Formulary
Methylnaltrexone bromide: Indications, Dosing, Side Effects and Interactions
Methylnaltrexone bromide is a peripherally acting opioid-receptor antagonist.
MedNext Academy | 3 min read
Methylnaltrexone bromide: Indications, Dosing, Side Effects and Interactions
Methylnaltrexone bromide is a peripherally acting opioid-receptor antagonist.
Drug action
Methylnaltrexone bromide is a peripherally acting opioid-receptor antagonist. It therefore blocks the gastro-intestinal (constipating) effects of opioids without altering their central analgesic effects.
Indications and dose
**Opioid-induced constipation in patients with chronic pain (except palliative care patients with advanced illness)**
- **Adult** (By Subcutaneous Injection): 12 mg once daily if required, to be given as 4-7 doses weekly.
**Adjunct to other laxatives in opioid-induced constipation in palliative care**
- **Adult** (By Subcutaneous Injection): (body-weight 115 kg and above) 150 micrograms/kg once daily on alternate days for maximum duration of treatment 4 months, two consecutive doses may be given 24 hours apart if no response to treatment on the preceding day.
Cautions
Diverticular disease (when active); faecal impaction; gastro-intestinal tract lesions (known or suspected); patients with colostomy; patients with peritoneal catheter
Contraindications
Acute surgical abdominal conditions; gastro-intestinal obstruction
Side effects
Common or very common Abdominal pain; diarrhoea; dizziness; gastrointestinal disorders; nausea; opioid withdrawal-like syndrome; vomiting Overdose Symptoms of overdosage include orthostatic hypotension.
Interactions
**Other interactions (3):**
- The organic cation transporter (OCT)-related drug-drug interaction potential between methylnaltrexone bromide and an OCT inhibitor was studied in 18 healthy subjects by comparing the single-dose...
- The renal clearance of methylnaltrexone bromide was reduced following multiple-dose administration of cimetidine (from 31 L/h to 18 L/h).
- Consequently, no meaningful change in AUC of methylnaltrexone bromide, in addition to C max , was observed before and after multiple-dose administration of cimetidine.
Pregnancy
Manufacturer advises avoid unless essential-toxicity at high doses in animal studies.
Breast feeding
Manufacturer advises use only if potential benefit outweighs risk-present in milk in animal studies.
Hepatic impairment
Manufacturer advises avoid in severe impairment (no information available).
Renal impairment
Dose adjustments If creatinine clearance less than 30 mL/minute, reduce dose as follows: body-weight up to 62 kg, 75 micrograms/kg; body-weight 62-114 kg, 8 mg; body-weight 115 kg and above, 75 micrograms/kg. M See Prescribing in renal impairment .
Medicinal forms
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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