Short answer: Morphine is the original opioid pain medicine, extracted from the opium poppy, and the standard against which other opioids are measured. It is used for severe pain, including in hospitals, cancer care, and palliative care. It is a Schedule II controlled substance with a high risk of addiction and overdose.
Key takeaways
- What it is: Morphine is an opioid agonist and a Schedule II controlled substance in the US.
- Main uses: Severe pain; palliative care.
- Timing: effects start in about 30 minutes by mouth and last 4 hours (immediate release); 8 to 24 hours (extended release).
- Most dangerous mix: Benzodiazepines (alprazolam, diazepam, clonazepam), which can cause profound sedation, slowed breathing, coma, death.
- Naloxone: it reverses an overdose.
- Dependence risk: High.
- Legal route: only with a prescription from a DEA-registered clinician, filled by a licensed pharmacy.
What is morphine?
Morphine is approved for pain severe enough to require an opioid. It is widely used after surgery, for heart attack pain in hospitals, in cancer care, and in hospice and palliative care, where it also relieves breathlessness at the end of life.
Morphine is turned into active metabolites, morphine-3-glucuronide and morphine-6-glucuronide, which the kidneys clear. In people with kidney disease these build up and can cause sedation, confusion, and seizures, so other opioids are often preferred.
Quick facts
| Fact | Morphine |
|---|---|
| Generic name | Morphine sulfate |
| Brand names | MS Contin, Kadian, Duramorph, Infumorph |
| Drug class | Opioid agonist |
| US legal status | Schedule II, prescription only |
| Approved uses | Severe acute and chronic pain |
| Forms | Tablets, extended-release tablets and capsules, oral solution, injection, suppository |
| Onset | About 30 minutes by mouth; minutes when injected |
| Half-life | 2 to 4 hours |
| Broken down by | Glucuronidation in the liver to active metabolites cleared by the kidneys |
How long does morphine last?
- Starts working: About 30 minutes by mouth
- Effects last: 4 hours (immediate release); 8 to 24 hours (extended release)
- Half-life: 2 to 4 hours
Its half-life is 2 to 4 hours. Urine tests typically detect it for 2 to 3 days.
Timing varies with the dose, the form, how it is taken, liver and kidney function, age, and other drugs taken at the same time.
What are the biggest risks of morphine?
The FDA requires boxed warnings, its strongest, on morphine products, including:
- Morphine exposes users to risks of addiction, misuse, and abuse, which can lead to overdose and death.
- Life-threatening slowed breathing can occur, especially when starting treatment or after a dose increase.
- Accidental ingestion, especially by children, can cause a fatal overdose.
- Use with benzodiazepines or other central nervous system depressants, including alcohol, can cause profound sedation, slowed breathing, coma, and death.
Common side effects include constipation, nausea, vomiting, drowsiness, lightheadedness, sweating, and itching (morphine releases histamine).
Serious risks include slowed breathing, very low blood pressure, severe constipation or bowel blockage, and toxicity in kidney disease.
What should you never mix with morphine?
| Combined with | What happens | Label guidance |
|---|---|---|
| Benzodiazepines (alprazolam, diazepam, clonazepam) | Profound sedation, slowed breathing, coma, death | Boxed warning; avoid unless no alternative |
| Alcohol | Stronger sedation and slowed breathing | Avoid |
| Gabapentin, pregabalin, sleep medicines, muscle relaxants | Additive sedation and breathing problems | Use caution; lower doses |
| Muscle relaxants and anticholinergic drugs | Urinary retention, severe constipation | Use caution |
| MAOIs | Unpredictable, severe reactions | Avoid within 14 days |
| Other opioids | Additive breathing suppression | Avoid unless directed by prescriber |
Check any combination with the DoseUses combination checker or ask a pharmacist.
What are the signs of a morphine overdose, and what should you do?
Morphine overdose causes pinpoint pupils, deep sleepiness, slow or stopped breathing, limp muscles, cold clammy skin, and slow heartbeat. Extended-release morphine can keep releasing drug for hours, so people need monitoring even after naloxone.
If someone may have overdosed
- Call 911 if the person is unresponsive, cannot be woken, has blue or gray lips, or is breathing slowly or not at all.
- Give naloxone (Narcan or a generic nasal spray, sold without a prescription) into one nostril. If there is no response after 2 to 3 minutes, give another dose.
- If you are trained, give rescue breaths. Otherwise place the person on their side so they do not choke.
- Stay with them. Naloxone can wear off before morphine does, so the overdose can return even after the person wakes up.
- Most states have Good Samaritan laws that protect people who call 911 for an overdose from some drug charges.
What is morphine withdrawal like, and how long does it last?
People who take morphine regularly for more than a few weeks become physically dependent, even when they take it exactly as prescribed. Dependence is not the same as addiction, but it means stopping suddenly causes withdrawal.
- 6 to 12 hoursEarly symptomsAnxiety, restlessness, yawning, sweating, runny nose, watery eyes, and muscle aches.
- Days 1 to 3Peak withdrawalDiarrhea, stomach cramps, nausea and vomiting, goosebumps, dilated pupils, fast heartbeat, and strong cravings. Rarely dangerous in healthy adults, but dehydration can be serious.
- Days 5 to 10, then weeksLingering symptomsPoor sleep, low mood, low energy, and cravings can continue for weeks. Tolerance falls quickly, which raises the risk of overdose if use restarts.
See the withdrawal timelines and the full morphine withdrawal guide.
Is morphine legal?
In the United States, morphine is a Schedule II controlled substance. The only legal way to get it is with a prescription from a clinician registered with the Drug Enforcement Administration (DEA), filled by a licensed pharmacy. Depending on state law, that can be a physician, nurse practitioner, or physician assistant.
- Refills: Schedule II prescriptions cannot be refilled. A prescriber can write several prescriptions at once, with dates when each may be filled, for up to a 90-day supply in total.
- Telehealth: federal flexibilities let DEA-registered clinicians prescribe Schedule II to V medicines after a telemedicine visit, without a prior in-person exam, through December 31, 2026. A permanent DEA rule was under final review in late 2026. State rules can be stricter.
- Monitoring: prescribers and pharmacists in most states check a prescription drug monitoring program, a database of controlled-substance prescriptions, before prescribing or dispensing.
Outside the United States
| Country | Status |
|---|---|
| United Kingdom | Class A; prescription only |
| Canada | Schedule I of the Controlled Drugs and Substances Act; prescription only |
| Australia | Schedule 8 controlled drug; prescription only |
| International | Schedule I of the 1961 Single Convention on Narcotic Drugs |
Frequently asked questions about morphine
Is morphine stronger than oxycodone?
No. By mouth, oxycodone is about 1.5 times as potent as morphine by weight. Morphine is the standard used to compare all opioids, expressed as morphine milligram equivalents.
Why is morphine used at the end of life?
Morphine relieves pain and the feeling of breathlessness. At carefully adjusted doses in palliative care it improves comfort, and studies do not show it shortens life when used this way.
Is morphine safe with kidney disease?
Morphine's metabolites build up when the kidneys do not work well, which can cause sedation, confusion, and seizures. Other opioids are usually preferred.
How long does morphine stay in your system?
Its half-life is 2 to 4 hours. Urine tests typically detect it for 2 to 3 days.
Does naloxone reverse morphine?
Yes. Naloxone reverses morphine overdose, but it may need repeat doses for extended-release products.
Sources
- MS Contin (morphine) prescribing information, DailyMed, US National Library of Medicine.
- Information about naloxone and nalmefene, US Food and Drug Administration.
- CDC Clinical Practice Guideline for Prescribing Opioids for Pain, 2022, Centers for Disease Control and Prevention, MMWR.
- Controlled Substance Schedules, DEA Diversion Control Division.
- 21 CFR 1306.12, Refilling prescriptions; issuance of multiple prescriptions (Schedule II), Electronic Code of Federal Regulations.
- Prescribing controlled substances via telehealth, US Department of Health and Human Services.
- BeSafeRx: Your Source for Online Pharmacy Information, US Food and Drug Administration.
- Safe Pharmacy, National Association of Boards of Pharmacy.
This guide summarizes the sourced DoseUses Morphine profile, written from FDA labels, DEA rules, and federal health agencies. It is educational and is not medical advice. Last updated October 5, 2026.
