US medical regulators now warn that heart attacks and strokes can occur in the first few weeks of taking some pain relievers.

US federal health regulators are bolstering warning labels for popular pain relievers, adding information about the risk of heart attack and stroke in the short term.

The changes announced Thursday apply to prescription non-steroidal anti-inflammatory drugs, or NSAIDs, including arthritis treatments like Celebrex.

The agency said it plans similar changes to over-the-counter drugs in the same class, such as Advil and Motrin.

Language on the pills currently warns that they can increase the risk of heart-related problems if used long term.

But the Food and Drug Administration's new warning states that heart attacks and strokes can occur in the first few weeks of taking the drugs.

The agency also warns that the risks increase with higher doses of the drugs. The updates are based on an FDA review of recent studies and recommendations by outside advisers.

"In general, patients with heart disease or risk factors for it have a greater likelihood of heart attack or stroke," the agency notes in the announcement posted to its website.
The labelling change is the latest step in the FDA's ongoing safety review of the drugs, which stretches back to 2004.