Methylnaltrexone bromide

What is Methylnaltrexone bromide?

• Methylnaltrexone bromide (Relistor) is an opioid antagonist used to relieve constipation caused by treatment with opioids (pain killers similar to morphine).
• It is used in patients with pain caused by cancer or treatment for cancer or by other advanced disease.

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Methylnaltrexone bromide

What are the uses of this medicine?

• Methylnaltrexone bromide (Relistor) is a prescription medicine used to treat constipation in adults that is caused by prescription pain medicines called opioids:
• Relistor tablets and Relistor injection are used to treat constipation caused by opioids in adults with long-lasting (chronic) pain that is not caused by active cancer.
• Relistor injection is used to treat constipation caused by opioids in adults with advanced illness or pain caused by active cancer and who need increases in their opioid dose for comfort care.

How does this medicine work?

• Methylnaltrexone is a selective antagonist of opioid binding at the mu-opioid receptor.
• As a quaternary amine, the ability of methylnaltrexone to cross the blood-brain barrier is restricted.
• This allows methylnaltrexone to function as a peripherally-acting mu-opioid receptor antagonist in tissues such as the gastrointestinal tract, thereby decreasing the constipating effects of opioids without impacting opioid-mediated analgesic effects on the central nervous system (CNS).

Who Should Not Use this medicine ?

This medicine cannot be used in patients who:

• have a bowel blockage (intestinal obstruction) or have a history of bowel blockage.

What drug interactions can this medicine cause?

• Avoid concomitant use of Relistor with other opioid antagonists because of the potential for additive effects of opioid receptor antagonism and increased risk of opioid withdrawal.

Is this medicine FDA approved?

• On April 1, 2008, Progenics and Wyeth announced that Health Canada has approved methylnaltrexone for the treatment of opioid-induced constipation.
• It was later approved by the US FDA on April 24, 2008.

How should this medicine be used?

Recommended dosage: Opioid-Induced Constipation in Adult Patients with Chronic Non-Cancer Pain:

• The recommended dosage of Relistor tablets is 450 mg taken orally once daily in the morning.
• The recommended dosage of Relistor injection is 12 mg administered subcutaneously once daily.

Opioid-Induced Constipation in Adult Patients with Advanced Illness:

• The pre-filled syringe is only for patients who require a Relistor injection dose of 8 mg or 12 mg.
• Use the vial for patients who require other doses of Relistor injection.

Relistor injection: Table below shows the recommended weight-based dose of Relistor injection and the corresponding injection volume.

:Weight-Based Dosing of Relistor Injection and Corresponding Injection Volume for Adult Patients with OIC and Advanced Illness

Weight of Adult Patient	Subcutaneous Dose	Injection Volume
Less than 38 kg	0.15 mg/kg	see below
38 kg to less than 62 kg	8 mg	0.4 mL
62 kg to 114 kg	12 mg	0.6 mL
More than 114 kg	0.15 mg/kg	see below

• Calculate the injection volume for these patients by multiplying the patient weight in kilograms by 0.0075 and then rounding up the volume to the nearest 0.1 mL.

Administration:

• Stay close to a toilet after taking Relistor.
• Stop taking Relistor if you stop taking your prescription opioid pain medicine. Tell your healthcare provider if your pain medicine changes.
• If you take too much Relistor, call your healthcare provider or go to the nearest emergency room right away.
• If you take Relistor for long-lasting (chronic) pain that is not caused by cancer:
• Relistor has been shown to be effective in people who have taken opioid pain medicines for at least 4 weeks to treat long-lasting (chronic) pain not caused by cancer.
• Stop taking other laxatives before you start treatment with Relistor. You may use other laxatives if Relistor does not work after 3 days of treatment.

Tablets:

• Take Relistor tablets 1 time each day with water.
• Take Relistor tablets on an empty stomach at least 30 minutes before your first meal of the day.

Injection (Vials and Pre-filled Syringes):

• Relistor injection is injected under the skin (subcutaneous injection) of the upper arm, stomach-area (abdomen), or thigh.
• Inject Relistor injection exactly as your healthcare provider tells you.
• If you use Relistor injection for long-lasting (chronic) pain that is not caused by cancer:
• Inject 1 dose of Relistor injection each day.
• If you use Relistor injection and are receiving treatment for advanced illness:
• Inject 1 dose of Relistor injection every other day, as needed. You should not inject more than 1 dose of Relistor injection in a 24-hour period.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As Tablets: 150 mg methylnaltrexone bromide.
• As Injection:
• 8 mg/0.4 mL methylnaltrexone bromide in single-dose pre-filled syringe.
• 12 mg/0.6 mL methylnaltrexone bromide in a single-dose pre-filled syringe, or single-dose vial.

This medicine is available in fallowing brand namesː

• Relistor

What side effects can this medication cause?

The most common side effects of this medicine include:

• The most common side effects of Relistor tablets in people with long-lasting (chronic) pain that is not caused by cancer include: stomach-area (abdomen) pain, diarrhea, headache, swelling or a feeling of fullness or pressure in your abdomen, sweating, anxiety, muscle spasms, runny nose, and chills.
• The most common side effects of Relistor injection in people with long-lasting (chronic) pain that is not caused by cancer include: stomach-area (abdomen) pain, nausea, diarrhea, sweating, hot flush, tremor, and chills.
• The most common side effects of Relistor injection in people receiving treatment for their advanced illness include: stomach-area (abdomen) pain, gas, nausea, dizziness, and diarrhea.

Relistor can cause serious side effects, including:

• Tear in your stomach or intestinal wall (perforation)
• Diarrhea that is severe or that will not go away
• Opioid withdrawal

What special precautions should I follow?

• Cases of gastrointestinal perforation have been reported. Consider the overall risk benefit in patients with known or suspected lesions of the GI tract. Monitor for severe, persistent or worsening abdominal pain; discontinue if development of symptoms.
• If severe or persistent diarrhea occurs during treatment, advise patients to discontinue therapy with Relistor and consult their healthcare provider.
• Symptoms consistent with opioid withdrawal, including hyperhidrosis, chills, diarrhea, abdominal pain, anxiety, and yawning have occurred in patients treated with Relistor. Consider the overall risk benefit in patients with disruptions to the blood-brain barrier. Monitor closely for symptoms of opioid withdrawal.

What to do in case of emergency/overdose?

Symptoms of overdosage may include:

• orthostatic hypotension

Management of overdosage:

• If a patient on opioid therapy receives an overdose of Relistor, the patient should be monitored closely for potential evidence of opioid withdrawal symptoms such as chills, rhinorrhea, diaphoresis or reversal of central analgesic effect.
• Base treatment on the degree of opioid withdrawal symptoms, including changes in blood pressure and heart rate, and on the need for analgesia.

Can this medicine be used in pregnancy?

• The limited available data with Relistor in pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriages.
• Advise pregnant women of the potential risk to a fetus.

Can this medicine be used in children?

• Safety and effectiveness of Relistor tablets and injection have not been established in pediatric patients.

What are the active and inactive ingredients in this medicine?

• Active ingredient: methylnaltrexone bromide
• Inactive ingredients (tablets): silicified microcrystalline cellulose, microcrystalline cellulose, sodium lauryl sulfate, croscarmellose sodium, crospovidone, poloxamer 407, stearic acid (vegetable source), colloidal silicon dioxide, edetate calcium disodium, polyvinyl alcohol, titanium dioxide, polyethylene glycol and talc
• Inactive ingredients (injection: vials and pre-filled syringes): sodium chloride USP, edetate calcium disodium USP, glycine hydrochloride. During manufacture, the pH may have been adjusted with hydrochloric acid and/or sodium hydroxide.

Who manufactures and distributes this medicine?

Distributed by:

• Salix Pharmaceuticals, a division of
• Bausch Health US, LLC
• Bridgewater, NJ 08807 USA

Under license from:

• Progenics Pharmaceuticals, Inc.
• Tarrytown, NY 10591 USA

What should I know about storage and disposal of this medication?

Relistor tablets:

• Store Relistor tablets at room temperature between 68° to 77°F (20° to 25°C).
• The bottle of Relistor tablets contains 2 desiccant canisters to help keep your medicine dry.
• Do not remove the desiccant canisters from the bottle.

Relistor injection (Vials and Pre-filled Syringes):

• Store Relistor vials and pre-filled syringes at room temperature between 68° to 77°F (20° to 25°C).
• Do not freeze Relistor vials or pre-filled syringes.
• Keep Relistor vials and pre-filled syringes away from light until you are ready to use them.
• If the contents of a Relistor vial have been drawn into a syringe and you are not able to use the medicine right away, keep the syringe at room temperature for up to 24 hours.

• Dailymed label info on Methylnaltrexone bromide
• FDA Methylnaltrexone bromide

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