Pholcodine has been widely used as an antitussive agent but by 2023 concerns over its association with anaphylaxis in some circumstances meant that it has been withdrawn from sale in many territories.

[4] Following the conclusion of a review of post-marketing safety data by the MHRA, all pholcodine-containing medicines are being recalled and withdrawn from the UK as a precaution.

Pholcodine is slowly biotransformed in the body via oxidation and conjugation to a series of metabolites that are eliminated primarily in the urine.

Adverse effects such as constipation, drowsiness, excitation, ataxia and respiratory depression have been reported occasionally or after large doses.

[11] Administration of pholcodine causes production of antibodies linked with fatalities during surgery, when essential neuromuscular blocking agents (NMBAs) are administered to prevent patient movement under general anaesthesia.

[13] The link was suspected when neighbouring Norway and Sweden were found to have tenfold differences of surgical anaphylaxis deaths.

[16] Conversely, Australian anaesthetists have requested a ban on pholcodine[17] due to the high anaphylaxis rate in the country.

[20] In contrast, the European Medicines Agency's 2012 "Assessment report for Pholcodine containing medicinal products" concludes this: The Committee considered that evidence of an association between pholcodine use and development of NMBA-related anaphylaxis is circumstantial, not entirely consistent and therefore does not support the conclusion that there is a significant risk of cross-sensitisation to NMBAs and subsequent development of anaphylaxis during surgery.