This happens because heroin affect the release of many hormones and neurotransmitters, including those associated with regulating sexual behavior. Ability to reach orgasm is often impaired. Eyelids are droopy, perhaps slowly closing periodically as the person nods off. Irises may be red. Heart rate and blood pressure are normal.
Respiratory rate is very slow.
Skin complexion may be flushed or pale. Numbness to pain. The person may be feeling itchy all over and scratching. Physical effects may include slowed breathing, constricted pupils, and oftentimes nausea and vomit. For example, heroin does not produce a drastic change in blood pressure in healthy individuals.