Update on MHRA safety review of medicines containing pseudoephedrine

Pseudoephedrine is licensed for the symptomatic relief of nasal and sinus congestion in colds, flu, and allergies. It has been used in the UK for decades by millions of people. All pseudoephedrine-containing medicines in the UK are for short term use and taken orally. These come in tablet, capsule, powder, liquid, or syrup form; none of the decongestant nasal sprays authorised in the UK contain pseudoephedrine.

There have been very rare reports of posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) associated with pseudoephedrine. These are very rare conditions that can involve inflammation and/or reduced blood supply to the brain, which are recognised as very rare side effects for pseudoephedrine-containing medicines licensed in the UK.

Following a careful MHRA review of the latest available evidence, including the assessment of cumulative reporting of adverse drug reaction reports, the safety information of all pseudoephedrine-containing medicines will be updated to provide clearer descriptions of these risks and potential risk factors for these conditions for both patients and healthcare professionals.

This decision follows independent advice from the Pharmacovigilance Expert Advisory Group (PEAG) of the Commission on Human Medicines (CHM). The PEAG recommended updates to the Summary of Product Characteristics (SmPC) and the Patient Information Leaflet (PIL) and advised that the MHRA remind healthcare professionals and patients of these risks.

No one should take pseudoephedrine if they have very high blood pressure (hypertension) or hypertension not controlled by their medicines, or if they have severe acute (sudden) or chronic (long-term) kidney disease or kidney failure. It is important that patients speak to their doctor or pharmacist if they are unsure.

Patients who develop symptoms of PRES and RCVS should stop taking pseudoephedrine immediately and seek urgent medical attention. Symptoms include severe headache that develops very quickly or suddenly feeling sick or vomiting, confusion or experiencing seizures or changes in vison.

Dr Alison Cave, MHRA Chief Safety Officer, said:

The neurological conditions of PRES and RCVS have been previously identified as very rare potential side effects associated with pseudoephedrine-containing products.

Following a thorough review of new safety data, product information for all pseudoephedrine-containing medicines will be updated to better describe these very rare risks and the potential risk factors associated with these conditions.

We remind healthcare professionals and patients that pseudoephedrine is for short term use only and should only be used to relieve symptoms of nasal and sinus congestion in colds, flu, and allergies.

If you experience a severe headache that develops very quickly or you suddenly feel sick or are vomiting, confused or experiencing seizures or changes in vison while taking this medicine, stop taking it immediately and seek urgent medical attention. Please report any suspected side effects to our Yellow Card scheme.

To date, the MHRA has received four Yellow Card reports of suspected PRES or RCVS associated with pseudoephedrine. This is in the context of widespread usage with over 4 million packets sold in the UK in 2022 alone. 

Notes to editors

  • Further information is available in the Drug Safety Update.

  • Posterior reversible encephalopathy syndrome (PRES), also known as reversible posterior leukoencephalopathy syndrome (RPLS), is a rare condition in which parts of the brain are affected by swelling, usually as a result of an underlying cause. Someone with PRES may experience headache, changes in vision, and seizures, with some developing other neurological symptoms such as confusion or weakness of one or more limbs. Most patients fully recover from this condition.

  • Reversible cerebral vasoconstriction syndrome (RCVS) is a neurological disorder characterised by a sudden onset of severe headache associated with narrowing of blood vessels that supply blood to the brain (intracranial vessels). On brain imaging the narrowing of the blood vessels can look similar to a “string of beads”. In addition to headaches RCVS can also present as medical emergency with strokes (ischaemic strokes or bleed), seizure or as brain oedema (brain swelling). Usually, the narrowing resolves by itself within three months hence it is called reversible vasoconstriction, and most patients fully recover.

  • The Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for regulating all medicines and medical devices in the UK by ensuring they work and are acceptably safe. All our work is underpinned by robust and fact-based judgements to ensure that the benefits justify any risks. The MHRA is an executive agency of the Department of Health and Social Care.

  • The MHRA reviews reports of suspected side effects via the Yellow Card Scheme, run by the MHRA and the Commission on Human Medicines. The scheme collects and monitors information on suspected safety concerns involving healthcare products through voluntary reporting by the public (including patients, parents and carer givers) as well as from healthcare professionals.

  • The nature of Yellow Card reporting means that reported events are not always proven side effects. Some events may have happened anyway.


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