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Trade/other name(s): Astramorph PF, Avinza, Duramorph, Infumorph, Kadian, Morphine Sulfate Sustained Release, MS Contin, MSIR, Oramorph SR, Roxanol.

There are other pills or dosage forms that contain morphine mixed with other drugs.

Why would this drug be used?

Morphine is a strong pain reliever that is used to treat moderate to severe pain. It comes in different forms, such as short-acting liquids or tablets, and long-acting (sustained-release) tablets or capsules.

Short and long-acting pain medicines are often used together for severe chronic (long-term) cancer pain. A long-acting pain medicine is given at regular times to provide continuous pain relief for chronic pain, and a quick, short-acting medicine is given when pain “breaks through” the longer-acting medicine. The fast-acting drug is sometimes called a “rescue” medicine.

Because morphine is made in both long-acting and short-acting forms, it can be used for either of these roles. One of morphine’s sustained-release forms may be used for continuous pain relief, and a short-acting form of morphine that relieves pain quickly (often a liquid) may be used as the rescue medicine.

How does this drug work?

Morphine is an opioid pain reliever. It binds to opioid receptors in the brain and central nervous system (CNS), reducing the perception of pain as well as the emotional response to pain.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), thyroid problems, or Addison’s disease (low adrenal function). These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have abdominal pain or any disorder involving slowed or blocked intestines, such as paralytic ileus. People with these problems shouldn’t take morphine. If you’ve had this kind of problem in the past, tell your doctor so that you can be watched in case it comes back.
  • If you have trouble passing urine, a narrow urethra, or if you have an enlarged prostate. Morphine can make it harder to pass urine.
  • If you have ever had a seizure, head injury, or if you have had problems with pressure or a tumor in your head or brain. Morphine can raise your risk of seizures.
  • If you have low blood pressure. Morphine can worsen this.
  • If you are planning to have surgery or anything requiring general anesthesia in the near future. (See also “Precautions.”)
  • If you have asthma, emphysema, chronic bronchitis, sleep apnea, or other serious breathing problems. Morphine can make these worse, and even cause death by stopping your breathing.
  • If you have gallstones, gallbladder disease, or pancreatitis. Morphine can sometimes worsen these problems.
  • If you have serious mental illness or if you have ever had delirium tremens (severe alcohol withdrawal symptoms). You may have more problems on morphine.
  • If you have taken monoamine oxidase inhibitors (MAOIs) within the past 2 weeks (see “Interactions with other drugs”). Morphine can cause slow or shallow breathing, low blood pressure, excitability, seizures, coma, or shock if any MAOI is left in the body.
  • If you drink alcohol or take any medicine that can affect your brain or nervous system. These may worsen the side effects of morphine or cause other problems. In addition, alcohol can dissolve some of the long-acting forms of morphine in the stomach or intestine, which can cause severe side effects (see “Interactions with other drugs”).
  • If you have trouble with addiction, alcohol, or drug abuse now or have had one in the past. Morphine can be habit forming, especially for those who have had problems before.
  • If any family members have or have had an addiction or drug problem. Morphine is sometimes stolen by or for those who are addicted to it or drugs like it.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. There may be an increased risk of harm to the fetus if a woman takes this drug during pregnancy, especially later in pregnancy (see “Precautions” section).
  • If you are breastfeeding. The drug passes into breast milk and can harm the baby.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Buprenorphine (Subutex, Suboxone), butorphanol (Stadol), nalbuphine (Nubain), or pentazocine (Talwin, Talacen) may decrease the effects of morphine or stop its action altogether. This can cause withdrawal symptoms if you have taken the morphine for some time.

Antidepressants of the older MAOI type such as phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), or selegiline (Emsam) may cause slow or shallow breathing, low blood pressure, excitability, seizures, coma, or shock if morphine is given within 2 weeks of the last MAOI dose.

Quinidine (used to treat abnormal heart rhythms and malaria) may increase the amount of morphine in the body and raise the risk of harmful side effects or overdose.

Medicines or substances that slow down the brain or nervous system, such as these, can cause worse side effects if taken with morphine:

  • Anti-anxiety drugs (tranquilizers or sedatives)
  • Sleeping pills
  • Muscle relaxers
  • Barbiturates
  • Anti-seizure medicines
  • Other opioid drugs
  • Anesthetics
  • Tricyclic antidepressants such as amitriptyline (Elavil), nortriptyline (Pamelor), imipramine (Tofranil), desipramine (Norpramin), doxepin (Sinequan), and others Anti-psychotic drugs
  • Certain anti-nausea medicines
  • Certain antihistamines (those that cause sleepiness)
  • Alcohol-containing drugs or beverages, including beer, wine, and mixed drinks

Some of these can cause slowed breathing, low blood pressure, extreme sleepiness, coma, or even death if taken with morphine.

Diuretics (“water pills”) may not work as well while you are taking morphine.

Medicines that contain alcohol can dissolve some of the long-acting forms of this drug too quickly and give the person too much morphine at one time, which can result in serious side effects, overdose symptoms, or even death.

One person who took cimetidine (Tagamet) with morphine experienced sudden confusion, twitching muscles, and stopped breathing.

Check with your doctor, nurse, or pharmacist about whether other medicines, vitamins, herbs, and supplements can cause problems with this medicine.

Interactions with foods

Beverages that contain alcohol, including beer, wine, and mixed drinks, can raise the risk of harmful effects and death if taken while you’re being treated with morphine.

No other serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Morphine is available in a number of forms. It is usually taken as a pill or liquid by mouth. It comes in short-acting forms (which may need to be taken every 3 to 4 hours) and long-acting forms (which are usually taken every 8 to 24 hours; see below). Morphine can also be given by an injection into a vein or around the spinal cord, as a continuous infusion through a pump connected to a vein, or as a rectal suppository.

Take morphine pills or liquid with a full glass of water, with or without food. Make sure to shake the liquid before measuring it carefully using the dropper or spoon that came with the medicine. Be sure that you know your exact dose when using the dropper or spoon. Check with your pharmacist before you take it if you are not certain.

If you are taking a long-acting pill or capsule such as Ora-Morph SR or MS Contin, do not chew, break, crush, split, or dissolve it. Swallow these pills whole with a full glass of water or juice. If you cannot swallow them whole, talk with your doctor or nurse about getting another medicine. Time-release pills contain enough morphine to last for 12 to 24 hours. If they are chewed, split, dissolved, or crushed, the entire dose can be absorbed by the body all at once, causing overdose. This can mean serious complications and even death. Ask your doctor, nurse, or pharmacist if you have other questions about how to safely take your medicines.

Kadian and Avinza are special types of time-release capsules. They are made up of small beads or pellets that dissolve slowly in the body. These capsules can be swallowed whole, or they can be carefully opened and the beads sprinkled on cold applesauce. The applesauce must be swallowed right away, without chewing. Rinse your mouth with water 2 or 3 times afterward in order to wash down and swallow any remaining beads without chewing them. If the applesauce is not eaten right away, flush it down the toilet. Do not save it for later, because its moisture will dissolve the beads and release a full day’s dose of medicine all at once, which can cause overdose.

When taking a suppository, open the package and dip the tip in cold water. If you are right-handed, lie down on your left side, bring your knees up near your chest, and insert the suppository in your rectum about an inch. Stay in this position for about 15 minutes, then get up and wash your hands well.

Your dose of morphine will depend on how much is needed to control your pain. Your doctor may start you on a lower dose and slowly increase it over a few days or weeks. Take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you.

Keep the medicine in a tightly closed container away from heat and moisture and safely away from children, pets, or other people. Medicine that will not be used should be flushed down the toilet as soon as possible.


This medicine can cause drowsiness and lightheadedness. Do not drive, operate machinery, or perform other activities that require alertness until you know how you react to this medicine. If these symptoms last longer than a few days, talk to your doctor.

Morphine can make you feel dizzy or faint, and increase your risk of falling. Be careful getting up, changing position, or walking. Start slowly and hold onto something or someone to keep you steady. If you feel lightheaded or dizzy, it may help to lie down. It is best to have a responsible adult with you for the first few days after starting the morphine and after any increase in dose, until you know how you will respond to it.

Since morphine affects the central nervous system, do not take other drugs or substances that slow down the brain or nervous system such as alcohol, sedatives, muscle relaxers, and sleeping pills unless your doctor tells you to do so (see “Interactions with other drugs”).

Call your doctor right away if you have trouble breathing, get short of breath, get confused, feel very drowsy, or start seeing or hearing things that aren’t there. These may be signs your dose is too high, or you could have gotten an accidental overdose of the medicine.

Tell your doctor or nurse right away if you have trouble passing urine, trouble walking, vision problems, fainting, trouble swallowing, or other problems.

If you are having any kind of surgery or medical procedure, be sure to tell the doctor or dentist in charge that you are using this medicine. Some anesthesia drugs can cause a dangerous drop in blood pressure when used with this drug.

Constipation is a very common side effect of taking opioid pain medicines. While you’re taking methadone, your doctor may advise you to take medicines such as stool softeners, bulk-forming agents, and/or laxatives as needed to have regular (daily) bowel movements. Talk to your nurse or doctor about this when you first start morphine. Drink plenty of fluids throughout the day, and try to eat foods high in fiber such as whole grains, bran, fruits, and vegetables. Call your doctor or nurse right away if you have not moved your bowels in 2 days.

Most cancer pain can be controlled. Tell your cancer team if your medicines do not control your pain, and keep them informed about any side effects you are having. Your cancer team may need to adjust your medicines several times before they find the medicines that work best for you.

If you have chronic (long-term) cancer pain, talk to your doctor about taking your pain medicines on a regular schedule to keep it from worsening. If you wait until the pain is bad, it takes more medicine to get it under control. If pain comes back between doses, talk to your cancer team about changing your medicine or adding an extra one for “breakthrough” pain.

Talk to your doctor or nurse about using the smallest effective dose to reduce side effects and the development of tolerance and physical dependence. Tolerance means that larger doses are needed to get the same pain relief. Physical dependence means that the body goes into withdrawal if drug is suddenly stopped. Both happen normally when strong opioid medicines are taken over several weeks to treat chronic pain. But this is different from addiction, which starts when the drug is taken for pleasure rather than pain relief. Tell your doctor or nurse if you still have pain even though you are taking the medicine as directed. Do not adjust your dose without talking to your doctor or nurse.

Do not stop taking this medicine without talking to your doctor or nurse. When no longer needed, this medicine should be stopped gradually with the help of your doctor. If it is stopped too quickly or the dose reduced too much, you can have withdrawal symptoms such as restlessness, irritability, anxiety, runny nose, watering eyes, yawning, sweating, chills, gooseflesh, aches, nausea, vomiting, diarrhea, poor appetite, high blood pressure, fast heartbeat, and fast breathing.

Using opioid drugs such as morphine during pregnancy, especially near the end of the pregnancy, can cause neonatal opioid withdrawal. This can be life-threatening to a newborn if it’s not recognized and treated.

Acetaminophen or aspirin are often taken along with morphine to increase the pain relief action. It is important to know if any of your other medicines contain either of these drugs. They are in many remedies, and it is easy to accidentally get too much of them. Check with your doctor, nurse, or pharmacist to find out which of these drugs are included in your daily medicines.

This drug is a controlled substance, and may be habit forming. Keep your medicine in a safe place, away from other people, and do not let anyone else take your medicine. A person who has taken opioid medicines such as morphine for a long time often needs large doses for pain relief, while the same amount could quickly kill someone else.

If you think you or someone else may have taken an overdose of morphine, or if someone else has taken even one dose of time-release morphine, get emergency help right away. Symptoms of morphine overdose may include extreme drowsiness, slow heartbeat, slow or irregular breathing, cold clammy skin, or coma. Morphine overdose can cause the heart or breathing to stop. With time-released medicine it can take up to a day for all the medicine to be absorbed, and the person may need to be observed for some time after treatment.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • Constipation*
  • Drowsiness*
  • Sedation*
  • Nausea (more in the first week or so)
  • Dizziness*
  • Dry mouth
  • Headache

Less common

  • Vomiting
  • Changes in mood, such as euphoria (happiness) or depression
  • Mental clouding, confusion (delirium)*
  • Slow or shallow breathing*
  • Low blood pressure, especially when sitting or standing up
  • Stiff muscles
  • Thirst
  • Delayed digestion
  • Trouble swallowing
  • Trouble walking
  • Slow heart rate
  • Withdrawal symptoms if drug is stopped too quickly*
  • Abnormal thinking
  • Abnormal dreams
  • Hiccups


  • Trouble urinating or painful urination
  • Decreased sexual interest
  • Impotence
  • Abnormal ejaculation
  • Stopping of menstrual periods
  • Low white blood cell counts, which can increase risk of infection
  • Low red blood cell counts (anemia), which can cause weakness and fatigue
  • Abnormal blood tests suggesting that the drug is affecting the liver (Your doctor will discuss the importance of this finding, if any.)
  • Dehydration
  • Weight loss
  • Itching
  • Swelling
  • Red eyes
  • Sweating
  • Rash
  • Serious allergic reaction
  • Opioid withdrawal and even death in the newborn if morphine is taken during late pregnancy*
  • Death due to overdose, low blood pressure, slowed breathing, drug interactions, allergic reactions, or other causes*

*See “Precautions” section for more detailed information.

Other side effects not listed above can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984.)

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 06/18/2014
Last Revised: 06/18/2014