Morphine Facts
Opioid;
Description
Morphine is a naturally-occurring opioid of the morphinan class. It activates opioid receptors across the brain and spinal cord, suppressing pain and triggering dopamine release in the brain's reward system.[1]
Subjective effects include profound pain suppression, euphoria, sedation, physical warmth, and emotional insulation. The experience is defined by what it removes — pain and distress recede behind an enveloping calm that narrows awareness to the immediate present.
Morphine produces rapid physical dependence, and overdose kills by progressively slowing breathing until it stops.[2][3] Tolerance to pain relief builds faster than tolerance to respiratory suppression, narrowing the gap between an effective and a fatal dose — and tolerance loss after abstinence makes returning to previous doses especially lethal.[4]
Dose and durationby route · individual sensitivity varies
Starts in 10 – 30 minLasts 4 – 6 hoursAfter-effects 2 – 4 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
- 14 days
- Carries over to
- heroin;
oxycodone; hydromorphone; fentanyl; methadone; hydrocodone; codeine; buprenorphine
Effectslikely at a common dose
- Perception
- none likely · 6 possible, including Spatial disorientation, Visual acuity suppression, Visual haze / noise
- Body
- Sedation;
Tactile euphoria; Constipation; Respiratory depression; Spontaneous body sensations; Pain suppression; Pupil constriction; Bodily heaviness; Body high; +16 possible, including Nausea, Dizziness, Motor control impairment - Thinking
- Cognitive euphoria;
Thought deceleration; Cognitive impairment; +11 possible, including Compulsive redosing urge, Information processing suppression, Analysis suppression - Feeling
- Anxiety suppression;
Euphoria; +4 possible, including Anhedonia, Depression - Self
- Craving;
+4 possible, including Communication suppression, Social disconnection - Time
- none likely · 1 possible, including Temporal disorientation
Who shouldn't take it
Combinations62 recorded
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
- Try to wake them — shout their name, firm sternal rub
- Call emergency services immediately
- Administer naloxone if available
- Give rescue breaths (or CPR if there is no pulse)
- Place them in the recovery position
- 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
References
- [1]^Corder G, Castro DC, Bruchas MR, Scherrer G (2018) Endogenous and Exogenous Opioids in Pain — Annual Review of Neuroscience doi:10.1146/annurev-neuro-080317-061522
- [2]^Hill R, Santhakumar R, Dewey W, Kelly E, Henderson G (2020) Fentanyl depression of respiration: Comparison with heroin and morphine — British Journal of Pharmacology doi:10.1111/bph.14860
- [3]^Warner-Smith M, Darke S, Lynskey M, Hall W (2001) Heroin overdose: causes and consequences — Addiction PMID:11487418
- [4]^Avidor-Reiss T, Nevo I, Levy R, Pfeuffer T, Vogel Z (1996) Chronic opioid treatment induces adenylyl cyclase V superactivation. Involvement of Gbetagamma — The Journal of Biological Chemistry PMID:8702909