People who use prescription medication will be reminded to ensure it does not impair their ability to drive, as a move to crack down on drug-driving is considered by MSPs.

The proposals would see legislation introduced that would make it an offence to drive while above specified drug limits.

Existing law makes it an offence to be in charge of a motor vehicle while unfit to drive through drink or drugs, although the penalties (minimum 12-month driving ban, up to six months in prison and a fine of up to £5,000) are reserved to Westminster.

The new offence would operate alongside the current offence and carry with it the same maximum penalties.

It would also place a zero-tolerance limit on eight drugs most associated with illegal use, including cannabis, heroin and cocaine

There are currently no prescribed limits for controlled drugs, although the ability to provide specified limits for drugs is devolved.

Several drugs with medical uses will have limits based on impairment. The list includes; clonazepam, diazepam, flunitrazepam, lorazepam, methadone, morphine, oxazepam and temazepam.

A separate approach will be taken to amphetamine, balancing its legitimate use for medical purposes against its abuse.

Any person taking medication in line with their prescription can claim the medical defence to the new offence.

However, they can still be prosecuted under the existing impairment offence if the prescription indicates that they should not drive while taking the medication – meaning they are unable to claim the medical defence.

Speaking at a Holyrood committee on Thursday, Community Safety minister Ash Denham, said that an information campaign would be launched to ensure that those in the medical profession advise individuals over whether their medication could impact on their ability to drive.

Ms Denham said: “There is a role here for medical professionals and pharmacists in terms of making sure that people have the correct information.

“Obviously those that are on prescription medications would be able to rely on the medical defence as long as they comply with the instructions given to them by their medical professional.

“We will be making sure that they have bespoke information and advice that’s made available to all medical practitioners, and that would include pharmacists, regarding this change in the law and also the operation of medical defence”.

Labour MSP Daniel Johnson indicated to the committee that he takes a controlled drug, methylphenidate, on a prescribed basis, as a result of his ADHD diagnosis.

Mr Johnson asked Ms Denham if it would be the case that people would have to be fully aware of the small print that comes with medication.

The Labour MSP said: “You correctly say that the medical advice should be clear to them, but how are you going to make sure that people are aware whether or not they are safe to drive?

“I think there’s also the flipside of that with people being worried that they may be in breach of the law when they don’t need to worry because either the drug that they take isn’t within this list or they’re well within the safe limits based on medical advice”.

Ms Denham said: “That comes within the wider awareness raising campaign, but updated guidance to medical professionals and pharmacists to make sure that they are advising their patients correctly.

“But it is also people’s duty to make sure that if they are consuming medicines that they are not impaired and if they feel that they are impaired, then they shouldn’t be driving.

“But if you’re taking the medication at appropriate dosage and in line with  your medical practicioner’s advice, then you should be in accordance with the law at that point”.

Mr Johnson responded: “Is there going to be specific instructions to pharmacists and GPs to provide communication and what form will that take? Will it be in writing? Or will it simply be when they next pick up their prescription?

“Because we’re talking about a population of people who may well have been taking medication for quite a prolonged period of time and it’s very normalised for them and they may not simply think to ask the question”.

Ms Denham said: “We will be updating the advice for doctors and for pharmacists as well and they’ll be advising their patients accordingly”.

Philip Lamont, Criminal Justice Division, said: “I think there will be a need for medical professionals to make sure that any previous guidance that they should have offered about whether to drive or not, that there’s a reminder given to patients”.