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. Whilst gastrointestinal side effects are common, questions have arisen regarding Saxenda side effects eye-related concerns. Eye-related adverse effects are not commonly listed in the Summary of Product Characteristics, and direct ocular side effects are rare. However, patients with diabetes may experience visual changes related to glycaemic fluctuations rather than direct drug effects. Understanding the distinction between medication effects and underlying disease progression is essential for safe treatment monitoring.

Understanding Saxenda and Potential Eye-Related Side Effects

Saxenda (liraglutide 3.0 mg) is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for weight management in adults with a body mass index (BMI) of 30 kg/m² or greater, or 27 kg/m² or greater with weight-related comorbidities. Administered as a once-daily subcutaneous injection, Saxenda works by mimicking the action of the naturally occurring hormone GLP-1, which regulates appetite and food intake by acting on receptors in the brain, pancreas, and gastrointestinal tract.

Whilst Saxenda is generally well-tolerated, patients and healthcare professionals should be aware of its full adverse effect profile. The most commonly reported side effects include gastrointestinal symptoms such as nausea, vomiting, diarrhoea, and constipation. However, questions have arisen regarding potential eye-related side effects. It's important to note that Saxenda is licensed specifically for weight management, not for glycaemic control, although weight loss may influence blood glucose levels in people with diabetes.

Eye-related adverse effects are not commonly listed among the frequent side effects of Saxenda in the Summary of Product Characteristics (SmPC) approved by the Medicines and Healthcare products Regulatory Agency (MHRA). Clinical vigilance is warranted, especially in patients with pre-existing diabetes or those at risk of diabetic complications, as diabetic eye disease is primarily related to the underlying condition rather than a direct medication effect. Understanding the distinction between direct drug effects and underlying disease progression is essential when evaluating any visual symptoms that emerge during treatment.

This article examines the evidence surrounding eye-related concerns with Saxenda, explores the potential mechanisms involved, and provides guidance on monitoring and managing eye health during treatment.

Common Eye Symptoms Reported with Saxenda Use

Direct eye-related side effects specifically attributed to Saxenda are uncommon, and there is no official link established between liraglutide use for weight management and routine visual disturbances in the general population. However, some patients have anecdotally reported subjective visual symptoms during treatment, which may include:

• Blurred vision – typically transient and often related to fluctuations in blood glucose levels, particularly in patients with diabetes or prediabetes

• Dry eyes – not a recognised adverse effect in clinical trials or listed in the SmPC, but occasionally reported anecdotally and possibly related to dehydration from gastrointestinal side effects

• Eye discomfort or irritation – non-specific symptoms that may coincide with treatment initiation

• Visual changes – rare reports of altered visual acuity or perception

It is important to note that many of these symptoms may not be directly caused by Saxenda itself but could reflect underlying metabolic changes, concurrent medications, or pre-existing conditions. For instance, rapid improvements in glycaemic control—which can occur when Saxenda is used in patients with type 2 diabetes or prediabetes—may temporarily affect the refractive properties of the lens, leading to transient blurred vision. This phenomenon is well-documented with various diabetes treatments and typically resolves as glucose levels stabilise.

Dehydration, a potential consequence of gastrointestinal side effects such as vomiting and diarrhoea, may also contribute to dry eye symptoms. Patients experiencing significant fluid loss should ensure adequate hydration and discuss persistent symptoms with their GP or prescribing clinician.

Hypoglycaemia, particularly when Saxenda is used alongside insulin or sulfonylureas in people with diabetes, can also cause transient visual symptoms. This is an important consideration for patients with diabetes who are taking multiple glucose-lowering medications.

Whilst these symptoms are generally mild and self-limiting, any persistent or worsening visual changes warrant medical evaluation to exclude more serious underlying causes and to differentiate between drug-related effects and disease progression.

Diabetic Retinopathy Risk and GLP-1 Receptor Agonists

The relationship between GLP-1 receptor agonists and diabetic retinopathy has received considerable attention following findings from the SUSTAIN-6 trial, which evaluated semaglutide (another GLP-1 receptor agonist) in patients with type 2 diabetes. This study identified a numerical increase in diabetic retinopathy complications in the semaglutide group compared with placebo, particularly among patients with pre-existing retinopathy and those experiencing rapid glycaemic improvement.

The proposed mechanism involves rapid reduction in blood glucose levels, which may temporarily worsen retinopathy through alterations in retinal blood flow and oxygenation. This phenomenon, known as "early worsening," has been observed with intensive insulin therapy and is not unique to GLP-1 receptor agonists.

It is important to clarify that this retinopathy signal was observed specifically with semaglutide, and the semaglutide SmPC (Ozempic, Wegovy) carries specific warnings about retinopathy risk. This warning is not present in the liraglutide (Saxenda) SmPC, as a similar signal was not demonstrated in liraglutide clinical trials.

It is crucial to emphasise that Saxenda is primarily used for weight management in a broader population, many of whom do not have diabetes. The diabetic retinopathy concerns identified in diabetes trials may have limited applicability to non-diabetic Saxenda users. For patients with type 2 diabetes using Saxenda, vigilance is appropriate, particularly in those with:

• Pre-existing diabetic retinopathy – particularly proliferative or severe non-proliferative disease

• Rapid improvement in glycaemic control – following treatment initiation

• Long-standing poorly controlled diabetes – with multiple microvascular complications

NICE guidance recommends regular diabetic eye screening for all patients with diabetes, regardless of treatment. Patients with diabetes starting Saxenda should ensure they are enrolled in the NHS Diabetic Eye Screening Programme and attend annual appointments. Those with known retinopathy may require more frequent ophthalmological monitoring, particularly during the initial months of treatment when glycaemic changes are most pronounced.

When to Seek Medical Advice About Eye Changes on Saxenda

Patients taking Saxenda should be advised to seek prompt medical attention if they experience any significant or persistent visual symptoms. Whilst most eye-related concerns are likely to be benign or unrelated to the medication, certain warning signs require urgent evaluation to exclude serious conditions.

Contact your GP or prescribing clinician if you experience:

• Sudden vision loss or significant deterioration in visual acuity in one or both eyes

• Persistent blurred vision that does not improve after several days or worsens over time

• Floaters or flashing lights – particularly if sudden in onset, as these may indicate retinal detachment

• Dark spots or shadows in your visual field

• Eye pain accompanied by visual changes, redness, or sensitivity to light

• Double vision or difficulty focusing

For patients with diabetes, any new visual symptoms should be reported promptly, as they may indicate progression of diabetic retinopathy or other microvascular complications. Do not wait for your next routine screening appointment if you notice changes.

For urgent concerns that are not life-threatening, contact NHS 111 for advice. In some areas, Community Urgent Eyecare Services (CUES) or Minor Eye Conditions Services (MECS) may be available through local optometrists.

Seek emergency care (attend A&E or call 999) if you experience:

• Sudden, painless vision loss – this may indicate retinal artery or vein occlusion, or retinal detachment

• Severe eye pain with nausea, vomiting, or headache – potential signs of acute angle-closure glaucoma

• Sudden onset of multiple floaters with flashing lights – possible retinal tear or detachment

It is important to maintain open communication with your healthcare team throughout Saxenda treatment. Do not discontinue Saxenda without medical advice if you experience visual symptoms, as abrupt cessation may affect weight management goals. Your clinician can assess whether symptoms are related to the medication, require investigation, or necessitate treatment modification.

If you suspect an adverse reaction to Saxenda, you or your healthcare professional can report it through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk or the Yellow Card app).

Managing and Monitoring Eye Health During Saxenda Treatment

Proactive monitoring and management of eye health can help minimise risks and ensure early detection of any complications during Saxenda treatment. The following strategies are recommended for patients and healthcare professionals:

Before starting Saxenda:

• Comprehensive medical history – document any pre-existing eye conditions, diabetes status, and history of diabetic retinopathy

• Baseline eye assessment – patients with diabetes should have recent diabetic eye screening results reviewed; those with known or suspected retinopathy may benefit from ophthalmology review before treatment initiation

• Risk stratification – identify patients at higher risk (pre-existing retinopathy, poor glycaemic control, long diabetes duration) who may require enhanced monitoring

During Saxenda treatment:

• Regular diabetic eye screening – patients with diabetes must continue annual screening through the NHS Diabetic Eye Screening Programme

• Gradual dose titration – following the recommended dose escalation schedule (starting at 0.6 mg daily and increasing weekly) as outlined in the Saxenda SmPC may help minimise rapid metabolic changes

• Glycaemic monitoring – for patients with diabetes, monitor glycaemic changes and be vigilant for symptoms in those with pre-existing retinopathy; management should follow diabetes guidelines

• Hydration and symptom management – maintain adequate fluid intake, particularly if experiencing gastrointestinal side effects

• Patient education – ensure patients understand warning signs and know when to seek medical advice

Ongoing management considerations:

• Routine optometry appointments – encourage regular eye examinations with an optometrist, who can detect early changes in vision or ocular health

• Medication review – if persistent visual symptoms occur, consider whether other medications or conditions may be contributing

• Specialist referral – patients with concerning symptoms or known retinopathy should be referred to ophthalmology for specialist assessment

For most patients without diabetes or pre-existing eye disease, the risk of eye-related complications with Saxenda is very low. Maintaining good overall health, attending routine screening appointments, and promptly reporting any visual changes will help ensure safe and effective treatment. Healthcare professionals should provide clear safety-netting advice and maintain a low threshold for investigation of visual symptoms, particularly in higher-risk patients.

Frequently Asked Questions