Heartburn pills taken by millions can increase the risk of an early death by up to half, scientists warn.

Experts claim they may be responsible for thousands of fatalities globally each year.

The drugs, called proton pump inhibitors, or PPIs, raise the chances of dying from all causes by up to 50 percent compared to other indigestion tablets.

Use has risen because the obesity epidemic has increased cases of acid reflux – the cause of severe heartburn.

The pills are only meant to be taken for a maximum four weeks.

But many patients end up on them for months or even years as doctors dish out repeat prescriptions.

Other studies have linked them with strokes, male infertility and kidney damage.

Scientists behind the latest worrying findings are calling for tougher restrictions on their use.

A team at Washington University School of Medicine in St Louis studied more than 270,000 people to see how many died within five years of being given the drugs.

The results, published in BMJ Open, showed those taking them for a year or more were 50 percent more likely to die from any cause within five years than those given H2 blockers, a different heartburn remedy.

Even short-term use raised the risk by 25 percent, researchers found.

They said for every 500 people taking the pills for a year, there is one extra death.

Given the millions who take PPIs globally this could translate into “thousands of extra deaths every year,” they said.

Lead researcher Dr. Ziyad Al-Aly said: “People have the idea that PPIs are very safe because they are readily available. But there are real risks to taking these drugs, particularly for long periods of time.”

“People get prescribed PPIs for a good medical reason. But then doctors don’t stop it and patients just keep getting refill after refill.”

Experts from Britain’s Royal Statistical Society urged patients not to quit taking PPIs without their doctors’ advice.

They said the excess deaths could be due to underlying illness – not the drugs.