Scientists fear the drugs may cause blood vessels to narrow, increase fluid retention and alter blood pressure
They include popular over-the-counter pills such as ibuprofen, and prescription-only drugs such as diclofenac.
Both are taken by millions for conditions such as headaches, back pain and arthritis.
The study, published in The BMJ, said their effect on heart attack risk was almost immediate.
But it was not long-lasting and wore off over time.
Past studies have found the common painkillers increase risk of cardiac arrest by up to a third.
Scientists fear the drugs may cause blood vessels to narrow, increase fluid retention and alter blood pressure.
Canadian experts found taking any regular dose of ibuprofen for between one to seven days raised chances by 48 per cent.
For diclofenac it went up 50 per cent, and naproxen 53 per cent.
Taking stronger pills was more dangerous, but using the painkillers for longer than a month did not greatly alter risk.
Lead researcher Michèle Bally, from the University of Montreal Hospital Research Center, said: “This study reveals a new finding, which is that for all common NSAIDs the risk of heart attack starts as early as in the first one to seven days of use.
“We found any dose could increase risk between 20 to 50 per cent, so people should consider alternatives when treating aches and pains.
“Can they get physio or try paracetamol instead?
“Our study supports recommendations to use the lowest effective NSAID dose for the shortest possible time.”
Scientists fear the painkillers may cause blood vessels to narrow, increase fluid retention and alter blood pressure
Around 190,000 Brits are rushed to A&E with a heart attack each year.
Dr Mike Knapton, from the British Heart Foundation, said: “This large-scale study worryingly highlights just how quickly you become at risk of having a heart attack after starting NSAIDS.
“Whether you are being prescribed painkillers like ibuprofen, or buying them over the counter, people must be made aware of the risk and alternative medication should be considered where appropriate.”
OFFER PATIENTS ALTERNATIVE THERAPIES, TOP DOC WARNS
MEDICS last year doled out 13.8 million prescriptions for NSAIDs, according to NHS Digital.
Britain’s top family doctor Professor Helen Stokes-Lampard said the public need to be made aware of the risks.
And said doctors should offer patients alternative therapies where possible.
Prof Stokes-Lampard, chair of the Royal College of GPs, said: “Chronic pain can cause considerable distress for our patients.
“This study builds on research highlighting the risks involved in using NSAIDs, such as ibuprofen. It should also raise awareness amongst patients who self-medicate with NSAIDs available over the counter.
“Their use in general practice to treat patients with chronic pain is reducing, as we know long term use can lead to serious side effects for some patients.
“But these drugs can be effective in providing short term pain relief.
“We know that what works best for treating many cases of chronic pain is a combination of therapies, be these physical, psychological or pharmacological.”
Dr Amitava Banerjee, Honorary Consultant Cardiologist at UCL, said: “The increased risk of heart attack with NSAIDs means that both health professionals and the public should weigh up the harm and the benefit when prescribing these medications, especially for more than a day or two.”
But John Smith, chief executive of the Proprietary Association of Great Britain, the UK trade association representing manufacturers of branded over-the-counter medicines, said the public should not be alarmed.
He said the study focused on high-dosages that can only be prescribed by doctors.
He said: “People taking over-the-counter NSAIDs should not be concerned by this research if they are taking the medicine occasionally for short periods and according to the on-pack instructions.”
Last September, a piece of research warned ibuprofen could increase the risk of heart failure by 20 per cent.
Meanwhile, another team of scientists found taking the painkiller to ease flu symptoms, increases heart attack risk.