Frank Sheahan has been forced out of the Ireland tour party currently in Australia after testing positive for drugs.
However, the 26-year-old hooker insisted he was guilty of nothing more than an administrative error after failing to declare he suffered from asthma.
Sheahan produced a positive urine test for banned substance Salbutamol, which is contained in inhalers for asthma, after playing for Munster in the European Cup semi-final defeat away to Toulouse on April 26th.
Under both European Rugby Cup (ERC) and Irish Rugby Football Union (IRFU) regulations, Sheahan was temporarily suspended from all playing activity until such time as the ERC anti-doping procedures are concluded and his case heard before the ERC's independent judicial tribunal.
"I am shocked to learn of this development but I am absolutely satisfied it results from an administrative error," said Sheahan in an IRFU statement.
He added: "Apparently, I did not tick off the appropriate box to show I have a medical need to use Ventolin, which contains Salbutamol, because of asthma, which all my medical records show.
"Ventolin is not a forbidden substance and it is simply a technicality of having it declared on the form.
"While I am devastated at having to leave the tour, I am now anxious to get home and meet my medical advisers in order to put together the documentation that will clarify what I am happy is effectively a human error in administration."
Sheahan has been capped 13 times by Ireland but has spent most of his international career on the bench, first as back-up to Keith Wood and, following the former captain's injury problems, Shane Byrne.
Ireland play world champions Australia in Perth on June 7th, Tonga on June 14th and Samoa on June 20th as part of their preparations for this October's World Cup.