Methylnaltrexone
Looking up MedlinePlus…
From MedlinePlus, U.S. National Library of Medicine
Dosing in kidney impairment
Dosage in Patients with Renal Impairment The recommended dosage of RELISTOR in patients with moderate and severe renal impairment (i.e., creatinine clearance less than 60 mL/minute as estimated by Cockcroft-Gault) [see Use in Specific Populations] , is shown below by indication: OIC in Adult Patients with Chronic Non - Cancer Pain
RELISTOR tablets: 150 mg once daily in the morning.
RELISTOR injection: 6 mg administered subcutaneously once daily OIC in Adult Patients with Advanced Illness RELISTOR injection: The recommended dosage regimen is one dose every other day, as needed is shown in Table 2 . [See table below.] 38 kg to less than 62 kg 4 mg 0.2 mL 62 kg to 114 kg 6 mg 0.3 mL More than 114 kg 0.075 mg/kg See below* *Calculate the injection volume for these patients by multiplying the patient weight in kilograms by 0.00375 and then rounding up the volume to the nearest 0.1 mL.
Dosage in Patients with Renal Impairment The recommended dosage of RELISTOR in patients with moderate and severe renal impairment (i.e., creatinine clearance less than 60 mL/minute as estimated by Cockcroft-Gault) [see Use in Specific Populations] , is shown below by indication: OIC in Adult Patients with Chronic Non - Cancer Pain
RELISTOR tablets: 150 mg once daily in the morning.
RELISTOR injection: 6 mg administered subcutaneously once daily OIC in Adult Patients with Advanced Illness RELISTOR injection: The recommended dosage regimen is one dose every other day, as needed is shown in Table 2 . [See table below.] 38 kg to less than 62 kg 4 mg 0.2 mL 62 kg to 114 kg 6 mg 0.3 mL More than 114 kg 0.075 mg/kg See below* *Calculate the injection volume for these patients by multiplying the patient weight in kilograms by 0.00375 and then rounding up the volume to the nearest 0.1 mL.
| Table 2: Weight-Based Dosing in Moderate and Severe Renal Impairment 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 | 0.075 mg/kg | See below* |
| 38 kg to less than 62 kg | 4 mg | 0.2 mL |
| 62 kg to 114 kg | 6 mg | 0.3 mL |
| More than 114 kg | 0.075 mg/kg | See below* |
| Table 2: Weight-Based Dosing in Moderate and Severe Renal Impairment 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 | 0.075 mg/kg | See below* |
| 38 kg to less than 62 kg | 4 mg | 0.2 mL |
| 62 kg to 114 kg | 6 mg | 0.3 mL |
| More than 114 kg | 0.075 mg/kg | See below* |
Dosing in liver impairment
Dosage in Patients with Hepatic Impairment OIC in Adult Patients with Chronic Non-Cancer Pain
RELISTOR tablets: The recommended dosage in adult patients with moderate or severe hepatic impairment (Child-Pugh Class B or C) is 150 mg, once daily in the morning [ see Use in Specific Populations].
RELISTOR injection: If considering dose adjustment for patients with severe hepatic impairment, follow the recommendations in Table 3 [see Use in Specific Populations]. [See table below.] 38 kg to less than 62 kg 4 mg 0.2 mL 62 kg to 114 kg 6 mg 0.3 mL More than 114 kg 0.075 mg/kg See below* * Calculate the injection volume for these patients by multiplying the patient weight in kilograms by 0.00375 and then rounding up the volume to the nearest 0.1 mL.
| Table 3: Weight-Based Dosing in Severe Hepatic Impairment of RELISTOR Injection andCorresponding Injection Volume for Adult Patients with OIC and Chronic Non-Cancer Pain | ||
| Weight of Adult Patient | Subcutaneous Dose | Injection Volume |
| Less than 38 kg | 0.075 mg/kg | See below* |
| 38 kg to less than 62 kg | 4 mg | 0.2 mL |
| 62 kg to 114 kg | 6 mg | 0.3 mL |
| More than 114 kg | 0.075 mg/kg | See below* |
Preparation and administration
Prepare this dose
Your numbers for methylnaltrexone. Take vial strength, diluent, and limits from the label below.
Enter a dose to see draw volume, final concentration, and rates.
Important Administration Information
Be within close proximity to toilet facilities once RELISTOR is administered.
Discontinue RELISTOR if treatment with the opioid pain medication is also discontinued.
In adult patients with chronic non-cancer pain and OIC: o Patients receiving opioids for less than 4 weeks may be less responsive to RELISTOR [see Clinical Studies]. o Discontinue all maintenance laxative therapy prior to initiation of RELISTOR. Laxative(s) can be used as needed if there is a suboptimal response to RELISTOR after three days. o Re-evaluate the continued need for RELISTOR when the opioid regimen is changed to avoid adverse reactions. o In patients with chronic non-cancer pain and OIC, take RELISTOR tablets with water on an empty stomach at least 30 minutes before the first meal of the day.
Preparation and Administration of RELISTOR Injection
RELISTOR injection is for subcutaneous use only.
Single-dose pre-filled syringes: Do not remove the pre-filled syringe from the tray until ready to administer.
Inspect RELISTOR injection visually for particulate matter and discoloration prior to administration. RELISTOR injection is colorless to pale yellow. Discard the pre-filled syringe or vial if particulate matter or discoloration is present.
Administer RELISTOR injection subcutaneously in the upper arm, abdomen or thigh. Do not inject at the same spot each time (rotate injection sites).
RELISTOR single-dose vials: Once drawn into the syringe, if immediate administration is not possible, store at ambient room temperature and administer within 24 hours. Discard any unused portion that remains in the vial.
For patient or caregiver instructions for preparation and administration of RELISTOR injection (including recommended specifications for the syringe and needle to be used with the single-dose vial), see Instructions for Use.
Important Administration Information
Be within close proximity to toilet facilities once RELISTOR is administered.
Discontinue RELISTOR if treatment with the opioid pain medication is also discontinued.
In adult patients with chronic non-cancer pain and OIC: o Patients receiving opioids for less than 4 weeks may be less responsive to RELISTOR [see Clinical Studies]. o Discontinue all maintenance laxative therapy prior to initiation of RELISTOR. Laxative(s) can be used as needed if there is a suboptimal response to RELISTOR after three days. o Re-evaluate the continued need for RELISTOR when the opioid regimen is changed to avoid adverse reactions. o In patients with chronic non-cancer pain and OIC, take RELISTOR tablets with water on an empty stomach at least 30 minutes before the first meal of the day.
| Table 1: Weight-Based Dosing of RELISTOR Injection and Corresponding Injection Volume for Adult Patients with OIC and Advanced Illness | ||
| Weight of Adult Patient | SubcutaneousDose | 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. | ||
| Table 2: Weight-Based Dosing in Moderate and Severe Renal Impairment 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 | 0.075 mg/kg | See below* |
| 38 kg to less than 62 kg | 4 mg | 0.2 mL |
| 62 kg to 114 kg | 6 mg | 0.3 mL |
| More than 114 kg | 0.075 mg/kg | See below* |
| Table 3: Weight-Based Dosing in Severe Hepatic Impairment of RELISTOR Injection andCorresponding Injection Volume for Adult Patients with OIC and Chronic Non-Cancer Pain | ||
| Weight of Adult Patient | Subcutaneous Dose | Injection Volume |
| Less than 38 kg | 0.075 mg/kg | See below* |
| 38 kg to less than 62 kg | 4 mg | 0.2 mL |
| 62 kg to 114 kg | 6 mg | 0.3 mL |
| More than 114 kg | 0.075 mg/kg | See below* |
Drug interactions
Check methylnaltrexone against a medication listLabel text (5 paragraphs)
7 DRUG INTERACTIONS • Other Opioid Antagonists : Potential for additive effect and increased risk of opioid withdrawal; avoid concomitant use. ( 7.1 )
7.1 Other Opioid Antagonists 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.
7.2 Drugs Metabolized by Cytochrome P450 Isozymes In healthy subjects, a subcutaneous dose of 0.3 mg/kg of RELISTOR did not significantly affect the metabolism of dextromethorphan, a CYP2D6 substrate.
7.1 Other Opioid Antagonists 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.
7.2 Drugs Metabolized by Cytochrome P450 Isozymes In healthy subjects, a subcutaneous dose of 0.3 mg/kg of RELISTOR did not significantly affect the metabolism of dextromethorphan, a CYP2D6 substrate.
Contraindications
4 CONTRAINDICATIONS RELISTOR is contraindicated in patients with known or suspected gastrointestinal obstruction and patients at increased risk of recurrent obstruction, due to the potential for gastrointestinal perforation [see Warnings and Precautions ( 5.1 )] . Patients with known or suspected mechanical gastrointestinal obstruction and at increased risk of recurrent obstruction. ( 4 , 5.1 )
Safety data
Reported adverse events (FAERS)
Liver injury (LiverTox)
LiverTox has no chapter for methylnaltrexone. Check the label's hepatic warnings.
Pregnancy and lactation
Pregnancy
8.1 Pregnancy Risk Summary The limited available data with RELISTOR in pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriages. There are clinical considerations when RELISTOR is used by pregnant women [see Clinical Considerations]. In animal reproduction studies, no effects on embryofetal development were observed with the administration of intravenous methylnaltrexone bromide during organogenesis in rats and rabbits at doses up to 20 times and 26 times, respectively, the subcutaneous maximum recommended human dose (MRHD) of 12 mg RELISTOR injection per day.
The intravenous doses in rats and rabbits are about 0.5 times and 0.7 times, respectively, the oral MRHD of 450 mg/day [see Data]. Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions The use of RELISTOR during pregnancy may precipitate opioid withdrawal in a fetus due to the immature fetal blood-brain barrier.
Data Animal Data Reproduction studies have been performed with methylnaltrexone bromide administered during the period of organogenesis to rats at intravenous doses up to 25 mg/kg/day (about 20 times the subcutaneous MRHD of 12 mg/day based on body surface area), and did not cause any adverse effects on embryofetal development. In rabbits, intravenous doses of methylnaltrexone bromide up to 16 mg/kg/day (about 26 times the subcutaneous MRHD of 12 mg/day) did not show any embryofetal toxicity. The intravenous doses in rats (25 mg/kg/day) and rabbits (16 mg/kg/day) are about 0.5 and 0.7 times, respectively, the oral MRHD of 450 mg/day based on body surface area.
A pre- and postnatal development study in rats showed no evidence of any adverse effect on pre- and postnatal development at subcutaneous doses of methylnaltrexone bromide up to 100 mg/kg/day (about 81 times the subcutaneous MRHD of 12 mg/day; about 2.2 times the oral MRHD of 450 mg/day).
Breastfeeding (LactMed)
Methylnaltrexone is not marketed in the United States, but is available in other countries. No information is available on the use of methylnaltrexone during breastfeeding. The manufacturer recommends avoiding breastfeeding in mothers taking methylnaltrexone. Based on pharmacokinetic data, the oral absorption of methylnaltrexone appears to be very low. Observe breastfed infants who have been exposed to opioids during pregnancy or postpartum for signs of opioid withdrawal, especially diarrhea.
Supply and cost
Drug shortage status
Recalls (last 24 months)
Therapeutic equivalence (Orange Book)
Price ladder
Not the price at the counterThese are not what a patient pays at the pharmacy counter. They are what pharmacies, health plans, and government buyers pay, before manufacturer rebates. A patient's cost depends on their insurance (copay, coinsurance, or deductible) or the pharmacy's cash price.