Hydromorphone and Methylnaltrexone interaction
Hydromorphone and Methylnaltrexone: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Hydromorphone (Hydromorphone Hydrochloride) label · effective 2026-07-15
Management of respiratory depression may include close observation, supportive measures, and use of opioid overdose reversal agents (e.g., naloxone, nalmefene), depending on the patient’s clinical status [see Overdosage ( 10 )] .
From the Methylnaltrexone (Relistor) label · effective 2024-05-01
• Other Opioid Antagonists : Potential for additive effect and increased risk of opioid withdrawal; avoid concomitant use.
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.
• Opioid Withdrawal : Consider the overall risk benefit in patients with disruptions to the blood-brain barrier.
Monitor closely for symptoms of opioid withdrawal.
Patients having disruptions to the blood-brain barrier may be at increased risk for opioid withdrawal and/or reduced analgesia.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.