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Interaction between methadone and clarithromycin as the suspected cause of an opioid toxidrome
  1. Blair Wallace1,
  2. Daniel Edwardes2,
  3. Christian Subbe3 and
  4. Muhammed Murtaza4
  1. 1Intensive Care, Ysbyty Gwynedd, Bangor, UK
  2. 2Pharmacy, Ysbyty Gwynedd, Bangor, UK
  3. 3Acute Internal Medicine, Ysbyty Gwynedd, Bangor, UK
  4. 4Endocrinology, Ysbyty Gwynedd, Bangor, UK
  1. Correspondence to Dr Blair Wallace; blair_wallace{at}


A 40-year-old patient was admitted through the acute medical take with pleuritic chest pain and rigours. He had a medical history of opiate dependence and was receiving 60 mg of methadone once daily. He was diagnosed with a community-acquired pneumonia and treated with amoxicillin and clarithromycin. After administration of only two concomitant doses of methadone and oral clarithromycin, he developed an opioid toxidrome with type-2 respiratory failure, a decreased level of consciousness and pinpoint pupils. The patient was treated with naloxone and his symptoms improved. Retrospectively, it was suspected that an interaction between clarithromycin and methadone might have contributed to the toxidrome. Respiratory failure has not been previously prescribed for this combination of medication and is of high importance for physicians and pharmacists around the world.

  • drug interactions
  • psychiatry (drugs and medicines)
  • infections
  • drugs: CNS (not psychiatric)
  • palliative care

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  • Contributors BW assessed the patient during his inpatient admission and treated him for his opioid toxicity. BW suggested submitting the article for publication. BW wrote the case presentation and some of the discussion. BW coordinated the drafts and submitted the article. DE was the on-call pharmacist who provided advice for Naloxone therapy during the patient’s admission. He found that interaction was not commonly known about. DE wrote some of the discussion. DE wrote to the patient to get consent. MM saw the patient on his post take ward round. MM suggested BMJ case report as the journal to apply to. He also gave advice on consent and proof read the final draft. CS has been invited to review the paper following feedback from the reviewers. CS has experience with preparing manuscripts for submission. He has kindly reviewed the paper and improved the language and style of language.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.