Semaglutide

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist used in the management of type 2 diabetes mellitus and, in specific formulations and jurisdictions, chronic weight management and reduction of certain cardiovascular or kidney-related risks. It mimics the activity of the naturally occurring GLP-1 hormone, helping the body release insulin when blood glucose levels are elevated, reducing glucagon secretion in a glucose-dependent manner, slowing gastric emptying to varying degrees, and regulating appetite and food intake. These effects can improve blood glucose control and support weight reduction when treatment is combined with appropriate dietary and lifestyle measures. Semaglutide is available as a once-weekly subcutaneous injection and as an oral tablet in approved formulations; the indications, doses and administration instructions differ by product and country. It is not interchangeable dose-for-dose across formulations, and products containing semaglutide should not generally be combined with one another or with other GLP-1 receptor agonists. Common adverse effects include nausea, vomiting, diarrhoea, constipation and abdominal discomfort. Important safety considerations include dehydration-related kidney injury, gallbladder disease, pancreatitis, hypoglycaemia when used with certain diabetes medicines, and specific thyroid-tumour precautions in jurisdictions where these appear in the product label. Treatment requires individual assessment and ongoing clinical monitoring.

Semaglutide was developed as a long-acting GLP-1 receptor agonist for metabolic disease management. The US Food and Drug Administration (FDA) first approved injectable semaglutide for type 2 diabetes in 2017. The European Commission authorised the injectable product Ozempic in 2018, while the oral formulation Rybelsus received European Union authorisation in 2020. The FDA approved oral semaglutide for type 2 diabetes in 2019. A higher-dose injectable formulation for chronic weight management was authorised in the United States in 2021 and in the European Union in January 2022. Additional indications have since been approved for particular products, including cardiovascular risk reduction and, for selected patients with type 2 diabetes, kidney-related outcomes. In India, the Central Drugs Standard Control Organisation (CDSCO) has recorded approvals for semaglutide formulations and indications; the approved uses and availability should be checked against the current Indian product information.

The clinical evidence base includes the SUSTAIN programme, which evaluated injectable semaglutide in type 2 diabetes; the PIONEER programme, which studied oral semaglutide; the STEP programme, which assessed weight management; the SELECT trial, which investigated cardiovascular outcomes in people with overweight or obesity and established cardiovascular disease without diabetes; and the FLOW trial, which evaluated kidney and cardiovascular outcomes in people with type 2 diabetes and chronic kidney disease. Regulatory approval and labelled indications differ by formulation, population and country, so results from one product or trial should not automatically be applied to every semaglutide formulation.

Semaglutide is used to improve glycaemic control in adults with type 2 diabetes mellitus, alongside diet and physical activity. Depending on the approved product label, it may be used alone when other medicines are unsuitable or in combination with other glucose-lowering treatments. Certain injectable formulations are also indicated for reducing major cardiovascular events in defined high-risk populations, and specific product labels include reducing the risk of sustained kidney function decline, end-stage kidney disease or cardiovascular death in eligible patients with type 2 diabetes and chronic kidney disease.

For chronic weight management, approved semaglutide formulations may be prescribed with a reduced-calorie diet and increased physical activity to support weight loss and maintenance in adults with obesity, or in adults who are overweight and have at least one weight-related medical condition. Some jurisdictions also authorise particular formulations for selected adolescents with obesity. Eligibility criteria and age limits vary by label.

Semaglutide is not indicated for every person who wishes to lose weight and is not a substitute for a comprehensive diabetes or obesity management plan. It is not intended to treat type 1 diabetes or diabetic ketoacidosis. The clinician should confirm the specific product’s current approved indication and assess the patient’s medical history, treatment goals and concurrent medicines before prescribing.

Semaglutide dosing depends on the formulation, indication, response to treatment, tolerability and applicable local prescribing information. Injectable formulations are generally administered subcutaneously once weekly, commonly in the abdomen, thigh or upper arm, with gradual dose escalation to reduce gastrointestinal adverse effects. For one widely used diabetes injection regimen, treatment begins at 0.25 mg once weekly for four weeks before increasing to 0.5 mg once weekly; further increases may be considered at the intervals and dose levels specified in that product’s label. The initial dose is used for treatment initiation and is not intended to provide full glycaemic control.

Oral semaglutide is taken once daily according to the specific product instructions, typically on an empty stomach with a small amount of plain water, followed by a required waiting period before food, beverages or other oral medicines. The exact tablet strengths and instructions depend on the approved formulation and country. Oral and injectable doses are not interchangeable milligram-for-milligram.

Patients should follow the prescribed schedule and product-specific instructions for missed doses, storage, injection technique and dose escalation. They should not increase the dose independently, use multiple semaglutide products together, or combine semaglutide with another GLP-1 receptor agonist unless explicitly directed by the treating specialist in accordance with applicable guidance.

The most frequently reported adverse effects are gastrointestinal and include nausea, vomiting, diarrhoea, constipation, abdominal discomfort and reduced appetite. These effects are often more noticeable when treatment begins or after a dose increase and may improve as the body adjusts. Some patients experience indigestion, bloating, belching, fatigue or injection-site reactions. Reduced food and fluid intake can contribute to dehydration, particularly when vomiting or diarrhoea is persistent.

Gradual dose escalation, eating smaller meals and avoiding foods that aggravate symptoms may improve tolerability, but persistent or severe symptoms require clinical assessment. Patients should not stop or change treatment without discussing the decision with their healthcare professional, except when urgent medical advice is required for a suspected serious reaction.

Semaglutide has several important safety considerations. Product labels in some jurisdictions include a boxed warning concerning thyroid C-cell tumours observed in rodents; the relevance of this finding to humans is uncertain. Under US labelling, semaglutide products carrying this warning are contraindicated in people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2. The applicable local product information should be consulted.

Acute pancreatitis has been reported with GLP-1 receptor agonists, including semaglutide. Persistent, severe abdominal pain, particularly if it radiates to the back or occurs with vomiting, requires urgent medical evaluation. Gallstones and gallbladder inflammation may also occur. Severe gastrointestinal reactions can lead to dehydration and acute kidney injury, especially in patients who cannot maintain adequate fluid intake. Semaglutide may increase the risk of hypoglycaemia when used with insulin or sulfonylureas, and dose adjustment of those medicines may be necessary.

Rapid improvement in blood glucose control may be associated with worsening diabetic retinopathy in some patients, particularly those with pre-existing disease. Severe allergic reactions have also been reported. Because semaglutide delays gastric emptying, aspiration has been reported during general anaesthesia or deep sedation; patients should inform their procedural and anaesthesia teams that they are receiving treatment. New or severe symptoms should be assessed promptly by a healthcare professional.

Before starting semaglutide, clinicians should assess the patient’s diabetes status, weight-related health risks, kidney function where clinically indicated, gastrointestinal history, gallbladder or pancreatic history, diabetic retinopathy status and concurrent medicines. Use in pregnancy requires particular consideration: semaglutide should not be used for weight reduction during pregnancy, and product-specific instructions should be followed when planning pregnancy. For US-labelled injectable semaglutide, discontinuation at least two months before a planned pregnancy is recommended because of its prolonged persistence in the body.

Semaglutide delays gastric emptying and may affect the absorption of some oral medicines. Particular care is warranted with medicines requiring close monitoring or precise timing. Concurrent insulin or sulfonylurea treatment can increase the risk of hypoglycaemia. Combining semaglutide with another semaglutide-containing product or another GLP-1 receptor agonist is generally not recommended.

Caution is appropriate in patients with severe gastrointestinal disease, including severe gastroparesis, and in those at risk of dehydration. Patients with a history of diabetic retinopathy may require closer eye monitoring when glucose control improves rapidly. The prescriber should review all medicines, supplements, relevant medical conditions and planned procedures before and during treatment. Product-specific prescribing information should guide decisions because contraindications and warnings can differ between jurisdictions and formulations.

Confirm the intended indication and verify that the selected semaglutide product is approved for that use in the relevant country. Do not assume that a diabetes formulation and a weight-management formulation have the same dose schedule, device, tablet instructions or approved patient population. Explain the planned dose escalation and expected gastrointestinal effects before treatment begins.

For injectable products, demonstrate the correct injection technique, site rotation, pen handling and storage requirements. For oral products, explain the exact fasting, water-volume and waiting-period instructions in the package leaflet. Check the patient’s other glucose-lowering medicines and consider whether insulin or sulfonylurea doses need adjustment to reduce hypoglycaemia risk.

Review glycaemic response, body weight where relevant, tolerability, hydration and adherence at follow-up. Monitor kidney function when clinically indicated, particularly after persistent vomiting or diarrhoea, and assess retinopathy risk in patients with diabetes. Counsel patients to seek prompt assessment for severe persistent abdominal pain, symptoms of gallbladder disease, allergic reactions, significant visual changes or inability to maintain fluid intake. Before surgery or deep sedation, ensure that the patient informs the procedural team about semaglutide because delayed gastric emptying may affect aspiration risk management. Document treatment goals and reassess whether ongoing therapy remains appropriate.