Generic Name:

Methylnaltrexone

Trade Name:

Relistor

Action:

Peripheral acting opioid antagonist

Indications:

Opioid-induced constipation:

Restricted to patients on stable doses of opioids for at least 3 days without a bowel movement AND have received opioids for at least 2 weeks AND have failed multiple types of laxative therapy

Administration Guidelines:

Usual Dosage Range and Route:

SQ: Dosing is according to body weight: Administer 1 dose every other day. Maximum: 1 dose/24 hours.

< 38 kg: 0.15 mg/kg : round dose up to nearest 2mg (0.1 mL of volume)

38 to < 62 kg: 8 mg

62-114 kg: 12 mg

>114 kg: 0.15 mg/kg: round dose up to nearest 2mg (0.1 mL of volume)

Standard Concentrations:

SQ Injection:12 mg/0.6 mL

Special Considerations:

- Contraindicated in known or suspected mechanical bowel obstruction.

- Severe renal impairment (Cl cr <30 mL/minute): Administer 50% of normal dose.

- End-stage renal impairment (dialysis-dependent): Has not been studied.

- Use beyond 4 months has not been studied. Discontinue if opioids are discontinued.

Precautions and Side Effects:

- Abdominal pain

- Flatulence

- Nausea

- Dizziness

- Diarrhea