Methylnaltrexone (oral/injection)

Methylnaltrexone helps relieve constipation that occurs from using opioid medicine. Methylnaltrexone treats constipation while keeping the pain relief effects of the opioid intact.

Methylnaltrexone is prescribed to adults who take opioid medicine for severe chronic pain that is not due to cancer. The methylnaltrexone injection is also intended for adults with advanced illness who are receiving palliative care (treatment aimed at relieving suffering and enhancing quality of life during a serious illness).

Methylnaltrexone may also be used for reasons not mentioned in this medication guide.

Stop using laxatives before you start using methylnaltrexone.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Methylnaltrexone can cause a bowel movement within 30 minutes. Make sure you are near a restroom when you use methylnaltrexone.

Methylnaltrexone oral is taken by mouth.

Take methylnaltrexone tablets on an empty stomach, at least 30 minutes before your first meal of the day.

Take the tablets with a full glass of water.

Methylnaltrexone injection is injected under the skin. A healthcare provider will give you your first dose and may teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand all instructions.

Your healthcare provider will show you where on your body to inject methylnaltrexone. Use a different site each time you give an injection. Do not inject into the same site two times in a row.

Prepare an injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

Each methylnaltrexone injection vial (bottle) or prefilled syringe is for one use only. Throw it away after one use, even if there is still medicine left inside.

Do not use methylnaltrexone more often than once every 24 hours.

Call your doctor if your symptoms do not improve after 3 days. You may use other laxatives after 3 days of treatment with methylnaltrexone.

Store this medicine at room temperature away from moisture, heat, and light. Do not freeze. Keep the tablets in their original container, along with the 2 canisters of moisture-absorbing preservative.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

After you stop using your opioid pain medication, you should also stop using methylnaltrexone.

Methylnaltrexone may cause a perforation (a hole or tear) in your stomach or intestines. Stop using this medicine and seek medical help immediately if you experience severe stomach pain.

While using this medicine, you might have symptoms of opioid withdrawal, including anxiety, sweating, chills, yawning, stomach pain, or diarrhea.

Stop using methylnaltrexone and contact your doctor if you have severe or ongoing diarrhea.

You should not use methylnaltrexone if you have a blockage in your stomach or intestines.

Tell your doctor if you have ever had:

• a stomach ulcer;
• perforation (a hole or tear) in your stomach or intestines;
• kidney disease;
• liver disease; or
• colitis or other intestinal disorder such as Crohn's disease, diverticulitis, or Ogilvie's syndrome.

Tell your doctor if you are pregnant. If you use methylnaltrexone while you are pregnant, your newborn baby could have withdrawal symptoms.

You should not breastfeed while using methylnaltrexone.

Methylnaltrexone is not approved for use by anyone younger than 18 years old.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Methylnaltrexone may cause a perforation (a hole or tear) in your stomach or intestines. Stop using methylnaltrexone and get medical help right away if you have severe stomach pain that gets worse or does not go away.

Methylnaltrexone may cause serious side effects. Stop using methylnaltrexone and call your doctor immediately if you have:

• severe or ongoing diarrhea;
• extreme dizziness, or feeling like you might pass out;
• bloody or tarry stools, coughing up blood, or vomit that looks like coffee grounds;
• new or worsening nausea or vomiting; or
• symptoms of opioid medicine withdrawal--anxiety, sweating, chills, yawning, stomach pain, diarrhea.

Common side effects of methylnaltrexone may include:

• stomach pain, gas, bloating;
• mild nausea or diarrhea;
• headache, muscle spasms;
• dizziness, tremors, feeling anxious;
• runny nose; or
• chills, sweating, or hot flashes.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Usual Adult Dose for Constipation - Drug Induced:

Opioid-Induced Constipation in Patients with Chronic Non-Cancer Pain:-Oral: 450 mg orally once a day in the morning-Parenteral: 12 mg subcutaneously once a dayComments: -Prior to initiation, discontinue all maintenance laxative therapy; laxatives can be used as needed for suboptimal response after 3 days.-Patients should be within close proximity to a bathroom once this drug is administered. -Re-evaluate continued need for this drug when the opioid regimen is changed to avoid adverse reactions. Opioid-Induced Constipation in Patients with Advanced Illness:Parenteral: Weight-based dosing: Administer subcutaneously every other day as needed, but no more frequently than 1 dose in a 24-hour period: Less than 38 kg: 0.15 mg/kg 38 kg to less than 62 kg: 8 mg (0.4 mL) 62 kg to 114 kg: 12 mg subcutaneously (0.6 mL)More than 114 kg: 0.15 mg/kg subcutaneously Comments: To determine injection volume for patients whose weight is less than 38 kg or more than 114 kg: multiply patient weight (kg) by 0.0075 and round up to the nearest 0.1 mLUses: -For the treatment of opioid-induced constipation in adult patients with chronic non-cancer pain or advanced illness who are receiving palliative care, when the response to laxative therapy has not been sufficient.

Take the missed dose as soon as you remember. If it is nearly time for your next scheduled dose, skip the missed dose. Do not take extra medicine to compensate for the missed dose.

Do not use this medicine more than once in a 24-hour period.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

If you have opioid medication in your body, taking too much methylnaltrexone can cause opioid withdrawal symptoms. Common symptoms of withdrawal include yawning, irritability, sweating, chills, vomiting, diarrhea, and body aches.

Do not use any other laxatives that your doctor has not prescribed.

Other drugs may affect methylnaltrexone, including prescription and over-the-counter medicines, vitamins, and herbal products. Inform your doctor about all your current medicines and any medicine you begin or discontinue using.