Everyone should be aware that that drinking and driving is illegal. However, fewer people realise that some prescription and over-the-counter medications can also make it unsafe (and in some cases, unlawful) to drive.
If you take regular medications, understanding how they might affect your driving is important, not just for safety, but for your legal obligations as a licence holder in NSW.
Your legal obligations in NSW
In NSW, it's an offence to drive while impaired by any substance, including prescription and over-the-counter medications. The key word is "impaired." Taking a medication isn't automatically a problem. Driving while that medication is affecting your ability to drive safely is.
Your prescribing doctor or pharmacist should discuss driving-related side effects with you when starting a new medication or adjusting a dose.
If you have a medical condition that could affect your ability to drive safely, you are legally required to report it to Transport for NSW. Your doctor can advise whether your condition needs to be reported and how it can be managed.
Common medication types that can affect driving
The following categories of medications are known to have potential effects on driving ability. This is not an exhaustive list, and individual responses vary. If you're unsure whether a specific medication affects your driving, speak with your doctor or pharmacist.
Medications that may cause drowsiness or sedation
Benzodiazepines (commonly prescribed for anxiety, insomnia, and muscle spasm) can significantly impair reaction time, attention, and coordination. The effects can persist well beyond when you feel "awake," particularly with longer-acting formulations.
Opioid pain medications can cause drowsiness, slowed reaction time, and impaired concentration. These effects are often most pronounced when first starting the medication or increasing the dose.
Antihistamines can cause significant drowsiness.
Some antidepressants can cause drowsiness, particularly when first starting or when doses are adjusted.
Sleep medications are designed to cause drowsiness, and their effects can persist into the following morning.
Medications that may affect cognition or coordination
Anti-epileptic medications can affect processing speed, attention, and coordination. These effects are usually most noticeable when starting treatment or adjusting doses, and often settle with time.
Some Parkinson's disease medications can cause sudden onset of sleepiness ("sleep attacks"), involuntary movements (dyskinesias), or fluctuations in function between "on" and "off" periods. All of these can affect driving.
Some blood pressure medications can cause dizziness or lightheadedness, particularly when standing or changing position quickly.
Muscle relaxants can cause drowsiness and reduced coordination.
Medications that may affect vision
Medications that dilate the pupils (such as eye drops used for examinations) can temporarily impair vision, particularly in bright conditions. Your pharmacist, doctor or optometrist/ophthalmologist will usually advise you not to drive after these are administered.
Some medications list blurred vision as a side effect. If you notice vision changes after starting a new medication, speak with your doctor before driving.
"Can I drive on this medication?"
This is one of the most common questions people have, and the honest answer is: it depends.
The same medication can affect two people very differently. Factors that influence how a medication affects you include:
The dose
How long you've been taking it (side effects often settle over time)
Whether you're taking other medications at the same time
Your age (older adults are generally more sensitive to medication side effects)
Your individual metabolism
Whether you've recently started the medication or had a dose change
Because of this variability, there's no simple list of "medications you can't drive on." Instead, the general principle is: if a medication is affecting your alertness, reaction time, coordination, vision, or judgement, you should not drive while those effects are present.
Your doctor or pharmacist is the best person to advise on whether a specific medication is likely to affect your driving.
When your doctor or pharmacist should warn you
Your doctor should discuss driving implications when:
Prescribing a new medication that may affect driving
Increasing the dose of an existing medication
Combining medications that may have additive effects (for example, an opioid plus a benzodiazepine)
Your pharmacist should flag driving-relevant side effects when dispensing. Many medications have a warning sticker on the packaging ("may cause drowsiness") or a CMI (Consumer Medicine Information) leaflet that mentions driving.
If neither your doctor nor your pharmacist has mentioned driving, and you're concerned about a medication you're taking, ask. It's a reasonable and important question.
When an OT driving assessment may be needed
In most cases, medication-related driving decisions are managed between you and your prescribing doctor. An OT driving assessment isn't usually needed for straightforward medication questions.
However, an OT driving assessment may be relevant when:
You're on a medication regime that is complex (multiple medications with potential driving effects) and it's unclear how the combined effects impact your actual driving (and this is expected to be a long term regime)
Your medication is for a condition that itself affects driving (for example, Parkinson's disease, epilepsy, or dementia), and the interaction between the condition and the medication needs a practical assessment
You or your family have noticed driving changes since starting or changing medication, and the GP wants an independent evaluation
Transport for NSW has required an assessment based on your medical condition, and medication effects are part of that picture
In these situations, the OT assesses the combined impact of your condition and medications on your on-road driving, which gives a much clearer picture than clinical assessment alone.
Practical tips
Read the Consumer Medicine Information (CMI) that comes with your medication. Look for sections on "driving and using machines" or "things to be careful of."
Be cautious when starting a new medication. Side effects are often worst in the first few days to weeks. Consider avoiding driving during this settling-in period, or at least being extra cautious.
Be cautious after dose changes. An increase in dose can bring back side effects that had settled.
Don't combine medication with alcohol. Many medications have amplified effects when combined with alcohol, even in small amounts.
Do not stop taking your medicines or alter the dose without medical advice. This can also put you at risk when driving.
Tell your OT about all your medications. If you're attending an OT driving assessment, bring a current medication list (or the medications themselves). The OT will factor medication effects into their assessment.
Don't stop medications to "pass" an assessment. If you're attending a GP review or OT driving assessment, take your medications as normal.
Cannabis and driving in NSW
Medicinal cannabis is increasingly prescribed in Australia for various conditions. In NSW, it is currently illegal to drive with any detectable level of THC in your system, even if you have a valid prescription. This is different from other prescription medications, where the question is whether you're impaired, not whether the substance is detectable.
If you're prescribed medicinal cannabis and you hold a driver's licence, discuss the driving implications with your prescribing doctor. The legal situation is evolving, but as of now, driving with THC in your system is an offence in NSW regardless of prescription status.
Getting help
If you're unsure whether your medication is affecting your driving, talk to your doctor or pharmacist. If your GP has concerns and refers you for an OT driving assessment, you can start the process at steerdriving.com.au/referral.
Need an OT driving assessment in Sydney? Steer Driving is a mobile OT driving assessment service covering greater Sydney. If you have a referral from your GP or specialist, you can start the process below.
This article was written by Elise, an AHPRA-registered Occupational Therapist and Transport for NSW-registered driver assessor. Elise is the founder of Steer Driving, a mobile OT driving assessment practice in Sydney.
FAQ Section
Can I drive on prescription medication in NSW? Yes, in most cases. Taking a prescription medication doesn't automatically prevent you from driving. However, if the medication impairs your alertness, reaction time, coordination, or judgement, you should not drive while those effects are present.
Which medications affect driving? Common categories include benzodiazepines, opioid pain medications, some antihistamines, some antidepressants, sleep medications, anti-epileptic drugs, and some Parkinson's disease medications. Individual responses vary, so speak with your doctor or pharmacist about whether your specific medication may affect driving
Can I drive on medicinal cannabis in NSW? Currently, it is illegal to drive with any detectable level of THC in your system in NSW, even with a valid prescription. Discuss the driving implications with your prescribing doctor.
Should I stop my medication before an OT driving assessment? No. Take your medications as normal. The assessment is designed to evaluate your driving under your usual conditions, not an artificial version.
Do I need to report my medication to Transport for NSW? You need to report any medical condition that may affect driving. If medication side effects are significantly impacting your driving ability, this may fall under that obligation. Your GP can advise.
When should I talk to my doctor about driving and medication? Whenever you start a new medication, have a dose change, or notice side effects that could affect driving (drowsiness, dizziness, blurred vision, slower reactions). Ask your doctor or pharmacist if you're unsure.