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In Ireland you can drive while taking prescribed medicines, including medicinal cannabis, as long as you are not impaired. Cannabis is one of three drugs (with cocaine and heroin) where driving over a legal threshold is an offence even without proof of impairment. A driver lawfully prescribed a medicinal cannabinoid can hold a medical exemption certificate signed by their doctor, which covers that threshold offence. It never covers impaired driving. The guidelines say to carry the certificate at all times when driving.
This page explains the law, not treatment. Ask your doctor or pharmacist how your own medicines affect you.
How drug driving law works in Ireland
- Roadside testing: Gardaí can test oral fluid at the roadside or in a station for cannabis, cocaine, opiates, benzodiazepines and amphetamines (including methamphetamine). This can happen at a Mandatory Intoxicant Testing checkpoint.
- Threshold offence: for cannabis, cocaine and heroin, driving over the legal threshold is an offence and Gardaí do not need to prove impairment.
- Impairment offence: for any drug, including prescription medicines, it is an offence to drive while impaired. A positive roadside test or a Garda’s opinion that you are impaired can lead to a blood or urine specimen being analysed by the Medical Bureau of Road Safety.
- Penalties: conviction for drug driving means disqualification. The judge decides the length, and minimum periods are set in law.
- Refusal: refusing a preliminary oral fluid test is itself an offence.
How a roadside drug test and impairment test work in practice is covered in Tiredness, drugs and road rage.
The medical exemption certificate
| Question | Answer |
|---|---|
| What is it? | The Medical Exemption Certificate under the Road Traffic Act 2010, in the form set by S.I. No. 158 of 2017 |
| Who signs it? | Your prescribing doctor |
| What does it cover? | A medicinal cannabinoid product containing THC lawfully prescribed to you. It covers the cannabis (THC) threshold offence |
| Does it let you drive impaired? | No. Gardaí state that the certificate does not allow you to drive if you are impaired |
| Where do you get the form? | The NDLS website |
| Do you need to carry it? | The medical fitness guidelines say drivers should carry it at all times when driving |
The certificate is for prescribed cannabinoids. For other medicines, such as opioid painkillers or benzodiazepines, the legal question is whether they impair your driving.
Sativex and other medicinal cannabis
The guidelines note that Sativex, which contains THC and CBD, was authorised in 2014 for adults with moderate to severe spasticity due to multiple sclerosis who have not responded to other treatment. Medicinal cannabis may impair judgment and skilled tasks, though drivers adapted to a stable dose generally, but not always, keep their driving ability. You should watch for any impairment especially when starting treatment and until you are on a stable daily dose. For other prescribed cannabis products, including those supplied through the Medical Cannabis Access Programme, ask your prescriber whether a certificate applies to you.
Other prescribed medicines
Sláinte agus Tiomáint gives this general guidance:
- Most medicines, except benzodiazepines, do not significantly raise crash risk when taken as prescribed and once you are stable on them.
- Benzodiazepines, especially long-acting ones, increase crash risk.
- Opioid painkillers: thinking can be slowed early in treatment, but drivers on a stable dose may not have a higher crash risk. Night driving may be harder because opioids narrow the pupils.
- Sedating antidepressants and antipsychotics can impair driving, especially when starting or increasing the dose.
- Combining medicines, or medicines with alcohol, adds to the risk.
Gardaí advise following your doctor’s and pharmacist’s advice and reading the patient information leaflet, which says whether the medicine can affect driving.
What this means for learner and novice drivers
- The drug driving offences and the exemption certificate apply to learner permit holders exactly as to full licence holders.
- Do not drive, even with your accompanying driver, when starting or changing a medicine until you know how it affects you.
- If you take medicinal cannabis, get the certificate signed before you start lessons and keep it with your learner permit.
- A drug driving disqualification as a learner can delay your full licence, so ask your doctor before you drive.
Related: ADHD, autism and mental health: Irish licence rules and Epilepsy and driving in Ireland. Back to the hub: Driving with a medical condition or disability in Ireland.
Sources
- An Garda Síochána and Medical Bureau of Road Safety, “Updated FAQ Document on Drug Driving and Testing”, 1 December 2022 (garda.ie)
- Government of Ireland, “S.I. No. 158/2017: Road Traffic Act 2010 (Medical Exemption Certificate) Regulations 2017” (irishstatutebook.ie)
- Government of Ireland, Road Traffic Act 2016, section 8 (irishstatutebook.ie)
- Road Safety Authority and National Office for Traffic Medicine, “Sláinte agus Tiomáint: Medical Fitness to Drive Guidelines”, 13th edition, April 2026, prescription medicines and driving section (rsa.ie)