Drivers who take prescription drugs are being warned ahead of new drug-driving laws coming into force next month.
People who have been prescribed powerful anxiety or pain relief drugs such as clonazepam, diazepam or lorazepam are affected by the laws which come into effect on March 2, 2015.
The new law aims to catch those who put the lives of others at risk while driving under the influence of drugs.
As well as outlawing driving while under the influence of illegal drugs, such as cannabis, new legislation will include some prescription medicines.
But prescribed doses do not exceed the limits for legal drugs, so most patients should still be safe to drive.
Those who are unsure are advised to seek the advice of a pharmacist.
The new law sets very low levels for eight well known illegal drugs, including cannabis and cocaine, but also includes eight prescription drugs: clonazepam, diazepam, flunitrazepam, lorazepam, oxazepam, temazepam, methadone and morphine.
Most of them, including temazepan and diazepam, are used for treating conditions such as anxiety. But the list also includes methadone, a heroin substitute, and morphine, a powerful opiate used for pain relief.
Robert Goodwill MP, Road Safety Minister, says as long as they stay within prescribed levels, most people will still be able to get behind the wheel of a car.
"If you are taking your medicine as directed and your driving is not impaired, then you are not breaking the law and there is no need to worry," he said.
"We advise anyone who is unsure about the effects of their medication or how the new legislation may affect them, to seek the advice of their doctor or pharmacist.
"There will also be a medical defence if a driver has been taking medication as directed and is found to be over the limit but not impaired.
"Drivers who are taking prescribed medication at high doses [are advised] to carry evidence with them, such as prescriptions slips, when driving in order to minimise any inconvenience should they be asked to take a test by the police."
