Initial toxicology tests on airshame DJ Neil Prendeville have shown he had no illicit drugs in his system.
The shock-jock volunteered for a drugs test after allegations that he performed a sex act on himself during a flight last month.
Doctors have returned the early reports of those examinations which his solicitor says proves the 49-year-old had not taken anything except alcohol.
Solicitor Gerald Kean said that Mr Prendeville is not blaming the painkiller Nurofen for his “total memory loss”.
The manufacturer of the over-the-counter drug had reacted angrily to some reports that it was partly to blame for the Cork 96FM DJ's bizarre behaviour.
“Nobody ever suggested that Nurofen caused memory loss. There is a thing called booze, alcohol,” said Mr Kean.
“He only pointed out that he took Nurofen as he was trying to recall the events of the day.”
Mr Prendeville went on a media offensive at the weekend by giving a series of interviews to Sunday newspapers ahead of a meeting with his bosses in UTV this week.
He admitted to feeling suicidal since allegations emerged last week that he exposed himself and then masturbated on a Heathrow-Cork flight on October 19.
A Garda investigation is now underway following the receipt of formal complaints from Aer Lingus stewardesses. The two passengers seated beside Mr Prendeville have already given statements to gardai.
Mr Prendeville has said that he doesn't remember anything from the time he left a London restaurant until he was back in Cork.
According to Mr Kean his client has had “an horrendous week” but his family, including wife Paula, are standing by him.
The broadcaster – who earns €150,000-plus a year for his morning chat show – has spent the past few days at the Wicklow home of his solicitor in a bid to shield his family from the media spotlight.
But he will meet face-to-face with radio station bosses later this week and is prepared to fully co-operate with gardai.
It is understood that 96FM is carefully monitoring the controversy in a bid to gauge the potential reaction of listeners and advertisers to Mr Prendeville's morning chat show.
“He intends returning to work,” insisted Mr Kean.
In his interviews, Mr Prendeville said that his biggest regret is the effect the controversy is having on his children and wife Paula Lenihan, who is the editorial director of RSVP magazine.
“I know the emotions they must be going through. It must be horrific - and it was all my doing. I brought this upon them,” he said.
He admitted that his wife only found out about the incident 24 hours before a newspaper published the story and was absolutely devastated.