Popular painkillers or non-steroidal, anti-flammatory drugs (NSAIDs) can increase the risk of heart attack or stroke by a third, a study has found.

Researchers from the NHS, Hull York Medical School (HYMS), and the Institute for Clinical Evaluative Sciences in Canada found that patients with heart problems who used NSAIDs, including diclofenac and indomethacin, had a significantly higher risk of serious cardiovascular events compared to patients who did not.

Dr Patricia McGettigan, lead researcher of the study at HYMS said: “NSAIDs provide pain relief for millions of patients with chronic inflammatory disorders. The cardiovascular risk is well described but often overlooked.”

Even OTC drugs such as diclofenac were linked to serious cardiovascular risks, however, other common NSAIDs, including naproxen and low doses of ibuprofen do not appear to increase any risks.

The team of researchers based its results after reviewing 51 large scale studies of NSAIDs conducted in Europe, USA, Canada and Australia.

Dr McGettigan commented: “In choosing which one of the many available NSAIDs to use, patients and doctors would benefit from knowledge of the balance between benefit and harm for individual NSAIDs.”

Many people use NSAIDs in both OTC and prescription form for pain relief and for their anti-inflammatory effects to treat pains and aches.

In 2010, GPs prescribed 17 million NSAIDs in England alone, accounting for one in three people in the country. Of these, nearly 6 million were for diclofenac, 5 million were for ibuprofen and 3 million for naproxen, all of which can be bought without prescription.

Pregnant women have been told not to take ibuprofen after new research claimed it can more than double the risk of miscarriage.

The Canadian Medical Association Journal said that the popular painkiller can increase the risk of miscarriage by 2.4 times if taken in the first 20 weeks of pregnancy.

The report stated: “Women who were exposed to any type and dosage of non-aspirin NSAID during early pregnancy were more likely to have a spontaneous abortion.”

Clinicians discovered that 7.5% (352) of 4,705 miscarriage cases were linked to a dose of nonsteroidal anti-inflammatory drugs (NSAIDs) and 2.6% of 47,050 women who did not lose their babies had taken the same drugs.

However, it has also been claimed that women may take painkillers after suffering early signs of miscarriage where no connection has been found to the drug.

Dr Virginia Beckett, spokesman for the Royal College of Obstetricians and Gynaecologists, added: “This study adds to the research base surrounding miscarriage however, it does not look at other factors which may increase a woman’s chance of having a miscarriage such as smoking and weight gain."

Previous research has suggested that NSAIDs, such as ibuprofen containing naproxen and diclofenac, may increase the risk of miscarriage because they reduce the production of vital chemicals called prostaglandins, which are necessary to implant fertilised eggs in the womb.

The findings support NHS advice that pregnant women should use paracetamol as a form of pain relief, particularly in the first and final trimesters of their pregnancies.

Janet Fyle, Professional Policy Adviser at the Royal College of Midwives, said: “We need to advise women, as midwives often do, to avoid buying over the counter medication for pain relief.”

Approximately one in five pregnancies end in miscarriage, with the highest risk in the first few weeks when many women may be unaware that they are expecting.