Skip to main content
Psychedex
Article

Heroin Facts

Opioid; Depressant; Substituted morphinan; Mu-opioid receptor agonist

Description

Heroin (diacetylmorphine) — smack, junk, dope — is a semi-synthetic opioid of the morphinan class. It activates opioid receptors, suppressing pain signals and depressing the brainstem's drive to breathe.[1]

Subjective effects include profound pain suppression, euphoria, heavy sedation, anxiolysis, and a warm enveloping calm. The experience is defined by its onset — intravenous use produces a rapid, overwhelming wave of warmth that erases pain and distress, distinguishing it from the slower build of morphine.

Heroin produces rapid physical dependence and has the narrowest safety margin of any commonly used substance.[2] Tolerance to euphoria develops faster than tolerance to respiratory depression,[3] so dose escalation closes the gap between intoxication and fatal overdose; mortality among untreated dependent people reaches 36.1 per 1000 person-years.[4]

Dose and durationby route · individual sensitivity varies

Smoked(mg)
Threshold< 10 mgLight10 – 25 mgCommon25 – 50 mgStrong50 – 100 mgHeavy100+ mg

Starts in 0.08 – 0.17 minLasts 3 – 5 hoursAfter-effects 1 – 3 hours

Body and dependence

Acute toxicity
Critical
Chronic toxicity
High
Physical dependence
High
Psychological dependence
High
Withdrawal
Severe · medical supervision
Compulsive redosing
High

Tolerance

Builds
Rapid
Fully resets after
10 days
Carries over to
morphine; oxycodone; fentanyl; methadone; hydromorphone; codeine; buprenorphine

Effectslikely at a common dose

Perception
Sleep-transition hallucinations; +5 possible, including Spatial disorientation, Visual acuity suppression
Body
Sedation; Tactile euphoria; Pain suppression; Constipation; Pupil constriction; Bodily heaviness; Body high; Breathing alteration; Muscle relaxation; Physical fatigue; +15 possible, including Respiratory depression, Nausea, Motor control impairment
Thinking
Compulsive redosing urge; Cognitive euphoria; Cognitive fatigue; Cognitive impairment; Information processing suppression; Thought deceleration; +11 possible, including Decision impairment, Analysis suppression, Language suppression
Feeling
Anxiety suppression; Euphoria; +1 possible
Self
Craving; +4 possible, including Communication suppression, Social disconnection
Time
none likely · 3 possible, including Temporal disorientation

Who shouldn't take it

Absolute
Chronic obstructive pulmonary disease; Sleep apnoea; Head injury; Concurrent CNS depressant use; Post-abstinence tolerance loss
Relative
Major depressive disorder; Hepatic impairment; Pregnancy

Combinations62 recorded

Lethal (6)
Benzodiazepines, Barbiturates; GHB, Baclofen; GHB, GBL; Ketamine; Local anesthetics; Tramadol
Dangerous (39)
Antihistamines; Benzodiazepines; Buprenorphine, Kratom; Cannabis, THC; Gabapentin, Pregabalin; MDMA, Amphetamines; Naltrexone; NRIs; Stimulants; THC; 5-HTP, Tryptophan; Alpha-2 adrenergic receptor antagonist; Amphetamines; Anticholinergics; Antipsychotics; Atypical antipsychotics; Buspirone; Caffeine; Cannabis; CBD; Dopamine agonists; DXM; Ephedrine, Pseudoephedrine; Glutamate modulator; and 15 more, see full page
Caution (12)
See full page: psychedex.org/substances/heroin
Not graded (5)
Not listed never means safe.

Seek help immediately if

  • Unresponsive / can't be woken, even to a firm sternal rub
  • Slow, shallow, or stopped breathing
  • Pinpoint pupils
  • Blue/grey lips, fingertips, or skin (cyanosis)
  • Limp body; pale, clammy skin
  • Choking or gurgling sounds ("death rattle")
  • Slow, erratic, or absent pulse

What to do

  1. Try to wake them — shout their name, firm sternal rub
  2. Call emergency services immediately
  3. Administer naloxone if available
  4. Give rescue breaths (or CPR if there is no pulse)
  5. Place them in the recovery position
  6. Stay with them; re-dose naloxone every 2–3 minutes if there is no response
Reversal agent
Naloxone (Narcan) — opioid antagonist. May require repeated doses; its effect can wear off before the opioid does.

With prompt naloxone and rescue breathing, reversal is usually rapid. Because naloxone can wear off before the opioid — especially with long-acting opioids (methadone) or high-potency ones (fentanyl) — a period of monitoring is needed even after the person revives.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Milella MS, D'Ottavio G, De Pirro S, Barra M, Caprioli D, Badiani A (2023) Heroin and its metabolites: relevance to heroin use disorder — Translational Psychiatry doi:10.1038/s41398-023-02406-5
  2. [2]
    ^Lachenmeier DW, Rehm J (2015) Comparative risk assessment of alcohol, tobacco, cannabis and other illicit drugs using the margin of exposure approach — Scientific Reports doi:10.1038/srep08126
  3. [3]
    ^Sim-Selley LJ, Selley DE, Vogt LJ, et al. (2000) Chronic Heroin Self-Administration Desensitizes mu Opioid Receptor-Activated G-Proteins in Specific Regions of Rat Brain — Journal of Neuroscience doi:10.1523/jneurosci.20-12-04555.2000
  4. [4]
    ^Sordo L, Barrio G, Bravo MJ, et al. (2017) Mortality risk during and after opioid substitution treatment: systematic review and meta-analysis of cohort studies — BMJ doi:10.1136/bmj.j1550
Print version
Report an issue