Developed in collaboration with CASA Medical.
The medications of the class “Glucagon-Like Peptide-1 receptor agonists” or GLP-1RAs are prescribed for the management of obesity. In NZ liraglutide and semaglutide are approved by Medsafe for weight management. Three GLP-1RAs have been approved by the Australian Therapeutic Goods Administration: semaglutide, liraglutide and tirzepatide. There are a number of brands and formulations of these agents. They all share the same mechanism of action and have similar effectiveness and side effect profiles.
This guideline refers to the use of GLP-1RAs for weight management. Please refer to the Diabetes CPG for information on the use of GLP-1RAs in the management of Diabetes.
GLP-1RAs work by regulating glucose and appetite. Glucose levels are regulated by stimulating natural insulin secretion when blood sugar is high. Appetite is regulated through actions on the way the brain perceives hunger and cravings, and the sense of satisfaction from eating.
Side effects are common but usually of mild severity. Most often people experience gastrointestinal side effects of nausea, vomiting, diarrhoea or constipation. In some cases these are severe enough for the person to be unable to perform their usual daily activities, so they are forced to reduce their dose or stop using the medication altogether. Rarely people can have problems relating to gall stones and the gall bladder system (gall stones, gall bladder inflammation or infection), or inflammation of the pancreas. Reports of mental health complications have not been confirmed by researchers. Low blood sugar is not of concern when the medication is used for weight management in people who are not also taking other medications for diabetes.
The aeromedical safety relevance of GLP-1RAs is related to the experience of acute and severe nausea, vomiting and diarrhoea, or pain related to biliary and pancreatic complications. Gastrointestinal symptoms are a common cause of in-flight impairment for pilots. If any of these are experienced, the license-holder must cease their aviation duties and seek advice from their treating doctor. Return to aviation duties will depend on the type and severity of the event.
The reduction in energy and nutritional intake associated with the effect of GLP-1RAs may also be safety relevant for aviation, and license-holders should be counselled and investigated accordingly. Consideration should be given to testing iron studies, vitamin D, calcium, B12 and folate. Loss of muscle mass and reduced bone density may also be an issue that becomes safety relevant in some operational situations.
Environmental factors experienced while flying can worsen the gastrointestinal side effects of GLP-1RAs. Mild or minimal nausea might become more severe due to the nauseogenic influence of turbulence, aerobatic manoeuvres, vestibular illusions or spatial disorientation.
Vomiting can cause pilots and controllers to be unable to see, speak, hear or act during the episode of vomiting and the immediate aftermath.
Recurrent or persistent vomiting may cause hyperventilation, which can lead to altered consciousness, sensory changes and muscle incoordination rendering a person unable to perform any aviation tasks.
Muscle mass and G tolerance – sudden weight loss may reduce muscle mass significantly, which reduces G tolerance even at low-G exposures and may reduce the effectiveness of the anti-G straining manoeuvre. This may lead to A-LOC or G-LOC. This is particularly concerning for people who already at risk for sarcopenia.
Bone density and crashworthiness / survivability. Rapid weight loss may cause changes in bone density due to demineralisation. Pilots may be at risk of minimal-trauma fracture during events such as severe turbulence or heavy landings. They may be rendered unable to fly or perform the emergency procedures required of their license or role. This is particularly concerning for people who are already at risk for or diagnosed with osteopenia or osteoporosis.
Pre-syncope and syncope (light-headedness and fainting) may occur due to acute or sustained restriction of food and fluid intake. The altered conscious state, even if consciousness is not lost, may render the person unable to perform their aviation duties.
Nausea can be deeply unpleasant and distract a person from their primary aviation task while they attempt to manage the sensation and reduce the likelihood of nausea progressing to frank vomiting.
Diarrhoea affecting a person during their aviation duties will distract them from performing their primary aviation tasks while they attempt to manage the acute episode, or may lead to unsafe decisions for example related to perceived pressure to land to manage a current or impending episode.
Pain due to constipation (possible worsened by trapped gas expansion), acute gall bladder disease or pancreatitis can be sudden and severe, and mild pain can increase over very short times and progress to being entirely incapacitating. Affected people may not perform their primary aviation tasks while they attempt to manage the acute episode, or may lead to unsafe decisions for example related to perceived pressure to land to manage their pain.
Nutritional deficiency may cause impaired cognitive and executive function (memory, decision-making, threat and error management) as the micro and macro-nutrient, energy and water intake required for normal function of body systems, and the brain in particular, are inadequate.
Energy deficiency due to absolute lack of calories can cause fatigue, lack of endurance, poor concentration and irritability.
Hypohydration due to restricted food and fluid intake can also cause cognitive impairment, fatigue, dizziness or fainting (see above).
Pilots or controllers who have commenced treatment (or intend to) must cease aviation duties for at least two weeks, and be cleared by a ME to return to aviation duties. New applications from people using GLP-1RAs must also provide this information with their initial application regardless of when the medication was started.
The ME must provide a letter to CAA including:
A CAA clearance must also be provided if any persistent (more than 7 days for Class 1 and 3, more than 30 days for Class 2) or severe adverse effects (of any duration) have been experienced. The pilot or controller must provide a letter from their treating doctor or ME including:
When a pilot or controller is continuing to use GLP-1RAs, at the time of their application for medical certificate renewal, the ME or treating doctor must provide CAA the following information.
The information required at renewal is:
If ALL the criteria are met the ME may issue a pilot or controller a medical certificate.
| ME must confirm | Tick |
|---|---|
| No diagnosis of diabetes (HbA1c or OGTT) | 
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| No adverse symptoms / side effects |
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| No complications of treatment |
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| No nutritional deficiencies |
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Counselling provided
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Appropriate use / no contra-indications
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| ME considers safe to certify |
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An AMC referral to CAA NZ Aviation Medicine teams is required if a pilot’s or controller’s condition does not meet all the above criteria and they consent to their condition being considered under flexibility to the CAR 67 rules.
Request a report from participants after starting medication [DOCX 23 KB]
