History Taking

TGA Cancels 44 over-the-counter cough suppressant medications

On 28 February 2023 the Therapeutic Goods Administration (TGA) cancelled the registration of 44 over-the-counter cough suppressant medications containing pholcodine following findings that showed pholcodine significantly increase the risk of anaphylaxis in individuals who had taken it in the twelve months prior to the administration of a neuromuscular blocking agent.  In May 2017, de Peter et al reported that six years after the Norwegian government banned the sale of pholcodine the Norwegian population had become significantly less IgE-sensitised and clinically more tolerant to neuromuscular blocking agents such as suxamethonium.[1]


The increasing sensitivity of patients to neuromuscular blocking agents has been associated with obesity and the consumption of pholcodine.  These associations appear to be well established as significant risk factors in anaphylaxis to neuromuscular blocking agents.[2]  In Australia, the research conducted by the TGA identified fifty (50) cases of anaphylaxis, including a death, because of pholcodine sensitisation and neuromuscular blocking agent administration.[3]


One of the major lessons from this is the importance of finding out during our history taking what over-the-counter medications a patient is taking.  This is a subject often overlooked as it is often assumed that over-the-counter medications are harmless or mostly harmless.  We all know that obtaining an accurate medication history from a patient is difficult and adding the over-the-counter medications adds further complexity and this is before we consider illicit drugs and substances, and even dietary supplements when taking a patient history.

The most disturbing aspect of this story is the length of time, twelve months, that the consumption of pholcodine poses a significant level of increased risk of anaphylaxis to the patient scheduled to be given a neuromuscular nerve blocker.  One has to ask what other pharmaceutical surprises lurk out there.


[1] de Pater, G.H., Florvaag, E., Johnasson, S.G.O., Irgens, A, Petersen, M.N.H., and Guttormsen, Six Years Without Pholcodine; Norwegians are Siginificantly Less IgE-Sensitised and Clinically More Tolerant to Neuromuscular Blocking Agents, Allergy, 2017, May; 72(5):813-819. Doi: 10.1111/all.13081.Epub 2016, Dec 12.

[2] Sadleir, P.H.M., Clark, R.C., Goddard, C.E., Day, D., Weightman, W., Middleditch, A., and Platt, P.R., Relationship of Perioperative Anaphylaxis to Neuromuscular Blocking Agents, Obesity, and Pholcodine Consumption: A Case-Control Study, British Journal of Anaesthetics, 2021, May; 126(5):940-948. Doi: 10.1016/j.bja.2020.12.018. Epub 2021 Jan 14.

[3] https://www.tga.gov.au/news/safety-alerts/pholcodine, accessed 2 March 2023