Experts are evaluating a very uncommon but potentially severe side effect of nasal decongestants sold on the High Street. 

Nasal sprays are a type of medication that is administered through the nose. They are used to treat various conditions such as allergies, nasal congestion, and sinusitis. Nasal sprays typically contain a liquid medication that is sprayed into the nostrils using a pump or a nozzle. The medication can be a decongestant, antihistamine, steroid, or a combination of these drugs. The sprays work by shrinking swollen blood vessels in the nasal passages, reducing inflammation, and improving breathing. Overuse of nasal sprays can lead to dependence and rebound congestion.

Reviewing products containing pseudoephedrine because they may cause brain-supplying vessels to constrict or spasm, reducing blood flow. 

There is concern that this may result in seizures or even a stroke. 

However, drug regulators emphasize the extremely low likelihood of this happening. 

In addition to warnings for more common side effects, such as headache and dizziness, patient information leaflets accompanying pharmaceuticals already include information about rare risks. 

Experts recommend that anyone with questions about medication consult a physician or pharmacist. All medicines are known to have some side effects.

Individuals use pseudoephedrine to alleviate nasal congestion. It is available in sprays, liquids, and tablets, and is occasionally combined with other medications for coughs, colds, or allergies. 

Through its effect on the blood vessels in the nose, the drug can clear obstructed airways and alleviate congestion. 

The UK-wide review of pseudoephedrine was initiated after French regulators informed the European drugs regulator, the EMA, about a few recent, rare cases.

Two brain blood vessel conditions will be examined by specialists:  and reversible cerebral vasoconstriction syndrome (RCVS) and posterior reversible encephalopathy syndrome (PRES)

RCVS can result in sudden, severe thunderclap headaches that frequently recur over days to weeks. 

Vision blurring, headache, convulsions, and confusion may be symptoms of PRES. 

The Yellow Card scheme, run by the Medicines and Healthcare Products Regulatory Agency, allows citizens of the United Kingdom to report any suspected adverse reactions to medicines (MHRA).

The MHRA reports receiving a very small number of reports in this manner in recent years, including one case of PRES in which the patient recovered and one case of RCVS in which the final result was reported as unknown. The safety of the public is our top priority, according to a representative who stated, "We closely monitor the safety of all medications to ensure that the benefits outweigh the risks." 

We are examining the evidence currently available. We will provide any additional guidance necessary. If you have any questions or concerns about your medication, please consult a healthcare professional. The Royal Pharmaceutical Society (RPS) stated that pseudoephedrine is widely used and that similar medications are evaluated thoroughly before being made available to the public. 

Prof. Claire Anderson, president of the RPS, remarked: "When new risks emerge, patients may become concerned. It is appropriate that they be investigated by the relevant authorities, and we await the results of the EMA and MHRA reviews."