Can Saxenda cause hives? Yes, Saxenda (liraglutide) can cause hives, though this is an uncommon adverse reaction. Hives, medically termed urticaria, are raised, itchy welts that may indicate a hypersensitivity response to the medication. Saxenda is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed for weight management in adults and adolescents with obesity. According to the Medicines and Healthcare products Regulatory Agency (MHRA), allergic reactions including urticaria affect fewer than 1 in 100 patients. If you develop hives whilst taking Saxenda, withhold further doses and seek urgent medical advice, as this may occasionally herald more serious allergic reactions.

Can Saxenda Cause Hives?

Yes, Saxenda (liraglutide) can cause hives, though this is considered an uncommon adverse reaction. Hives, medically termed urticaria, are raised, itchy welts on the skin that can appear as a manifestation of an allergic or hypersensitivity reaction to the medication. According to the Summary of Product Characteristics (SmPC) approved by the Medicines and Healthcare products Regulatory Agency (MHRA), allergic reactions including urticaria have been reported in patients using Saxenda, affecting fewer than 1 in 100 patients.

Saxenda is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed for weight management in adults with a body mass index (BMI) of 30 kg/m² or greater, or 27 kg/m² or greater in the presence of weight-related comorbidities. It is also licensed for adolescents aged 12-17 years with obesity and body weight above 60 kg. The medication works by mimicking the action of the naturally occurring hormone GLP-1, which regulates appetite and food intake. Whilst Saxenda is generally well-tolerated, like all medications it can trigger immune-mediated reactions in susceptible individuals.

The development of hives may indicate a hypersensitivity response to one or more components of the medication, which may include the active ingredient liraglutide or excipients within the formulation. Importantly, Saxenda is contraindicated in patients with known hypersensitivity to liraglutide or any of the excipients. It is important to distinguish between mild, self-limiting skin reactions and more serious allergic responses that may require immediate medical attention. Patients who develop hives should not dismiss this symptom, as it may occasionally herald more severe hypersensitivity reactions. Never restart Saxenda after a suspected hypersensitivity reaction unless specifically advised to do so by a healthcare professional.

Understanding Allergic Reactions to Saxenda

Allergic reactions to Saxenda occur when the immune system mistakenly identifies the medication or its components as harmful, triggering an inflammatory response. Hives can result from immediate hypersensitivity reactions and may be mediated by immunoglobulin E (IgE) antibodies and the subsequent release of histamine and other inflammatory mediators from mast cells and basophils; however, non-IgE mechanisms can also occur. This process causes the characteristic raised, erythematous (red), and intensely pruritic (itchy) wheals that define urticaria.

The allergic response may develop at various timepoints during treatment. Some patients experience hives shortly after initiating Saxenda, whilst others may develop sensitivity after weeks or months of use. The unpredictable nature of drug hypersensitivity means that previous tolerance does not guarantee continued safety, and sensitisation can occur even after prolonged uneventful use.

Beyond isolated urticaria, patients should be aware of signs suggesting a more serious systemic allergic reaction, known as anaphylaxis. Warning features include:

• Difficulty breathing or wheezing

• Swelling of the face, lips, tongue, or throat (angioedema)

• Dizziness or feeling faint

• Rapid pulse or palpitations

• Widespread rash or hives covering large body areas

Anaphylaxis is a medical emergency requiring immediate treatment. If you experience these symptoms, call 999 immediately. If you have been prescribed an adrenaline auto-injector, use it as directed while waiting for emergency services. According to the MHRA SmPC, anaphylactic reactions have been reported with Saxenda, though they remain rare. Healthcare professionals should counsel patients about recognising these symptoms before commencing treatment.

What to Do If You Develop Hives While Taking Saxenda

If you develop hives whilst taking Saxenda, you should withhold further doses and contact your GP or prescribing clinician for urgent advice. Do not administer further doses until you have been assessed by a healthcare professional. If you cannot reach your prescriber promptly and have no red-flag symptoms, contact NHS 111 for guidance. If drug-induced hypersensitivity is suspected or confirmed, or if you develop systemic symptoms, Saxenda should be permanently discontinued.

Whilst awaiting medical review, you may find symptomatic relief through the following measures:

• Consider an oral antihistamine such as cetirizine (10mg once daily) or loratadine (10mg once daily), which are available over the counter from pharmacies. Check with a pharmacist about suitability, especially if you are pregnant, breastfeeding, or have other health conditions.

• Apply cool compresses to affected areas to soothe irritation and reduce inflammation.

• Avoid triggers that may exacerbate urticaria, including hot baths, tight clothing, alcohol, and strenuous exercise.

• Avoid scratching, as this can worsen the rash and potentially lead to skin damage or secondary infection.

Your healthcare provider will need to assess whether the hives are definitively related to Saxenda or potentially caused by other factors such as concurrent medications, foods, infections, or environmental allergens. They will review your medication history, examine the rash, and determine the appropriate management strategy. In most cases where drug-induced urticaria is confirmed or strongly suspected, the medication will be permanently discontinued.

Alternative weight management strategies should be discussed with your clinician. These may include other pharmacological options (such as orlistat), alongside dietary modification, physical activity programmes, and psychological support. If considering another GLP-1 receptor agonist, specialist allergy advice may be needed as cross-reactivity is possible but not well-established. It is essential to report this adverse reaction to the MHRA's Yellow Card Scheme (yellowcard.mhra.gov.uk), contributing to ongoing medication safety surveillance.

Other Skin Reactions Associated with Saxenda

Beyond urticaria, Saxenda is associated with several other dermatological adverse effects that patients and healthcare professionals should recognise. The most common skin-related reaction is injection site reactions, which according to the UK SmPC are classified as common (affecting between 1 in 10 and 1 in 100 patients). These typically manifest as erythema (redness), pruritus (itching), swelling, or bruising at the subcutaneous injection site. Such reactions are usually mild, transient, and resolve spontaneously without requiring treatment discontinuation.

To minimise injection site reactions, patients should:

• Rotate injection sites systematically between the abdomen, thigh, and upper arm

• Ensure the medication has reached room temperature before injecting

• Use proper injection technique as demonstrated by healthcare professionals

• Avoid injecting into areas that are tender, bruised, red, hardened, or not intact

Rash is another recognised adverse effect, reported as a common reaction (affecting between 1 in 10 and 1 in 100 patients). The rash associated with Saxenda may present in various forms, from maculopapular (flat and raised spots) to more generalised erythematous eruptions. Unlike urticaria, these rashes may not be intensely itchy and may have a different distribution pattern.

Angioedema—swelling of deeper skin layers, particularly affecting the face and throat—represents a potentially serious reaction requiring immediate medical attention due to the risk of airway compromise.

Patients should be counselled to report any new or worsening skin changes to their healthcare provider. Seek medical advice if injection-site reactions are severe, persistent, or associated with systemic symptoms. Whilst many skin reactions are benign and manageable, prompt recognition of potentially serious hypersensitivity reactions is crucial for patient safety. Healthcare professionals should maintain a low threshold for discontinuing Saxenda if significant skin reactions develop, particularly when accompanied by systemic symptoms such as fever, malaise, or mucosal involvement.

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