Travelling can be stressful at the best of times for those on medication, not least when taking a flight. Many suffer from a fear of flying, or simply struggle with the logistics of getting through the airport to their destination.

Now, a doctor has warned airline passengers of the dangers of taking some notable medications while flying. Dr Sean Ormond from Atlas Pain Specialists is a qualified medical professional based in Phoenix, Arizona in the US.

He is dual board-certified in both anaesthesiology and interventional pain management, so is well-placed to offer advice to travellers. Dr Ormond has compiled a list of seven medications which should be avoided while on the plane and the reasons why.

He said: “As a pain management doctor, I always emphasise the importance of being mindful of medications, especially while flying. Air travel can impact how drugs work in your body, and some meds can cause serious issues at high altitudes.”

The doctor also gave a caution to travellers.

He said: “Before you fly, check in with your doctor about any meds you’re taking, especially if you have chronic pain or other conditions. Staying hydrated, stretching, and using non-medicated comfort measures can make a world of difference.”

Here’s the full list of medications Dr Ormond recommends avoiding while in the air:

7. Blood thinners – use with care

It is wise to be particularly mindful on long-haul flights if you are on blood thinners, as these big flights involve sitting down for hours at a time. Staying sat increases the risk of blood clots and even minor injuries could cause a high level of bleeding. Dr Ormond’s advice is to stand up and move every hour, as well as wearing compression socks and talking to your doctor about precautions before flying.

6. Strong muscle relaxers

This medication can make users feel wobbly or weak, which is not great for staying active on longer flights. Staying seated is not great on planes, and we know already the dangers of blood clots, so Dr Ormond recommends stretching gently and considering “air-activated heat patches” as an alternative.

5. Drowsy antihistamines

As their name suggests, these pills can be good for sending users to sleep, but this is less than ideal when travelling in the air. They can make users groggy, slow reaction times and indirectly increase the risk of blood clots by keeping you sat for longer than you might otherwise be. If allergies or motion sickness are problematic, Dr Ormond’s advice is to consider non-drowsy options such as Claritin or Allegra.

4. Diuretics

This type of medication is often used to aid swelling and blood pressure, but they do have the side effect of encouraging a more frequent need to pee. Air travel is known for being a dehydrating activity, so there is a risk that diuretics can leave users dizzy, weak and lightheaded. Dr Ormond says users of this medication should consider whether they must take them and if so, drink lots of water and consider booking an aisle seat for easy bathroom access.

3. Anti-anxiety medication

Flying can be a nerve-racking activity and fear of air travel is not uncommon, leading many to consider medical options to relieve their symptoms. Yet this medication can have a more pronounced effect at high altitudes, leading to users feeling sluggish, having trouble breathing or even passing out on the plane. Advice from Dr Ormond includes trying deep breathing, distraction techniques or natural remedies such as melatonin if flying is a stressful activity.

2. Sleeping pills

These are not uncommon for those wanting some guaranteed rest on a flight, but can lead to grogginess, disorientation or even sleepwalking down the aisle. If there were an emergency onboard, it’s important also that passengers are alert and can follow instructions, so Dr Ormond recommends a good eye mask, neck pillow and noise-cancelling headphones instead.

1. Opioid painkillers

The top medication recommended to avoid by Dr Ormond is opioid painkillers, which have the effect of drowsiness on the ground, a symptom which is exaggerated in the air. These pills slow breathing, which is not good in a low-oxygen environment, while they can also cause dizziness, nausea or even confusion. Our expert recommends considering non-opioid options where pain relief is needed, such as ibuprofen or acetaminophen.