What is Methylnaltrexone?
Methylnaltrexone can reduce constipation that is caused by opioid medication. Methylnaltrexone reduces constipation while maintaining the opioid's pain-relieving properties. Adults who are using opioid medicine for severe chronic pain, not due to cancer, will be given methylnaltrexone. Adults with advanced illnesses who are undergoing palliative treatment (treatment to alleviate suffering and improve the quality of life) can also use methylnaltrexone. This medication guide does not list all possible uses of methylnaltrexone.
Side effects of Methylnaltrexone
If you experience any of the following signs of an allergic reaction: difficulty breathing, hives or swelling in your lips, face, throat or tongue. Seek medical assistance immediately. It is possible that methylnaltrexone can cause perforation in your stomach or intestinal tract. If you experience severe stomach pain that is getting worse or won't go away after a few days of using methylnaltrexone, stop taking it and seek medical attention immediately.
The side effects of methylnaltrexone can be serious. If you experience:
- Diarrhea that is severe or persistent
- Feeling dizzy or like you could faint is a common phenomenon.
- Bloody or tarry stool, vomiting blood, or vomit that looks like coffee grounds
- If you have nausea or vomiting, or if the symptoms are worsening or new,
- The symptoms of withdrawal from opioid medicines include anxiety, sweating, chills, yawning, and stomach pain.
Side effects common to methylnaltrexone include:
- Stomach pain, gas, and bloating;
- Mild nausea or diarrhea
- Muscle spasms;
- Dizziness, tremors, feeling anxious;
- Runny nose
- Heat flashes, chills, or sweating
There may be other side effects. For medical advice on side effects, call your doctor. Report potential side effects by calling the FDA at 1-800-FDA-1088.
Similar/related drugs
MiraLAX, Docusate, Colace, Lactulose, Bisacodyl, Polyethylene Glycol 3350, and Amitiza
Warnings
It is possible that methylnaltrexone can cause perforation in your stomach and intestines. If you experience severe stomach pain, stop using the medication and seek medical attention immediately. You may experience symptoms of withdrawal from opioids while using this medication. These include anxiety, sweating or chills, yawning, and stomach pain. If you experience severe diarrhea or a persistent problem, stop using methylnaltrexone. Call your doctor.
Before you take this drug
If you are suffering from a stomach or intestinal blockage, then you should avoid using methylnaltrexone.
If you've ever:
- An ulcer of the stomach
- Perforation in the stomach or intestines (a tear or hole);
- Kidney disease
- Liver Disease
- Colitis and other gastrointestinal disorders such as Crohn’s disease or diverticulitis.
Inform your doctor that you're pregnant. Your newborn may experience withdrawal symptoms if you take methylnaltrexone during pregnancy. Breastfeeding is not recommended while taking methylnaltrexone. Anyone younger than the age of 18 is not allowed to use methylnaltrexone.
How to take Methylnaltrexone?
Stop using laxatives before you start using methylnaltrexone. Read all instructions or guides that accompany your medication and follow the directions as instructed on its prescription label. Within 30 minutes, methylnaltrexone may cause a bowel motion. When using methylnaltrexone, be sure to use it near a toilet. Oral methylnaltrexone is administered by mouth. Do not eat for 30 minutes after taking a methylnaltrexone tablet. The tablets should be taken with water. The injection of methylnaltrexone is administered under the skin. Your healthcare provider may give you your first dosage and teach you to use it properly. Please read and follow all instructions for use that come with your medication. If you don't understand the instructions, talk with your pharmacist or physician. You will be shown by your healthcare provider where to inject the methylnaltrexone. Each time, inject in a new place. Don't inject in the same spot twice. Only prepare an injection when you're ready to administer it. If the medication is cloudy or looks like it has changed color, or if there are particles, do not use it. For new medication, call your pharmacist. The methylnaltrexone vials (bottles) and prefilled syringes are only for single-use. After one usage, throw it out, even if the medicine is still inside. Use methylnaltrexone no more than once per 24 hours. If your symptoms don't improve within 3 days, call your doctor. After 3 days, you can use any laxative. Keep this medication at room temperature, away from heat, moisture, and light. Avoid freezing. Do not freez Take care to abide by local or state regulations regarding how and when to dispose of needles/syringes to avoid punctures, and keep this container out of reach of pets and children. You should stop taking methylnaltrexone after you have stopped using opioid pain medications.
Details on dosage
Usual Adult Dose for Constipation—Drug-Induced:
Constipation Associated with Opioids in Chronic Pain Patients:
Oral: Take 450mg orally in the morning.
Parenteral: 12 mg once daily subcutaneously
Comments:
Prior to initiating, discontinue any laxative maintenance therapy. Laxatives may be needed if the response is not optimal after three days.
Patients should have a nearby bathroom available once the drug has been administered.
To avoid any adverse effects, re-evaluate the need for this medication when changing your opioid regimen.
The Constipation Caused by Opioids in Advanced-Illness Patients:
Subcutaneous: weight-based dosage: administer subcutaneously as required every second day, no more than once in 24 hours.
Less than or equal to 38 kg: 0.15 mg/kg
For 38 kg and less than 62kg: 8 mg (0,4 mL).
Subcutaneous dosing: 62kg to 114kg: 12mg (0.6 mL).
Subcutaneously: More than 114 kg (0.15 mg/kg)
Comment: For patients who weigh less than 38kg or more than 114 kg, multiply the patient's weight in kg by 0.0075. Round up to 0.1 ml.
Uses:
When laxatives have not worked, this medication is used to treat opioid-induced constipation among adult patients who suffer from chronic pain without cancer or are suffering from an advanced disease and receive palliative treatment.
What happens if I miss the dose?
As soon as possible, take the dose you missed. If your next dose is approaching, skip the missed dose. You should not take extra medication to compensate for a missed dose. Use this medication no more than once in 24 hours.
What happens if I overdose?
Call 1-800-222-1222 for poison help or seek immediate medical attention. Withdrawal can occur when you are taking an opioid drug. Yawning, irritability, and sweating are common withdrawal symptoms.
What should be avoided?
Use only the laxatives prescribed by your physician.
Interaction with other drug
Other medications, such as prescription drugs, over-the-counter products, vitamins, and herbal remedies, can affect methylnaltrexone. Inform your doctor of all the medicines you are currently taking and those that you will begin or stop using.
