Common medications might affect older people’s driving: Study

Researchers from the United States have found that some commonly used medications, including paracetamol and non-steroidal anti-inflammatories, may negatively impact the driving ability of older people.
 
The study, published in JAMA Network Open, included almost 200 active drivers aged 65 years or older who were cognitively healthy and living in the community, with driving playing a pivotal role in their independence.
 
‘The ability to drive independently supports community mobility, social connectedness, and critical access to healthcare,’ the authors wrote.  
 
In Australia, one in six people are aged 65 or older – which equates to 4.2 million adults, most of whom are active drivers.
 
Participants involved in the US-based study were followed prospectively on an annual basis over a 10-year period, with data collection finalised in early 2023.
 
Participants had an average age of 72 years, with 35% of the cohort either failing a practical driving assessment or receiving a borderline result during the study period, reflective of poor driving ability.
 
By analysing the medication used by the drivers, the researchers determined what medications were associated with a higher risk of performing poorly on the driving test.
 
Paracetamol, non-steroidal anti-inflammatories, anti-depressants, sedatives and hypnotics were all associated with poorer performance on the driving assessment.
 
Conversely, the researchers found that those taking lipid-lowering medications were less likely to fail the driving test. Antihistamines and anticholinergic medications were found to have no impact on driving performance.
 
The authors postulate that the reason for these findings is the mechanism of action of psychoactive drugs, but the role of simple analgesia is less clear. It is hypothesised that lipid-lowering therapy may have benefited drivers by optimising brain health.
 
‘The negative association between psychoactive drug use and driving performance may be explained by the effect of these drugs on neurotransmitters, such as noradrenaline, serotonin, histamine, acetylcholine, and GABA,’ the authors wrote.
 
‘Numerous studies have suggested the protective effects of statin on cognitive functioning, which could have a positive impact on driving.’
 
As an observational study, the findings are unable to determine a causal relationship between medication use and driving performance; however, the researchers suggest that doctors should be mindful of the results.
 
‘While we cannot determine whether these medications directly caused the risk of decline in driving performance individually or collectively, our results raise concern about the potential negative impact of potentially driver-impairing medications on driving performance,’ they wrote.
 
‘Clinicians and pharmacists should be aware that patients who are prescribed these drugs could be at an increased risk of driving impairment. A clear discussion and review of medications in relation to the driving task should be included in the care of older adults.’
 
An Rendell, who manages the Assessing Fitness to Drive implementation project at Austroads, told newsGP that GPs should refer to the current standards for fitness to drive when considering medication use.
 
According to the standards, most drugs that have effects on the central nervous system ‘tend not to pose a significantly increased crash risk when the drugs are used as prescribed and once the patient is stabilised on the treatment’.
 
The exception being benzodiazepines, which have an established increased risk of motor vehicle accident and are found in approximately 4% of fatalities and 16% of injured drivers who are seen in hospitals.
 
When assessing patients on their fitness to drive and offering advice regarding medication use, health professionals should consider the following:

• the balance between potential impairment due to the drug and the patient’s improvement in health on safe driving ability
• the individual response of the patient – some people are more affected than others
• the type of licence held and the nature of the driving task
• the added risks of combining two or more drugs capable of causing impairment, including alcohol
• the added risks of sleep deprivation on fatigue while driving, which is particularly relevant to commercial vehicle drivers
• the potential impact of changing medications or changing dosage
• the cumulative effects of medications
• the presence of other medical conditions that may combine to adversely affect driving ability
• other factors that may exacerbate risks such as known history of alcohol or drug misuse.

aged care fitness to drive research