Saxenda (liraglutide 3.0 mg) is a GLP-1 receptor agonist licensed in the UK for weight management in adults and adolescents with obesity or overweight with comorbidities. Whilst Saxenda has well-documented side effects—primarily gastrointestinal symptoms such as nausea and diarrhoea—swollen lymph nodes are not recognised as an established adverse effect in the Summary of Product Characteristics or patient information leaflets. If lymphadenopathy occurs during Saxenda treatment, it is more likely coincidental, often related to common causes such as infection. This article examines the relationship between Saxenda and lymph node swelling, when to seek medical advice, and how to manage treatment safely.

Understanding Saxenda and Its Mechanism of Action

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 also licensed for adolescents aged 12 years and older with body weight above 60 kg and BMI equivalent to ≥30 kg/m². Saxenda is administered as a once-daily subcutaneous injection and should be used alongside a reduced-calorie diet and increased physical activity.

In the NHS, Saxenda is typically prescribed within specialist weight management services (Tier 3 or 4), with treatment generally limited to up to 2 years in accordance with NICE guidance (TA664).

The active ingredient, liraglutide, is a glucagon-like peptide-1 (GLP-1) receptor agonist. GLP-1 is a naturally occurring incretin hormone that plays several important roles in glucose homeostasis and appetite regulation. Saxenda works by mimicking the effects of endogenous GLP-1, binding to GLP-1 receptors in multiple tissues throughout the body, including the pancreas, gastrointestinal tract, and brain.

Through this mechanism, Saxenda:

• Slows gastric emptying, which prolongs the feeling of fullness after meals

• Reduces appetite by acting on appetite centres in the hypothalamus

• Enhances glucose-dependent insulin secretion from pancreatic beta cells

• Suppresses inappropriate glucagon secretion when blood glucose levels are elevated

These combined effects lead to reduced calorie intake and, consequently, weight loss. Clinical trials have demonstrated that Saxenda, when used as part of a comprehensive weight management programme, can result in clinically significant weight reduction.

According to the SmPC, treatment continuation depends upon achieving and maintaining adequate weight loss (at least 5% of initial body weight after 12 weeks at the maintenance dose of 3.0 mg daily). For adolescents, treatment should be discontinued and re-evaluated if body weight has not decreased by at least 4% after 12 weeks on the 3.0 mg dose.

Important precautions include contraindication in pregnancy and breastfeeding, and risk of dehydration that may lead to acute kidney injury, particularly in patients with pre-existing renal impairment.

Swollen Lymph Nodes: Causes and Clinical Significance

Lymph nodes are small, bean-shaped structures that form part of the lymphatic system, playing a crucial role in immune function. They filter lymph fluid, trapping bacteria, viruses, and other foreign substances, and contain lymphocytes (white blood cells) that help fight infection. Lymph nodes are distributed throughout the body, with clusters commonly found in the neck, armpits, groin, and abdomen.

Lymphadenopathy (swollen lymph nodes) occurs when lymph nodes become enlarged, typically measuring more than 1 cm in diameter. This enlargement can be localised (affecting one area) or generalised (involving multiple regions). The most common causes include:

• Infections: Viral infections (such as upper respiratory tract infections, glandular fever, or COVID-19) and bacterial infections (including streptococcal throat infections or skin infections) frequently cause reactive lymphadenopathy

• Inflammatory conditions: Autoimmune disorders like rheumatoid arthritis or lupus can trigger lymph node swelling

• Malignancies: Lymphomas, leukaemias, or metastatic cancer may present with persistent lymphadenopathy

• Medications: Certain drugs can occasionally cause lymph node enlargement as an adverse reaction

Clinically, the characteristics of swollen lymph nodes help determine their significance. Benign reactive lymphadenopathy typically presents with nodes that are mobile, tender, and associated with obvious infection. Conversely, concerning features include nodes that are hard, fixed, non-tender, progressively enlarging, or accompanied by unexplained weight loss, night sweats, or persistent fever.

According to NICE Clinical Knowledge Summary (CKS) on Lymphadenopathy, lymph nodes persisting beyond 3–4 weeks without obvious cause, or those with worrying characteristics, warrant further investigation to exclude serious underlying pathology. Supraclavicular lymphadenopathy is particularly concerning and requires urgent assessment regardless of duration, as outlined in NICE guideline NG12 for suspected cancer referral.

Is Lymph Node Swelling a Recognised Side Effect of Saxenda?

Lymph node swelling is not listed as a recognised or common adverse effect in the official Saxenda Summary of Product Characteristics (SmPC) approved by the MHRA or in patient information leaflets. The documented side effects of Saxenda primarily relate to its gastrointestinal effects and metabolic actions.

The most commonly reported adverse effects of Saxenda include:

• Gastrointestinal symptoms (very common, affecting more than 1 in 10 people): nausea, vomiting, diarrhoea, constipation, and abdominal pain. These typically occur during dose escalation and often diminish over time

• Hypoglycaemia: Particularly in patients taking Saxenda alongside other glucose-lowering medications

• Injection site reactions: Including redness, itching, or bruising at the injection site

• Headache, dizziness, and fatigue

• Increased heart rate: A small mean increase in resting heart rate is common; patients should report persistent tachycardia or palpitations

Serious adverse effects include pancreatitis and gallbladder disease. Preclinical studies in rodents showed thyroid C-cell tumours, though the relevance to humans remains uncertain according to the SmPC and European Public Assessment Report (EPAR). Rare hypersensitivity reactions can occur and could theoretically present with lymphadenopathy.

There is no established pharmacological mechanism by which liraglutide would directly cause lymphadenopathy based on current evidence in the SmPC.

If swollen lymph nodes occur during Saxenda treatment, this is more likely to be coincidental rather than causally related to the medication. The timing of symptom onset, presence of other symptoms (such as infection), and lymph node characteristics should be carefully evaluated. Any persistent or concerning lymphadenopathy requires thorough clinical assessment to identify the underlying cause, which may be entirely unrelated to Saxenda therapy.

Patients who suspect they may be experiencing side effects from Saxenda should report these to the MHRA through the Yellow Card Scheme.

When to Seek Medical Advice About Swollen Lymph Nodes

Patients taking Saxenda who notice swollen lymph nodes should be aware of when medical evaluation is necessary. Whilst many cases of lymphadenopathy are benign and self-limiting, certain features warrant prompt medical attention.

You should contact your GP or healthcare provider if you experience:

• Lymph nodes that persist for more than 3–4 weeks without improvement, particularly if there is no obvious infection

• Progressive enlargement of lymph nodes over time

• Hard, fixed, or non-tender lymph nodes that do not move easily under the skin

• Lymph nodes larger than 2 cm in diameter

• Supraclavicular lymphadenopathy (swollen nodes above the collarbone), which requires urgent assessment

• Multiple areas of lymph node swelling (generalised lymphadenopathy)

• Accompanying symptoms such as unexplained weight loss (beyond expected weight loss from Saxenda), drenching night sweats, persistent fever, or extreme fatigue

• Difficulty breathing or swallowing if lymph nodes in the neck are significantly enlarged

Immediate medical attention (same-day GP appointment or A&E) is warranted if swollen lymph nodes are accompanied by:

• Severe difficulty breathing or swallowing

• Signs of severe infection (high fever, rigors, severe pain)

• Rapidly progressive swelling

Your GP will conduct a thorough clinical assessment, including examination of the lymph nodes and evaluation for signs of infection or other underlying conditions. According to NICE guidance, investigations may include blood tests (full blood count, inflammatory markers, specific infection serology), ultrasound imaging, or referral for specialist assessment if concerning features are present.

Lymphadenopathy with features suspicious for cancer may require an urgent two-week wait referral in line with NICE guideline NG12 for suspected cancer.

It is important to inform your healthcare provider about all medications you are taking, including Saxenda, as this provides context for your clinical presentation. However, remember that lymph node swelling during Saxenda treatment is more likely related to common causes such as infection rather than the medication itself.

Managing Side Effects and Monitoring During Saxenda Treatment

Effective management of Saxenda therapy requires regular monitoring and open communication with healthcare professionals to optimise treatment outcomes whilst minimising adverse effects.

Routine monitoring during Saxenda treatment should include:

• Weight and BMI measurements: Regular assessment (typically monthly initially) to evaluate treatment response

• Blood glucose monitoring: Particularly important for patients with type 2 diabetes or prediabetes, as Saxenda may affect glycaemic control

• Heart rate: Saxenda can cause modest increases in resting heart rate; patients should report palpitations or persistent tachycardia

• Mood changes: Monitor for new or worsening depression or suicidal thoughts; seek medical help promptly if these occur

• Gallbladder symptoms: Be alert for signs of gallstones or cholecystitis (severe upper abdominal pain, particularly after meals)

• Pancreatitis symptoms: Seek immediate medical attention for severe, persistent abdominal pain radiating to the back

Managing common gastrointestinal side effects:

• Follow the gradual dose escalation schedule (starting at 0.6 mg daily, increasing weekly by 0.6 mg increments to the maintenance dose of 3.0 mg). A slower escalation may be needed if side effects are troublesome

• Eat smaller, more frequent meals and avoid high-fat foods

• Stay well hydrated, particularly if experiencing vomiting or diarrhoea, to reduce the risk of dehydration and acute kidney injury

• Take the injection at a consistent time that minimises symptom impact

Treatment continuation criteria, aligned with NICE guidance (TA664), recommend:

• Assessing weight loss after 12 weeks at the 3.0 mg maintenance dose

• Continuing treatment only if at least 5% of initial body weight has been lost

• Discontinuing Saxenda if adequate weight loss is not achieved or maintained

• Treatment typically limited to up to 2 years within specialist weight management services

Patient safety considerations include proper injection technique, rotating injection sites to prevent lipodystrophy, and appropriate medication storage (refrigerated before first use, then at room temperature for up to one month).

If you experience any side effects, including those not listed in the patient information leaflet, report them to your healthcare provider and consider submitting a report through the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

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