An increasing number of blood and urine samples from drivers suspected of driving while intoxicated are being analysed for drugs other than alcohol, according to the latest figures from the Medical Bureau of Road Safety.
Last year 109 samples were analysed for drugs, representing a 100 per cent increase on the figures for 1999. The equivalent alcohol analysis figures are in excess of 10,000 per annum.
A detailed breakdown of the drug analysis figures for 2000 shows that both cannabis and amphetamines are the principal drugs misused by drivers.
Benzodiazepines - which may have been prescribed for legitimate medical reasons - accounted for 20 per cent of the positive tests. Methadone, which is commonly prescribed to help recovering heroin addicts, was found in 8 per cent of samples, slightly more than for heroin and other opiate drugs.
Cocaine was found in only 1 per cent of urine and blood tests, in contrast to figures from North America where the drug is the most common found by the authorities in drivers suspected of drug-driving.
Prof Denis Cusack, director of the Medical Bureau of Road Safety at University College Dublin, told The Irish Times that since January 1st all samples taken from drivers had been automatically tested for drugs if they were found to be negative for excess alcohol.
He confirmed that plans were being drawn up to analyse all samples for the presence of the top three drugs, regardless of whether they were positive for alcohol or not. This expanded analysis is likely to be introduced in 2003.
The data from 2000 indicate frequent use of more than one drug by intoxicated drivers; 66 per cent of confirmed specimens contained two or more drugs, while 10 per cent had four or more drugs present.
Nine drivers tested positive for both alcohol and drugs.
All the drugs tested for by the Medical Bureau of Road Safety have the capacity to impair driving. While most will produce sedation and inattention, drugs such as amphetamines can cause a state of hyper-alertness, in which the brain is over-aware of stimuli, resulting in dangerous driving.
Prof Cusack said: "The biggest overall problem is still alcohol, but we have a significant drug-driving problem also".