MHRA Tightens Nasal Decongestant Warnings and Adds Finasteride/Dutasteride Psychiatric Risks

London, United Kingdom — 28 May 2026

The Medicines and Healthcare products Regulatory Agency (MHRA) has issued its May 2026 Safety Roundup, highlighting two key updates with direct commercial implications for the UK therapeutics and supplement sectors. Firstly, nasal decongestant sprays containing xylometazoline hydrochloride and oxymetazoline hydrochloride will require strengthened warnings regarding rebound congestion, rhinitis medicamentosa, and tachyphylaxis due to overuse. Brand owners and manufacturers marketing these products must update their Patient Information Leaflets (PILs) and packaging to explicitly advise against use for more than five consecutive days.

The MHRA has observed increasing reports of rebound congestion, where users experience worsening blockage as the decongestant effect recedes. Prolonged use can lead to rhinitis medicamentosa, severe and long-lasting changes to nasal lining, and tachyphylaxis, a rapid reduction in drug efficacy. This necessitates a significant shift in consumer messaging, moving from general 'short-term use' to a specific 'do not use for more than 5 consecutive days' instruction. Healthcare professionals are advised to identify and support patients dependent on these products, with recovery from overuse typically taking up to three months.

What this means for United Kingdom

UK brand owners of over-the-counter (OTC) nasal decongestants must immediately initiate reformulation and relabelling processes to comply with the updated MHRA guidance, specifically the 5-day maximum use warning. This will incur direct costs for packaging redesign and inventory write-offs. Retailers like Boots and Holland & Barrett will expect updated stock with revised PILs; non-compliant products could face delisting. Manufacturers must also prepare for potential shifts in consumer purchasing patterns as the explicit 5-day limit may reduce habitual re-purchases, impacting sales volumes. There is an opportunity for brands to differentiate through alternative, non-pharmacological congestion relief products or by clearly communicating compliance and responsible use.

Separately, the MHRA has reinforced safety warnings for finasteride and dutasteride, primarily used for benign prostatic hyperplasia and hair loss. Updated product information will detail an increased risk of psychiatric side effects, including suicidal ideation, and persistent sexual dysfunction. This follows a comprehensive review of available evidence, leveraging previously introduced UK Finasteride patient cards from 2024. Prescribers are now advised to specifically discuss these risks with patients at the point of prescribing, monitor for symptoms, and advise immediate cessation and medical consultation if psychiatric or severe sexual side effects develop. Dutasteride product information will also be updated as a precautionary measure due to its similar mechanism of action.

The update on finasteride and dutasteride places additional counselling responsibilities on pharmacists and general practitioners across the NHS and private healthcare sectors. Furthermore, the MHRA explicitly contraindicates concomitant use of xylometazoline/oxymetazoline with other oral and nasal sympathomimetic decongestants, including pseudoephedrine and phenylephrine, underscoring a broader regulatory push towards clear, unambiguous product interaction warnings.

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