brain

Once the heroin reaches the brain, it is converted into the metabolite morphine which binds to the opioid receptors present in the brain and leads to the effects of the drug, such as euphoria or pain relief.

Repeated use of heroin to obtain these pleasurable feelings can lead to physical dependence on the drug. Over time, the pleasurable effects felt on using a certain dose of heroin are blunted or diminished as a person becomes tolerant of the drug. An addict then feels the need to increase the dose in order to gain the same effects as were previously felt with a lesser dose.

Opioid receptors are present in the lower, back part of the brain or the brain stem and are also associated with adverse side effects of the drug such as suppressed breathing and a decrease in blood pressure.

Acute effects of heroin dosage

After an injection of heroin there are some acute or immediate effects which include:

• Euphoria or high
• Warm and flushed skin
• Dry mouth
• Heaviness in the arms and legs

Delayed effects of heroin

A little after the acute effects subside, delayed effects occur such as:

• Alternate alertness and drowsiness
• Confusion and short term memory loss

Risks of heroin abuse or heroin addiction

Some of the risks associated with heroin addiction include:

• Life threatening overdose
• Transmission of infectious diseases such as HIV/AIDS and hepatitis through needle sharing
• Spontaneous abortion
• Collapsed veins
• Heart infections
• Skin infections
• The formation of abscesses
• Liver and kidney damage
• Respiratory depression and repeated lung infections, including pneumonia
• Withdrawal syndrome on stopping use of the drug. This withdrawal can lead to irritability, pain, loss of sleep, nausea, vomiting, diarrhea, goose bumps, hot and cold flashes and intense craving. Major withdrawal symptoms peak between 48 and 72 hours after the last dose and can take more than a week to subside.
• Negative social impact on family and relationships
• Negative financial impact such as poverty, homelessness

Treatment of heroin addiction

• Clonidine minimizes the symptoms of withdrawal
• Naltrexone is an antagonist of the opioid receptors and counteracts the effects of heroin and other opioids
• Methadone and buprenorphine are less potent opioids that may be prescribed as substitutes in the case of severe addiction, when a person has developed severe withdrawal symptoms after stopping the drug use.
• Counselling and psychiatric help to prevent relapse of the addiction and help in rehabilitation.

Further Reading

• All Heroin Content
• What is Heroin?
• Management of Opioid Addiction
• What is Drug Abuse?

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.