Saxenda (liraglutide 3.0 mg) is a GLP-1 receptor agonist licensed in the UK for weight management in adults with obesity or overweight with comorbidities. Concerns have emerged about potential links between GLP-1 medications and diabetic retinopathy, particularly following clinical trial data on related drugs. Whilst Saxenda's UK product information does not contain a specific retinopathy warning, rapid improvements in blood glucose—a known effect of GLP-1 agonists—may temporarily worsen pre-existing retinal disease. This article examines the evidence, identifies at-risk patients, and outlines monitoring strategies to support safe Saxenda use in individuals with diabetes and eye health concerns.

What Is Saxenda and How Does It Work?

Saxenda (liraglutide 3.0 mg) is a prescription medicine licensed in the UK for weight management in adults with obesity (BMI ≥30 kg/m²) or overweight (BMI ≥27 kg/m²) with at least one weight-related comorbidity such as type 2 diabetes, hypertension, or dyslipidaemia. It is administered as a once-daily subcutaneous injection and is intended to be used alongside a reduced-calorie diet and increased physical activity.

Liraglutide belongs to a class of medications called glucagon-like peptide-1 (GLP-1) receptor agonists. These drugs mimic the action of the naturally occurring hormone GLP-1, which is released from the intestine after eating. By binding to GLP-1 receptors in the brain, particularly in areas that regulate appetite, Saxenda helps to reduce hunger and increase feelings of fullness. This mechanism supports patients in achieving and maintaining weight loss over time.

Saxenda is initiated at a dose of 0.6 mg daily and gradually titrated weekly (0.6 mg, 1.2 mg, 1.8 mg, 2.4 mg, 3.0 mg) to minimise gastrointestinal side effects. Treatment should be discontinued after 12 weeks at the 3.0 mg daily dose if patients have not lost at least 5% of their initial body weight. Importantly, while Saxenda may improve glycaemic control, it is specifically licensed for weight management, not for the treatment of diabetes. Patients should not use Saxenda concurrently with other GLP-1 receptor agonists.

Saxenda is approved by the Medicines and Healthcare products Regulatory Agency (MHRA) and is available on the NHS in specific circumstances according to NICE Technology Appraisal 664. NHS eligibility typically requires a BMI of 35 kg/m² or above (32.5 kg/m² in certain ethnic groups) with a weight-related comorbidity, and previous completion of a multicomponent weight management programme. Access may vary depending on local commissioning decisions.

Understanding Diabetic Retinopathy and Its Risk Factors

Diabetic retinopathy is a microvascular complication of diabetes mellitus and remains one of the leading causes of preventable blindness in working-age adults in the UK. It occurs when persistently elevated blood glucose levels damage the small blood vessels in the retina—the light-sensitive tissue at the back of the eye. Over time, these vessels may leak fluid, bleed, or become blocked, leading to vision impairment.

The condition progresses through stages, beginning with non-proliferative diabetic retinopathy (NPDR), characterised by microaneurysms, haemorrhages, and exudates. If left unmanaged, it can advance to proliferative diabetic retinopathy (PDR), where new, fragile blood vessels grow abnormally on the retina's surface. These vessels are prone to bleeding and can cause retinal detachment or severe vision loss. Diabetic macular oedema (DMO), where fluid accumulates in the macula, can occur at any stage and significantly affects central vision.

Key risk factors for developing diabetic retinopathy include:

• Duration of diabetes: The longer someone has diabetes, the higher their risk

• Poor glycaemic control: Elevated HbA1c levels accelerate retinal damage

• Hypertension: High blood pressure exacerbates microvascular complications

• Dyslipidaemia: Abnormal cholesterol levels contribute to retinal vessel disease

• Rapid improvement in blood glucose: Paradoxically, very quick reductions in HbA1c can temporarily worsen retinopathy

• Pregnancy: Gestational changes can accelerate retinopathy progression

• Smoking and kidney disease: Both independently increase risk

The NHS Diabetic Eye Screening Programme offers annual retinal photography to all people with diabetes aged 12 and over, enabling early detection and timely intervention. NICE guidelines emphasise the importance of optimal diabetes management, blood pressure control, and regular screening to prevent or delay retinopathy progression.

The Link Between Saxenda and Diabetic Retinopathy

Concerns about a potential association between GLP-1 receptor agonists and diabetic retinopathy emerged following clinical trial data, particularly from studies of semaglutide (a related GLP-1 analogue). The SUSTAIN-6 trial reported an increased incidence of diabetic retinopathy complications in patients treated with semaglutide compared to placebo, prompting regulatory scrutiny and further investigation into the class effect.

It is important to note that, unlike semaglutide products (Ozempic, Wegovy), Saxenda's UK product information does not contain a specific warning about diabetic retinopathy. The semaglutide signal has, however, raised clinical awareness about the potential for retinopathy changes with GLP-1 receptor agonists as a class, particularly in patients with pre-existing retinal disease.

The proposed mechanism is not that liraglutide directly damages the retina, but rather that rapid improvements in glycaemic control—a known effect of GLP-1 agonists—may temporarily worsen existing retinopathy. This phenomenon, sometimes called "early worsening," has been documented with intensive insulin therapy in landmark diabetes studies such as the DCCT and UKPDS.

When blood glucose levels drop quickly after years of poor control, the retinal vessels, already damaged by chronic hyperglycaemia, may experience acute changes in perfusion and oxygenation. This can lead to increased vascular permeability, haemorrhage, or progression of proliferative changes. It is important to emphasise that this represents a transient risk associated with rapid metabolic improvement rather than a direct toxic effect of the medication itself.

While there are no formal MHRA or EMA recommendations specific to liraglutide and retinopathy monitoring, clinicians should consider the potential for early worsening in patients with pre-existing retinopathy who may experience significant glycaemic improvement with Saxenda, particularly if they have diabetes.

Clinical Evidence and Safety Data from UK Studies

The evidence base regarding Saxenda and diabetic retinopathy comes primarily from clinical trials and post-marketing surveillance data. The LEADER trial, a large cardiovascular outcomes study of liraglutide 1.8 mg (the dose used for type 2 diabetes, lower than Saxenda's 3.0 mg dose), included over 9,000 patients followed for a median of 3.8 years. This study, published in the New England Journal of Medicine, did not demonstrate a significant increase in diabetic retinopathy complications compared to placebo, although retinopathy was not a primary endpoint.

Data from trials of higher-dose GLP-1 agonists have prompted ongoing vigilance. The SUSTAIN-6 trial with semaglutide showed a higher rate of retinopathy complications, particularly in patients with pre-existing retinopathy and those experiencing rapid HbA1c reductions. Some systematic reviews have examined this issue across GLP-1 receptor agonist trials, with varying conclusions about the magnitude and consistency of any association.

Observational studies, including some UK-based research, continue to evaluate real-world patterns of GLP-1 agonist use and complications. These studies generally support the safety profile observed in clinical trials but emphasise the importance of individualised risk assessment. Patients with longstanding diabetes, poor baseline glycaemic control, and known retinopathy appear to be at higher risk of early worsening.

While NICE guidance on GLP-1 receptor agonists for type 2 diabetes (NG28) does not specifically address retinopathy risk, the Royal College of Ophthalmologists' guidelines on diabetic retinopathy acknowledge the potential for early worsening with rapid glycaemic improvement. Clinical practice has evolved to consider baseline retinal status when initiating treatments that may substantially improve glycaemic control. Regular communication between diabetes specialists, ophthalmologists, and GPs is essential to ensure coordinated care and appropriate monitoring.

Who Should Avoid Saxenda Due to Eye Health Concerns?

While diabetic retinopathy is not listed as a contraindication in the Saxenda Summary of Product Characteristics, certain individuals may require careful evaluation and enhanced monitoring before and during treatment. The decision to prescribe Saxenda should involve a thorough assessment of the patient's diabetes history, current retinal status, and overall risk-benefit profile.

Patients who may need additional assessment before starting Saxenda include:

• Those with active proliferative diabetic retinopathy (PDR): Patients with new vessel formation, vitreous haemorrhage, or recent retinal laser treatment may be at increased risk of early worsening if glucose levels improve rapidly

• Individuals with severe non-proliferative retinopathy: Those approaching the proliferative stage may benefit from ophthalmological input before initiating therapy

• Patients with diabetic macular oedema requiring active treatment: Unstable macular oedema may potentially be affected by rapid metabolic changes

• Those with very poor baseline glycaemic control (HbA1c >10%): Rapid glucose reduction in this group may carry higher risk and should be managed with appropriate monitoring

It is important to note that having diabetic retinopathy does not automatically preclude Saxenda use. Many patients with mild to moderate non-proliferative retinopathy can safely use the medication with appropriate monitoring. The key is to identify high-risk individuals and ensure they receive baseline ophthalmological assessment and regular follow-up.

Patients should inform their prescriber if they have any history of eye problems related to diabetes, including previous laser treatment, injections into the eye, or vision changes. A recent retinal screening result (within the past 6–12 months) should ideally be available before starting Saxenda. If there are concerns about retinal status, referral to an ophthalmologist for detailed assessment may be appropriate before treatment initiation.

Remember that Saxenda should not be used concurrently with other GLP-1 receptor agonists.

Monitoring and Managing Retinopathy Risk While Using Saxenda

For patients deemed suitable for Saxenda treatment, particularly those with diabetes or pre-existing retinopathy, a structured approach to monitoring and risk management is essential. This involves collaboration between the prescribing clinician, the patient's diabetes care team, and ophthalmology services where appropriate.

Baseline assessment should include:

• Recent retinal screening: Ensure participation in the NHS Diabetic Eye Screening Programme and review the most recent results

• HbA1c measurement: Document baseline glycaemic control to anticipate the rate of improvement

• Blood pressure and lipid profile: Optimise cardiovascular risk factors that also affect retinal health

• Ophthalmology referral if indicated: Consider specialist assessment for patients with moderate to severe retinopathy or those who have not had recent screening

During treatment, patients should:

• Continue annual diabetic eye screening: Do not miss scheduled appointments, as early detection of changes is crucial

• Report visual symptoms promptly: Any new floaters, flashing lights, blurred vision, or visual field loss should trigger urgent ophthalmology review

• Follow the recommended Saxenda titration schedule: The standard weekly titration helps minimise side effects while achieving the therapeutic dose

• Maintain optimal blood pressure control: Target <140/90 mmHg generally, or <130/80 mmHg if kidney, eye or cerebrovascular damage is present, as per NICE guidance

Healthcare professionals should:

• Monitor HbA1c every 3–6 months: Track the rate of glucose improvement and adjust treatment if necessary

• Consider additional retinal screening: Follow ophthalmologist recommendations for monitoring frequency in high-risk patients

• Coordinate care: Ensure clear communication between primary care, diabetes services, and ophthalmology

• Discontinue Saxenda if less than 5% weight loss is achieved after 12 weeks at the 3.0 mg daily dose

Patients should be reassured that with appropriate monitoring and management, the benefits of Saxenda for weight loss and metabolic health can be achieved safely. If retinopathy does worsen, ophthalmological interventions such as laser photocoagulation or anti-VEGF injections remain effective treatments. The key message is that awareness, monitoring, and timely intervention enable safe use of Saxenda in the majority of patients, including many with diabetic retinopathy.

Patients and healthcare professionals are encouraged to report suspected adverse reactions to Saxenda via the MHRA Yellow Card scheme.

Frequently Asked Questions