Revealed: Terrifying side effects of Champix, from seizures to suicidal thoughts – as NHS relaunches controversial stop smoking drug

A ‘game-changer’ anti-smoking pill set to be rolled out on the NHS has been linked to more than 25,000 reports of alarming side effects including seizures, personality changes and suicidal thoughts. 

The UK’s drug watchdog has warned that the testimonies indicate ‘a suspicion’ the drug, called Champix, may be to blame for the ill-effects.  

The daily pill was first marketed in the UK by Pfizer in 2006. 

However, it was withdrawn in 2021 after being found to contain elevated levels of the potentially cancer-causing compound N-nitroso-varenicline.

Now, the drug, which triples the odds of quitting smoking, will again be offered on the health service but manufactured by different pharmaceutical company Teva UK. 

Amanda Pritchard, chief executive of NHS England, this week hailed the medicine (also known as varenicline) a ‘game-changer’ and a major step towards creating a ‘smoke-free generation’.

Yet experts today warned the severity of such side effects should not be underplayed and patients must be monitored for mental health effects. 

The drug reduces cravings for nicotine and also helps with withdrawal symptoms such as feeling irritable or having difficulty sleeping. 

The daily pill was first marketed in the UK by Pfizer in 2006 under the brand name Champix

When used alongside counselling the treatment has been shown to help around one in four people to stop smoking for at least six months.   

The 25,000 side effects are logged through the Medicines and Healthcare products Regulatory Agency (MHRA) yellow card system, set up in the 1960s in the wake of the thalidomide scandal. 

It allows doctors, pharmacists and patients to report adverse reactions believed to be caused by prescription and over-the-counter drugs, implants and alternative medicines.

This can lead to them being reviewed, having warnings added to the label or even being taken off the market.

The MHRA says: ‘It may be difficult to tell the difference between something that has occurred naturally and an adverse reaction. 

‘Sometimes reactions can be part of the condition being treated rather than being caused by a medicine.

‘Many factors have to be considered when assessing whether a medicine has caused a reported adverse drug reaction.’

None of the adverse effects are proven to have been caused directly by varenicline. 

Amanda Pritchard, chief executive of NHS England, this week hailed varenicline a ‘game-changer’ and a major step towards creating a ‘smoke-free generation’

But according to the drug watchdog’s document of adverse reactions for varenicline, some 26,574 reports of reactions have been logged since January 1, 2007. 

Almost half (10,489) of all reports logged cited psychiatric disorders, including 2,853 ‘depressed mood disorders and disturbances’. 

Of the psychiatric disorders, ‘sleep disorders and disturbances’ and ‘suicidal and self-injurious behaviours’ accounted for 1,723 and 1,202 reports respectively.  

Some 4,346 were for gastrointestinal disorders, like nausea and vomiting symptoms (2,357), while 2,659 general disorders were also noted.

These included chest pain, seizures, fatigue and malaise.

Twelve reports of heart failure, six strokes and six subarachnoid hemorrhages — a life-threatening condition that occurs when a blood vessel in the brain bursts — were also logged by the MHRA. 

But the number of adverse reactions has reduced year on year since 2008 in line with prescription levels. 

Just a handful have been recorded since the drug was recalled in 2021. 

Such dramatic adverse reactions, however, have become so common that forum users are also sharing their ‘frightening’ experiences on the drug

Latest NHS Business Service Authority data shows just 73 items of varenicline were dispensed in 2023/24 — a small handful of the 70,235 that were given out two years  prior.

Such dramatic adverse reactions, however, have become so common that forum users are also sharing their ‘frightening’ experiences on the drug.

In one Reddit group with over 164,000 members, one user last month wrote: ‘I’ve been on Champix for a week and a half.

‘Stopped taking it twice a day several days ago when I started getting dizzy, jaw ached and fingers and wrist ached.

‘Then yesterday and this morning had a panic attack. I guess it was a panic attack, woke up, felt dizzy then suddenly couldn’t get enough air to breathe. 

‘I’ve never had this happen before, I live by myself and it really frightened me.’

Another wrote: ‘This is the second time, I’ve been on this medication (five years apart). 

‘This time around, my night terrors wake me in the middle of the night. 

‘The nausea isn’t as bad. Bloating is out of control this time around. [I’m] super tired.’

In a separate thread earlier this year, one also said: ‘I had to stop taking it after a couple weeks. 

‘I started to have horribly violent, extremely vivid dreams. I also got the thought that leaving my wife and newborn child was a great idea.

‘I fought those as long as possible until thoughts of suicide came on very strongly. 

‘Luckily, I was already in therapy and pretty open with my mental state and was able to realize the issue.’

Experts say such reactions are incredibly rare and may also be a result of nicotine withdrawal as patients try to quit smoking. 

Professor Penny Ward, an expert in pharmaceutical medicines at Kings College London, told MailOnline: ‘Mood disturbance and other psychiatric problems can occur as part of nicotine withdrawal when attempting — and  succeeding — in stopping smoking. 

‘In 2013, for example, it looks like there were 673 reported reactions in total among 750,000 patients who took the drug. So adverse reactions are very rare.’

The Organisation for Economic Co-operation and Development 2023 health report showed 12.7 per cent of Brits over the age of 15 smoke cigarettes daily, far higher than the US and New Zealand, the latter of which recently introduced a similar phased smoking ban

She added: ‘Patients with psychiatric disorders, particularly those that have been hospitalised for their illness, are often quite heavy smokers so smoking cessation aids are often prescribed in this population. 

‘Regrettably, smoking related harms — heart and lung disease — are often more common than the relatively rare events reported.

‘So there is also a relative risk benefit balance to be considered given that the benefits of smoking cessation are immediate and potentially long lasting.’

Side effects including depression, suicidal ideation and behaviour are already listed as potential consequences of the drug in leaflets tucked inside its packaging.

‘If you are taking varenicline and develop agitation, depressed mood, changes in behaviour that are of concern to you or your family or if you develop suicidal thoughts or behaviours you should stop taking varenicline and contact your doctor immediately for treatment assessment,’ it says. 

In 2015, the label was also updated after health chiefs identified cases of patients having seizures — among both those with no history of the disorder and with a well-controlled seizure disorder. 

They found the majority of these cases occurred within the first month of treatment. 

Experts also said it is vital that anyone prescribed the drug must receive adequate mental health monitoring.

Dr Leyla Hannbeck CEO of Independent Pharmacies Association told MailOnline: ‘The effectiveness of any smoking cessation product is a result of not only the medicine but the behavioural support which underpins it. 

‘Like many medicines varenicline has side effects which includes nausea, vomiting, and stomach upset, and in some cases anxiety and depression have been reported. 

‘Anyone with such symptoms should discuss with healthcare professional right away. Whether this medicine is appropriate for someone is a matter for the clinician.’

Earlier this year, a 209-page Cochrane Review — involving 75 studies and over 45,000 participants — also found varenicline was more effective than other nicotine replacement therapies and side effects were ‘rare’. 

‘The most common unwanted effect of varenicline is nausea, but this is mostly at mild or moderate levels and usually clears over time,’ it concluded. 

‘People taking varenicline likely have an increased chance of a more serious unwanted effect that could result in going to hospital, however this is still rare.’     

The National Centre for Smoking Cessation and Training’s latest report into the drug also concluded: ‘A number of studies have now been performed and none has found evidence of an increased risk of suicide or suicidal ideation due to varenicline.’ 

Around six million adults in UK – one in eight – smoke and there were more than 400,000 hospital admissions in England attributed to smoking in 2022/23.

Each year the NHS spends £2.5 billion on treating health issues caused by smoking. 

The addictive habit causes almost 90 per cent of lung cancers, and can also trigger tumours in the kidney, pancreas, mouth and stomach, among others.

Inhaling carbon monoxide — found in cigarette smoke — also decreases the ability of blood to carry oxygen, putting a strain on the heart.

Varenicline will be made available to patients in England through NHS Stop Smoking Services in collaboration with pharmaceutical company Teva UK, which is producing a new generic version of the treatment.

The NHS expects 85,000 smokers a year to try the drug and believes it will prevent 9,500 smoking-related deaths in the next five years.