ReviewPaediatric anaesthesia2026
Codeine and Metabolite Concentrations in the Breastfed Neonate.
Review in Paediatric anaesthesia, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed.
- Codeine Toxicity via Breast Milk.Paediatric anaesthesia · 2026Article
- Response: Codeine in Breast Milk: Minimal Transfer, Still Risky for Neonates.Paediatric anaesthesia · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Analgesic effect from codeine is from its metabolite, morphine. Morphine is formed by the O-demethylation of codeine and that enzyme is controlled by the cytochrome P450 2D6. More than 60 alleles in the CYP2D6 gene have been identified. This spectrum of polymorphism can be categorized into four groups: poor (PM), intermediate (IM), normal (NM), and ultra-rapid (UR) metabolizers. Codeine is rarely used in children because of fears that those with the UR genotype may suffer respiratory depression from increased morphine production. There is also concern that postpartum women medicated with codeine and who are UR metabolizers may have enough morphine in breastmilk to cause respiratory depression in a breastfed neonate. A pharmacokinetic compartment model was used to explore this assumption. There are five issues to consider in the pharmacological pathway from maternal ingestion of codeine to neonatal morphine plasma concentration: maternal morphine concentration that is dependent on genotype, milk to plasma concentration ratio, neonatal codeine and morphine exposure from breastmilk, codeine metabolism to morphine in the neonate, and morphine clearance in the neonate. The compartment model confirmed the implausibility of neonatal opioid toxicity from breastfeeding. Currently, short-term maternal use of prescription opioids (other than codeine) is considered safe and infrequently presents a hazard to the newborn. Postpartum women are denied codeine for analgesia and yet predicted neonatal morphine concentrations are lower than 1 μg/L, regardless of genotype. Maternal opioids are used with caution, especially after multiple doses, and neonates younger than 46 weeks postmenstrual age are observed for drowsiness and respiratory depression. The maternal use of codeine requires similar considerations and the current ban on codeine use in postpartum women who are breastfeeding requires review.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.