Heroin reduces pain, hunger and libido and slows breathing and pulse rate. Heavier doses cause a feeling of warmth and sleepiness. Heavy doses can also lead to nausea and vomiting. Overdoses can cause respiratory failure and death. Long-term heavy use of heroin can lead to a loss of appetite and sex drive, sexual dysfunction, pneumonia and constipation.
Pure heroin is relatively non-toxic but is very addictive.
Psychological and physical dependence are common results of long-term use and can lead to financial, dietary, lifestyle and health problems. Additives in street heroin can cause health problems including collapsed veins, abscesses and tetanus and even damage to the brain and internal organs. Dependent users develop a tolerance and need higher doses to achieve the same effects. Withdrawal symptoms are similar to influenza. Babies born to heroin using mothers may be born dependent on heroin.