The deadly conditions behind Sudafed safety review which may see flu remedies pulled from shelves

Health watchdogs are reviewing the safety of some everyday decongestants over potential links to two deadly brain disorders.

Tablets and capsules taken to relieve a blocked nose, including some options made by Sudafed, Nurofen and Day & Night Nurse, contain pseudoephedrine.

In rare cases, this drug can trigger a life-threatening reaction in the brain’s blood vessels called posterior reversible encephalopathy syndrome (PRES) or reversible cerebral vasoconstriction syndrome (RCVS).

The Medicines and Healthcare products Regulatory Agency (MHRA), which polices the safety of drugs used in Britain, has launched a review into a host of over-the-counter medicines that contain the drug.

It comes after bosses at its EU counterpart, the European Medicines Agency (EMA), sparked fears by launching their own review into the safety of the medicines less than a fortnight ago.

But what are the two deadly brain conditions? How can they be treated? And who is most at risk of developing them?

Here’s everything you need to know.

Medicines containing pseudoephedrine have been discovered in rare cases to trigger posterior reversible encephalopathy syndrome (PRES). Signs often include headaches, vision problems and seizures – found in over two thirds of cases – according to the NHS

Medicines containing pseudoephedrine have been discovered in rare cases to trigger reversible cerebral vasoconstriction syndrome (RCVS). A severe 'thunderclap' headache is the hallmark sign of RCVS and it may be the only symptom. But other signs of the condition could also include seizures, vision problems and weakness on one side of the body

Medicines containing pseudoephedrine have been discovered in rare cases to trigger reversible cerebral vasoconstriction syndrome (RCVS). A severe ‘thunderclap’ headache is the hallmark sign of RCVS and it may be the only symptom. But other signs of the condition could also include seizures, vision problems and weakness on one side of the body

What are PRES and RCVS?

The rare conditions both involve reduced blood supply — known medically as ischaemia — to the brain, causing it to swell. 

PRES may develop at any age from infants to the elderly, but dozens of studies have found it most frequently affects adults in their 40s and 50s. It is also slightly more common in women. 

RCVS is most often diagnosed in women between the ages of 20 and 50. 

In younger woman, it can sometimes be associated with the changes that happen after giving birth, during pregnancy or when starting or changing birth control pills. 

PRES predominantly — but not exclusively — affects the back of the brain.

Doctors don’t know exactly what is behind PRES. But seven in 10 sufferers have high blood pressure, which puts pressure on the blood vessels and can cause surrounding brain tissue to swell. 

Meanwhile, RCVS occurs when persistent contraction of the blood vessels – vasoconstriction – causes arteries to narrow. This reduces blood flow and oxygen delivery to the affected area of the brain. 

How is it triggered?

PRES is linked with a swathe of conditions, though most frequently with high blood pressure, eclampsia, severe infection, kidney disease and some autoimmune diseases.

Certain medicines, particularly decongestants like Sudafed and Nurofen, or immunosuppressants and cancer chemotherapy, are also thought to raise the risk.

In rarer cases, it could occur as a side effect of the antibiotic linezolid, scorpion poisoning or after LSD and cocaine use. 

Risk factors associated with RCVS include certain prescription medications, such as anti-depressants, nasal decongestants, nicotine patches and head injuries. 

It could also be triggered by blood and intravenous immunoglobulin transfusions, as well as vasoactive secreting tumours. 

UK and EU health watchdogs are probing the possible decongestant connection after reports of PRES and RCVS among people taking medication containing pseudoephedrine.

What are the tell-tale symptoms?

Signs of PRES often include headaches, vision problems and seizures — found in over two thirds of cases — according to the NHS.

Those suffering from the condition may also experience confusion, weaknesses of one or more limbs, nausea and difficulty when speaking. 

The symptoms of PRES usually come on quickly, in just a matter of hours, and worsen over a period of 12 to 48 hours.

A severe ‘thunderclap’ headache is the hallmark sign of RCVS and it may be the only symptom. 

But other signs can include seizures, vision problems and weakness on one side of the body. 

Some also experience difficulty understanding others when they’re speaking and difficulty speaking themselves. 

Decongestants including Sudafed and Day & Night Nurse might be pulled from shelves or even made prescription-only because of links to the rare but deadly brain disorders

The Medicines and Healthcare products Regulatory Agency (MHRA), which polices the safety of drugs used in Britain, is behind the review. The health watchdog told MailOnline yesterday that cases have been 'very rarely reported with these medicines'

Decongestants including Sudafed and Day & Night Nurse might be pulled from shelves or even made prescription-only because of links to the rare but deadly brain disorders. The Medicines and Healthcare products Regulatory Agency (MHRA), which polices the safety of drugs used in Britain, is behind the review. The health watchdog told MailOnline yesterday  that cases have been ‘very rarely reported with these medicines’

Can it kill? 

In the vast majority of cases of PRES and RCVS, patients recover from their symptoms. 

But in some instances, it can be life-threatening.  

Recent studies also suggest that RCVS and PRES both increase the long-term risk of strokes, raising the risk of death. 

The mortality rate is thought to sit between three and six per cent of all cases of PRES and under five percent of RCVS cases. 

Can it be treated? 

Diagnosis of both PRES and RCVS is difficult.

An MRI, CT scan and angiogram — an X-ray of the blood vessels — may be needed.

But if recognised and treated promptly, PRES usually fully resolves within a week.

Experts often recommend that patient’s blood pressure is reduced by 25 per cent in the first few hours of treatment. 

But PRES may recur in around five to ten per cent of cases, more commonly in patients with uncontrolled hypertension. 

Treatment of RCVS depends on the severity of the condition. 

But it usually involves managing blood pressure, severe headaches, and other complications, such as seizures. 

Fluids are also often administered through an IV drip and migraine treatments, such as aspirin, may also be prescribed. 

When should I see a doctor? 

Anyone thought to have the symptoms of PRES or RCVS should seek medical help immediately.

Severe forms of the condition will need to be treated in hospital. 

Following brain scans, sometimes further investigations may need to be performed. 

According to the NHS, this includes blood tests and a lumbar puncture — a thin needle is inserted between the bones in your lower spine — to rule out other causes of symptoms that may cause similar narrowing of the blood vessels. 

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