Health officials are examining evidence on whether distribution rules of some of the most common cold medicines need to change.

Certain over the counter cold and flu medicines could become prescription only or even banned due to potential links to extremely rare but deadly brain disorders.

Medical regulators are "reviewing available" evidence on whether the drug pseudoephedrine could be related to the fatal conditions and will investigate whether distribution rules need to change, reports the Pharmaceutical Journal.

The decongestant is found in some of the most common cold medicines used by Brits including Benylin, Sudafed, Nurofen cold & flu and Day & Night Nurse. The drug works by narrowing swollen blood vessels in the sinuses which is what causes blocked noses, the Mirror reports.

The review, led by the Medicines and Healthcare products Regulatory Agency (MHPRA) comes after alleged reports of cases of two conditions - which cut off the brain's blood supply - were seen in patients who took pseudoephedrine medicines.

In addition, officials of the European Medicines Agency (EMA) began their own investigation into pseudoephedrine a few weeks ago. This comes "following concerns about the risk of posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS), conditions affecting blood vessels in the brain."

A "small number of cases of PRES and RCVS", although officials didn't confirm how many, linked to people taking pseudoephedrine-containing medicine triggered the review. The two conditions lead to a reduced blood supply to the brain which can cause life-threatening complications and death.

According to the NHS, PRES has a number of symptoms including headaches, vision problems, mental changes, seizures and even swelling on the brain. The most telling symptom of RCVS is a severe "thunderclap" headache.

Pseudoephedrine-containing medicines are already known to have a very small risk of cardiovascular or cerebrovascular diseases - this includes heart attacks and strokes. Warnings about such issues are included in product information leaflets and there are sale restrictions in place on such drugs to stop too large an amount being sold at once.