U.S. Food and Drug Administration staff have expressed concerns over likely errors in administering Purdue Pharma's fast-acting oxycodone painkiller that could result in inadequate relief.

The drug is designed to be taken every 4-6 hours on an empty stomach as the absorption of oxycodone from the drug can be substantially delayed in the presence of food, studies have shown.

This "food effect" may reduce the effectiveness and safety of the drug, to be called Avridi, FDA reviewers have said. (1.usa.gov/1NfxZxd)

To prevent such errors, privately held Purdue proposed to make clear on the label that the opioid painkiller is to be taken on an empty stomach.

However, the reviewers said on Tuesday that this would be insufficient as opioid painkillers are typically taken without regard to food intake and administering the drug could interfere with meal timings.

Inadequate pain control caused by presence of food could lead to overdosing, the reviewers said.

Abuse of opioid drugs can produce euphoric highs and even disrupt the parts of the brain that control breathing.

A panel of outside advisers is scheduled to meet on Thursday to recommend whether the drug should be approved. The FDA is not obliged to follow the advice of its advisory panels but usually does.

Stamford, Connecticut-based Purdue Pharma, founded by doctors, has a plethora of pain relief products on the market.

The company said on Tuesday it had acquired an experimental chronic pain drug for up to $213 million.

FDA staff are also expected to post a review on Wednesday of a longer-acting version of oxycodone, developed by Collegium Pharmaceuticals Inc. Unlike Avridi, this drug must be taken with food, studies show.