They are pills prescribed to millions in the UK to treat heart conditions and anxiety.

But beta blockers may pose a hidden risk to the 7.2 million people living with asthma, an NHS GP has warned.

According to the British Heart Foundation, UK doctors issue more than 50 million prescriptions for beta blockers every year.

However, Dr Sooj, a family doctor with over 250,000 TikTok followers, cautioned that the drugs can interfere with the way asthma medications work—potentially putting some patients at risk during an attack.

Asthma causes symptoms such as wheezing, coughing and chest tightness. 

While generally manageable, it can become life-threatening, when severely inflamed airways make it extremely difficult to breathe.

Asthma UK reports that around 1,200 people die from asthma attacks each year in the UK, while in the US the figure is over 3,500.

In a TikTok, Dr Sooj explained: ‘If you have asthma you need to be cautious and we need to make sure you’re aware of any of the risks and potential complications of taking a beta blocker.’

He continued: ‘The medications we use in an acute asthma attack are called beta agonists—these help to dilate the pipes in your lungs.’

Dr Sooj goes on to explain that these beta agonists—found in many inhalers—relax the muscles in the airways to improve breathing. 

But beta blockers, which are designed to slow the heart rate and reduce blood pressure, can dampen this effect.

‘By doing that it can worsen the symptoms of asthma,’ he said. 

Alongside those with asthma, inhalers are also given to patients with chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema. 

These incurable conditions also cause significant breathing issues and, for this group, beta blockers can also pose a risk. 

The NHS lists asthma and lung disease as conditions patients must inform doctors of before starting beta blockers.

Dr Sooj said: ‘I’ve seen lots of patients with COPD or asthma who have beta blockers and they are completely fine with them.

According to NHS GP Dr Sooj, if you have asthma or chronic obstructive pulmonary disease (COPD) you should think twice before taking them.

‘But this is a discussion that you should be having with your own doctor.’

Dr Sooj added that he still believed beta blockers to be ‘excellent medications’, and explained developments in the drugs that has improved them.

‘We now have cardio selective beta blockers, which… affect the body a bit less.’ 

The new warning follows concerns that a type of beta blocker called propranolol can put patients at risk of ‘toxic overdose’—triggering seizures, depression and even cardiac arrest in high doses. 

Recent research showed the number of prescriptions for propranolol to treat anxiety in the UK doubled between 2003 and 2018.

In theory, by keeping blood pressure low, feelings of panic and anxiety are reduced. 

However some experts have claimed there ‘no evidence’ that drugs are effective for mental health, and that patients often aren’t adequately warned about risk of an overdose.

In a recent letter to The Guardian, pharmacist Christopher Sullivan warned that the drug ‘is associated with significant adverse outcomes’ and urged GPs to exercise ‘extreme caution when prescribing these medicines for anxiety’.

It follows a recent warning by experts that beta blockers can put patients at risk of ‘toxic overdose’

‘Prescribing these medicines for anxiety is not recommended in national evidence-based guidelines,’ he added.

It followed comments from GP Dr Amir Khan, who told the newspaper that propananol had been linked to ‘higher rates of depression’ and warned GPs not to prescribe it to anxious patients who also suffer low mood.

‘If you are taking them long term, you can’t suddenly stop them,’ he added. ‘You need to be weaned off them.’

The risks are not thought to pertain to those taking the medicine for heart problems and other physical issues like migraine—but experts say patients with mental health troubles are vulnerable to either accidentally or purposefully taking an overdose.