The usual recommended dose of methylnaltrexone is based on body weight:
- 6 mg for people who weigh 33 kg to less than 38 kg
- 8 mg for people who weigh 38 kg to less than 62 kg
- 12 mg for people who weight 62 kg to 114 kg
- 18 mg for people who weigh 115 kg to 126 kg
For people who weigh less than 33 kg or more than 126 kg, your doctor will calculate the dose of this medication that is appropriate for you.
Methylnaltrexone is injected once every other day under the skin of the upper arm, abdomen, or thigh.
It is important to use this medication exactly as prescribed by your doctor. If you (or a family member or friend) are injecting this medication, a health care professional will show you how to inject the medication properly. Read the instructions provided in the package insert carefully. If you are not sure how to use this medication, contact your doctor or pharmacist.
It is recommended that you use a different site for each injection. Do not inject into skin that is tender, red, bruised, hard, or has stretch marks or scars. If you are giving the injection to yourself, do not inject into the upper arm. You should be sitting or lying down when you receive this medication. Do not stand up quickly after the injection as you may feel dizzy.
If you do not notice improvement within a week, contact your doctor.
Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.
Store this medication at room temperature, protect it from light, and keep it out of the reach of children. Do not allow it to freeze.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.