A Queensland coroner has recommended a warning label be placed on the quit-smoking drug Champix.

The call comes after the Queensland coroner reopened an inquest into the death by suicide of 22-year-old Timothy John in April 2013.

Mr John had been on Champix for eight days when he died, leaving a suicide tape for his mother next to a box of the quit-smoking drug.

After his mother gathered 49,000 signatures on an online petition, the coroner reopened the inquest into the circumstances of his death.

“I find that Champix contributed to Timothy's death,” coroner John Hutton said.

He found that Mr John’s doctor, Oliver Yang, “did not provide adequate care” when prescribing the man Champix.

“If Timothy's family had been informed by Dr Yang (or by warnings within the Champix packaging) about the need for Timothy to stop taking Champix and to contact a doctor immediately if he exhibited neuropsychiatric symptoms, it is likely that his family would have taken appropriate earlier action, and it is possible that Timothy's death may have been avoided,” Mr Hutton said.

In the US, the drug carries a ‘black box’ warning about its side effects.

In 2009, drug-maker Pfizer settled a class action about the side effects of Champix (known in America as “Chantix”), as part of a settlement with thousands of users said to be worth about $US300 million.

In Australia, any link between Champix and suicide has been slower to prove.

The Therapeutic Goods Administration (TGA) says warnings about the drug are available on Pfizer's website and other places online.

“I find that certain aspects of the product labelling and instructions provided with Champix are inadequate and some improvements may be made,” Mr Hutton said in his findings.

He recommended that Pfizer, in consultation with the TGA, make improvements to Champix labelling, its information leaflet and product information document.

Mr Hutton also recommended all state and territory forensic pathology services undertake “routine toxicology screening for [Champix] in relation to suicides and suspected suicides”.

The coroner did not make an official reading of the level of contribution the drug had on Mr John’s death.