Meldonium users may continue to avoid bans under new Wada guidelines

Meldonium was added to Wada's list of banned substances in January 2016

Athletes who test positive for banned substance meldonium after next month's Olympic Games in Rio may not face sanctions, under new guidelines.

The World Anti-Doping Agency (Wada) has extended the period in which athletes who test positive may not be punished.

Those found to have low levels of meldonium in tests before 30 September can now be cleared.

Studies have shown the drug takes longer to be cleared from the system than previously thought.

Athletes who test positive in the new period will be cleared via a "no-fault finding" if less than one microgram per millilitre is detected.

Meldonium was added to Wada's list of banned substances in January 2016.

A study in March said up to 490 athletes may have taken meldonium at the 2015 European Games in Baku.

The new guidelines do not apply to Russian tennis player Maria Sharapova, who is appealing against a two-year suspension after admitting taking the drug after 1 January.

Meldonium increases blood flow and is typically used to treat heart conditions.