Advice to patients
Injectable incretin treatments (also known as weight management medicines) help support weight loss in patients with high Body Mass Index (BMI). These treatments include a type called Glucagon-like peptide-1 receptor agonists or GLP1 for short.
NHS Greater Glasgow and Clyde are aware that some patients are accessing these treatments from private (non-NHS) suppliers and would like to provide some additional information which may be helpful to your care.
Use of these medicines works best for patients who are obese and will help a controlled loss of weight. They should not be used for those with a healthy weight nor as an aid for short term weight loss as there is no evidence to support use in these scenarios.
Prescription Only Medicines
These medications are prescription-only and must be prescribed by a registered healthcare professional. They should only be used by the person named on the prescription and under medical supervision.
Using someone else’s medication is unsafe and illegal.
When used correctly and for the right reasons, these treatments are safe. However, using them without proper medical oversight, especially in people with a healthy or low BMI, is associated with clinical risk, as the side effects and effectiveness in these groups are unknown.
Private Supplies of Weight Management Medication
If you choose to get weight management medication from a private provider, it’s important to make sure:
- The provider is legally registered, and the medication is licensed.
- You do not buy from unlicensed sources like beauty salons or social media.
- You speak to a healthcare professional before starting treatment.
Private providers do not have access to your full medical history, so they must carry out a full risk assessment before prescribing. The safest way to make sure your medication is legal and safe is to have it dispensed by a registered pharmacy.
If you are using weight management medication from a private source, please tell your GP practice. It is the responsibility of the private provider to assess whether these are safe for you to use, your GP practice does not have capacity to double check this assessment. The practice will usually add these on to your medicines record. This helps keep your medical records up to date and ensures any other treatments you receive are safe and appropriate—especially if your weight changes or you’re prescribed other medications.
Counterfeit Medicines
There are also reports of counterfeit versions of these medicines. These are illegal and may not contain the correct ingredients or doses. Using counterfeit medicines can be dangerous, as there is no quality control or guarantee of safety.
Who Should Not Use These Medications?
These treatments are being considered for people with a BMI of 38 or higher with at least one obesity-related condition (as per Scottish Government Phase 1 rollout guidance). NHSGGC are working to establish pathways for patients who will meet this criteria.
They are not suitable for weight management for people with:
- • A history of pancreatitis
- Severe kidney or liver disease
- Frailty or advanced age
- Severe mental health conditions
- Diabetic eye disease which requires treatment.
- T2 diabetes on insulin unless under the supervision of a diabetes specialist team.
- T1 diabetes.
These medications should not be used during pregnancy, while trying to conceive, or when breastfeeding.
Using these medications without proper medical supervision can worsen existing health problems and lead to serious side effects.
Drug Interactions
Some medications can interact with weight management medicines, so it is important patients are aware of the risks. As private providers must carry out a full health assessment before prescribing, this will check for any risks or interactions with other medications. Some GP practices have reported that patients were not informed about important interactions, such as with contraception.
Contraception
- Tirzepatide (Mounjaro®) may reduce the effectiveness of oral contraceptives.
- Women are advised to use a non-oral contraceptive (e.g. patch, implant, IUD) for 4 weeks after starting or increasing the dose.
- Women of childbearing age should use effective contraception during treatment and for a few months after stopping.
Hormone Replacement Therapy (HRT)
- These medicines may affect how well oral HRT works.
- Patches or vaginal products are preferred for oestrogen, as they bypass the stomach.
- It’s unclear if progesterone in HRT is affected.
Other Medications
Because these medicines slow down how quickly the stomach empties, they can affect how other medicines are absorbed. This includes:
- Warfarin (blood thinner)
- Digoxin (used for heart conditions)
These medicines may need closer monitoring to ensure the dose remains safe. Please speak to your pharmacist for advice.
Side Effects
Like most medicines, weight loss medicines can cause side effects. The most common ones include:
- Nausea
- Vomiting
- Constipation or diarrhoea
- Headache
These side effects are usually mild and go away on their own. If they don’t improve or get worse, patients should get medical advice, ideally from the healthcare professional who prescribed the medication.
Serious Side Effects
A rare but serious side effect is pancreatitis. If you experience severe stomach pain that spreads to your back and doesn’t go away, get urgent medical help.
Tips for Safe Use
To reduce side effects and support your health while on treatment:
- Stay well hydrated
- Eat small, regular meals
- Include protein in each meal
- Stay active to maintain muscle
- Eat a varied diet to avoid nutrient deficiencies
Further information
You can find more information via the following resouces:
Update
NHS Greater Glasgow and Clyde is currently developing a safe and effective local process for using these medications. When finalised, some patients with certain long-term conditions will have access to these medications. These patients will be assessed and monitored by specialist teams responsible for the patient’s care, who will also manage prescribing.