Health Library

Morphine/naltrexone (By mouth)

Morphine Sulfate (MOR-feen SUL-fate), Naltrexone Hydrochloride (nal-TREX-one hye-droe-KLOR-ide)

Treats moderate to severe pain. This medicine contains a narcotic pain reliever.

Brand Name(s):

When This Medicine Should Not Be Used:

How to Use This Medicine:

Long Acting Capsule

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you. An overdose can be dangerous. Follow directions carefully so you do not get too much medicine at one time.
• Swallow the extended-release capsule whole. Do not crush, break, or chew it.
• If you cannot swallow the extended-release capsule, you may open it and pour the medicine into a small amount of applesauce. Stir this mixture well and swallow it without chewing. Do not give this medicine through a nasogastric or gastric tube.
• This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Store the medicine in a safe and secure place. Drop off any unused narcotic medicine at a drug take-back location right away. If you do not have a drug take-back location near you, flush any unused narcotic medicine down the toilet. Check your local drug store and clinics for take-back locations. You can also check the DEA web site for locations. Here is the link to the FDA safe disposal of medicines website: www.fda.gov/drugs/resourcesforyou/consumers/buyingusingmedicinesafely/ensuringsafeuseofmedicine/safedisposalofmedicines/ucm186187.htm

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Do not use this medicine if you are using or have used an MAO inhibitor within the past 14 days.
• Some medicines can affect how morphine/naltrexone works. Tell your doctor if you are using any of the following:
  • Cimetidine, quinidine
  • Benzodiazepine medicine
  • Diuretic (water pill)
  • Phenothiazine medicine
• Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol. Tell your doctor if you are also using buprenorphine, butorphanol, nalbuphine, pentazocine, or a muscle relaxer.
• Do not drink alcohol while you are using this medicine.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, lung or breathing problems (such as asthma or COPD), low blood pressure, adrenal problems, pancreas problems, an enlarged prostate, trouble urinating, gallbladder problems, or stomach or digestion problems. Also tell your doctor if you have a history of depression, head injury, brain tumor, seizures, or drug or alcohol abuse.
• This medicine may cause the following problems:
  • High risk of overdose, which can lead to death
  • Respiratory depression (serious breathing problem that can be life-threatening)
  • Serotonin syndrome (when used with certain medicines)
• This medicine can be habit-forming. Do not use more than your prescribed dose. Call your doctor if you think your medicine is not working.
• Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
• This medicine may make you dizzy, drowsy, or faint. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. Sit or lie down if you feel dizzy. Stand up carefully.
• This medicine may cause constipation, especially with long-term use. Ask your doctor if you should use a laxative to prevent and treat constipation.
• This medicine could cause infertility. Talk with your doctor before using this medicine if you plan to have children.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Anxiety, restlessness, fast heartbeat, fever, sweating, muscle spasms, twitching, nausea, vomiting, diarrhea, seeing or hearing things that are not there
• Blue lips, fingernails, or skin
• Extreme dizziness or weakness, shallow breathing, slow or uneven heartbeat, sweating, cold or clammy skin, seizures
• Severe confusion, lightheadedness, dizziness, fainting
• Severe constipation, stomach pain
• Trouble breathing or slow breathing

If you notice these less serious side effects, talk with your doctor:

• Mild constipation, nausea, or vomiting
• Mild sleepiness or tiredness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024