During the pandemic, a lost sense of smell was quickly identified as one of the key symptoms of COVID. Nearly four years later, one in five people in the UK is living with a decreased or distorted sense of smell, and one in twenty have anosmia – the total loss of the ability to perceive any odours at all. Smell training is one of the few treatment options for recovering a lost sense of smell – but can we make it more effective?

Smell training is a therapy that is recommended by experts for recovering a lost sense of smell. It is a simple process that involves sniffing a set of different odours – usually essential oils, or herbs and spices – every day.

The olfactory system has a unique ability to regenerate sensory neurons (nerve cells). So, just like physiotherapy where exercise helps to restore movement and function following an injury, repeated exposure to odours helps to recover the sense of smell following an infection, or other cause of smell loss (for example, traumatic head injury).

Several studies have demonstrated the effectiveness of smell training under laboratory conditions. But recent findings have suggested that the real-world results might be disappointing.

One reason for this is that smell training is a long-term therapy. It can take months before patients detect anything, and some people may not get any benefit at all.

In one study, researchers found that after three months of smell training, participation dropped to 88%, and further declined to 56% after six months. The reason given was that these people did not feel as though they noticed any improvement in their ability to smell.

Cross-modal associations

To remedy this, researchers are now investigating how smell training can be improved. One interesting idea is that information from our other senses, or “cross-modal associations”, can be applied to smell training to promote odour perception and improve the results.

Cross-modal associations are described as the tendency for sensory cues from different sensory systems to be matched. For example, brightness tends to be associated with loudness. Pitch is related to size. Colours are linked to temperature, and softness is matched with round shapes, while spiky shapes feel more rough. In previous studies, these associations have been shown to have a considerable influence on how sensory information is processed. Especially when it comes to olfaction.

Recent research has shown that the sense of smell is influenced by a combination of different sensory inputs – not just odours. Sensory cues such as colour, shape, and pitch are believed to play a role in the ability to correctly identify and name odours, and can influence perceptions of odour pleasantness and intensity.

In one study, participants were asked to complete a test that measured their ability to discriminate between different odours while they were presented with the colour red or yellow, an outline drawing of a strawberry or a lemon, or a combination of these colours and shapes. The results suggested that corresponding odour and colour associations (for example, the colour red and strawberry) were linked to increased olfactory performance compared with odours and colours that were not associated (for example, the colour yellow and strawberry).

While projects focusing on harnessing these cross-modal associations to improve treatments for smell loss are underway, research has already started to deliver some promising results.

In a recent study that aimed to investigate whether the effects of smell training could be improved with the addition of cross-modal associations, participants watched a guidance video containing sounds that matched the odours that they were training with. The results suggest that cross-modal interactions plus smell training improved olfactory function compared to smell training alone.

The results reported in recent studies have been promising and offer new insights into the field of olfactory science. It is hoped that this will soon lead to the development of more effective treatment options for smell recovery.

In the meantime, smell training is one of the best things you can do for a lost sense of smell, so patients are encouraged to stick with it so that they give themselves the best chance at recovery.

Emily Spencer, PhD Candidate, Olfaction, Edinburgh Napier University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Opioids are commonly prescribed when you’re discharged from hospital after surgery to help manage pain at home.

These strong painkillers may have unwanted side effects or harms, such as constipation, drowsiness or the risk of dependence.

However, there are steps you can take to minimise those harms and use opioids more safely as you recover from surgery.

Which types of opioids are most common?

The most commonly prescribed opioids after surgery in Australia are oxycodone (brand names include Endone, OxyNorm) and tapentadol (Palexia).

In fact, about half of new oxycodone prescriptions in Australia occur after a recent hospital visit.

Most commonly, people will be given immediate-release opioids for their pain. These are quick-acting and are used to manage short-term pain.

Because they work quickly, their dose can be easily adjusted to manage current pain levels. Your doctor will provide instructions on how to adjust the dosage based on your pain levels.

Then there are slow-release opioids, which are specially formulated to slowly release the dose over about half to a full day. These may have “sustained-release”, “controlled-release” or “extended-release” on the box.

Slow-release formulations are primarily used for chronic or long-term pain. The slow-release form means the medicine does not have to be taken as often. However, it takes longer to have an effect compared with immediate-release, so it is not commonly used after surgery.

Controlling your pain after surgery is important. This allows you get up and start moving sooner, and recover faster. Moving around sooner after surgery prevents muscle wasting and harms associated with immobility, such as bed sores and blood clots.

Everyone’s pain levels and needs for pain medicines are different. Pain levels also decrease as your surgical wound heals, so you may need to take less of your medicine as you recover.

But there are also risks

As mentioned above, side effects of opioids include constipation and feeling drowsy or nauseous. The drowsiness can also make you more likely to fall over.

Opioids prescribed to manage pain at home after surgery are usually prescribed for short-term use.

But up to one in ten Australians still take them up to four months after surgery. One study found people didn’t know how to safely stop taking opioids.

Such long-term opioid use may lead to dependence and overdose. It can also reduce the medicine’s effectiveness. That’s because your body becomes used to the opioid and needs more of it to have the same effect.

Dependency and side effects are also more common with slow-release opioids than immediate-release opioids. This is because people are usually on slow-release opioids for longer.

Then there are concerns about “leftover” opioids. One study found 40% of participants were prescribed more than twice the amount they needed.

This results in unused opioids at home, which can be dangerous to the person and their family. Storing leftover opioids at home increases the risk of taking too much, sharing with others inappropriately, and using without doctor supervision.

How to mimimise the risks

Before using opioids, speak to your doctor or pharmacist about using over-the-counter pain medicines such as paracetamol or anti-inflammatories such as ibuprofen (for example, Nurofen, Brufen) or diclofenac (for example, Voltaren, Fenac).

These can be quite effective at controlling pain and will lessen your need for opioids. They can often be used instead of opioids, but in some cases a combination of both is needed.

Other techniques to manage pain include physiotherapy, exercise, heat packs or ice packs. Speak to your doctor or pharmacist to discuss which techniques would benefit you the most.

However, if you do need opioids, there are some ways to make sure you use them safely and effectively:

• ask for immediate-release rather than slow-release opioids to lower your risk of side effects
• do not drink alcohol or take sleeping tablets while on opioids. This can increase any drowsiness, and lead to reduced alertness and slower breathing
• as you may be at higher risk of falls, remove trip hazards from your home and make sure you can safely get up off the sofa or bed and to the bathroom or kitchen
• before starting opioids, have a plan in place with your doctor or pharmacist about how and when to stop taking them. Opioids after surgery are ideally taken at the lowest possible dose for the shortest length of time.

If you’re concerned about side effects

If you are concerned about side effects while taking opioids, speak to your pharmacist or doctor. Side effects include:

• constipation – your pharmacist will be able to give you lifestyle advice and recommend laxatives
• drowsiness – do not drive or operate heavy machinery. If you’re trying to stay awake during the day, but keep falling asleep, your dose may be too high and you should contact your doctor
• weakness and slowed breathing – this may be a sign of a more serious side effect such as respiratory depression which requires medical attention. Contact your doctor immediately.

If you’re having trouble stopping opioids

Talk to your doctor or pharmacist if you’re having trouble stopping opioids. They can give you alternatives to manage the pain and provide advice on gradually lowering your dose.

You may experience withdrawal effects, such as agitation, anxiety and insomnia, but your doctor and pharmacist can help you manage these.

How about leftover opioids?

After you have finished using opioids, take any leftovers to your local pharmacy to dispose of them safely, free of charge.

Do not share opioids with others and keep them away from others in the house who do not need them, as opioids can cause unintended harms if not used under the supervision of a medical professional. This could include accidental ingestion by children.

For more information, speak to your pharmacist or doctor. Choosing Wisely Australia also has free online information about managing pain and opioid medicines.

Katelyn Jauregui, PhD Candidate and Clinical Pharmacist, School of Pharmacy, Faculty of Medicine and Health, University of Sydney; Asad Patanwala, Professor, Sydney School of Pharmacy, University of Sydney; Jonathan Penm, Senior lecturer, School of Pharmacy, University of Sydney, and Shania Liu, Postdoctoral Research Fellow, Faculty of Medicine and Dentistry, University of Alberta

This article is republished from The Conversation under a Creative Commons license. Read the original article.