As a health professional, you can help your patients be informed about how their medication – and other substances they may be taking such as illegal drugs and alcohol – can affect their driving. You can help them make good choices about whether or not they’re safe to drive.

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What is substance impaired driving?

Substance impaired driving is when a person’s ability to drive is affected because they have taken a drug or medication, a combination of these or combined them with alcohol.

It’s illegal to drive when impaired, whatever the cause of the impairment (symptoms, illness, injury) and police will enforce this law.

Five types of medications most often prescribed by New Zealand doctors make up three-quarters of those that may impair driving:

  • analgesics
  • antidepressants
  • heart medications (beta blockers/calcium channel blockers)
  • antihistamines
  • sedatives.

Five less common prescription medications make up most of the rest:

  • antipsychotics
  • anti-epilepsy drugs
  • substance dependence treatments
  • anti-nausea medications
  • anxiolytics.

These 10 medications account for over 95 percent of prescription medications that may impair driving in New Zealand.

Talk to your patient about how their driving could be affected if they’re:

  • taking one or more of these medications
  • taking some of the variants sold as ‘pharmacy only’
  • taking over-the-counter’ medications such as antihistamines or cold and flu preparations.

Some signs or symptoms of medication impaired driving

  • feeling drowsy or sleepy
  • blurred vision
  • headache
  • feeling weak
  • slowed reactions
  • dizziness
  • nausea, feeling sick
  • unable to focus or pay attention
  • being easily confused
  • slurred speech
  • having trouble forming a sentence
  • feeling wired and overconfident (although a person may not notice this themselves).

Have the ‘safe to drive’ conversation with your patients

  • Let your patients know if their medication could affect their driving.
  • Make sure they check for symptoms each time they drive.
  • Advise how long the effects of their medication may last.
  • Tell them whether they should avoid alcohol while taking their medication as it may multiply the risk.
  • Advise them not to stop taking their medication so they can drive.
  • Talk about the options, such as trying a different medication or dose, or taking their medication at a different time.
  • Advise them of what they need to tell their employer.

You might also want to raise one of these:

  • The decision to drive is their responsibility.
  • Reactions times are really slowed when they’re impaired.
  • ‘Impairment’ may only be temporary.
  • Other drugs like cannabis or over-the-counter medications may affect their driving.
  • Car insurance may be affected if they drive impaired when they’ve been told not to drive on strong medications.
  • Discuss alternatives to driving such as taking the bus or getting a lift. Talk about how long they may have to do this.
  • Consider the effects when they change their routine –such as evening activity or a very early start.
  • Make a plan for emergency night-time driving.

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