Pharmac supplied asthma drug contains ethanol

Using asthma inhalers may give false positive results in roadside alcohol breath tests, a report in the New Zealand Medical Journal suggests.

Whangarei medical practitioner and researcher Shane Reti said in early April 2005 a 62-year-old non-alcohol-drinking woman was assessed by a police roadside breath testing unit.

After speaking into a testing device she was told she had failed. A few minutes before being tested she had taken one puff of her Salamol asthma inhaler.

The woman explained the situation to police and was allowed to proceed on her journey. But she later contacted her GP, concerned she had failed a breath test.

With the assistance of Northland police district road policing manager Inspector Rob Lindsay, Dr Reti undertook testing at the Whangarei police station.

The first stage of roadside breath testing involves speaking into an Alotech device. Dr Reti passed initially, but after taking two puffs of Salamol recorded a "fail", meaning alcohol was detected. At one and two minutes later he also failed, but passed at three minutes.

To test the second stage of breath testing, Dr Reti blew into the Alotech device through a mouthpiece. The result was a "pass" even after taking puffs from the inhaler.

The third stage of breath testing involves blowing twice into an Ethylometer, 2 1/2 minutes apart. In New Zealand a driver fails if more than 400 micrograms of alcohol per litre of breath is detected.

It is these readings that are used as evidence in court when drivers are prosecuted for drink driving.

The article said anecdotal reports suggest testing with a mouth rinsed in wine records approximately 40 micrograms per litre.

After two puffs of Salamol, Dr Reti's results over three trials on the first blow were 1201, 1283 and 1861 micrograms per litre. The results on each second blow were all zero.

Dr Reti said further testing would be required to confirm the significance of the findings but the preliminary results showed some failing of certain aspects of roadside breath testing.

He said overseas recommendations for retesting after someone uses an inhaler range from two to 20 minutes.

In early 2005 Pharmac advised that Salamol would replace Ventolin as a subsidised metered-dose asthma inhaler. Both have salbutamol as their active ingredient, but Salamol also contains ethanol, an alcohol.

In response yesterday Pharmac medical director Dr Peter Moodie said: "What this paper shows is that no one is at any risk of prosecution as a result of using Salamol asthma inhalers.

"People who use this inhaler will be putting small amounts of alcohol into their mouth, but this is evaporated in about 1-2 minutes."

- NZPA