{"id":3044,"date":"2026-05-01T23:12:43","date_gmt":"2026-05-01T22:12:43","guid":{"rendered":"https:\/\/livingdiabetes.com\/diabetes-medications\/"},"modified":"2026-05-01T23:12:43","modified_gmt":"2026-05-01T22:12:43","slug":"diabetes-medications","status":"publish","type":"page","link":"https:\/\/livingdiabetes.com\/ur\/diabetes-medications\/","title":{"rendered":"Diabetes Medications: Metformin, GLP-1 Agonists, SGLT2 Inhibitors and More"},"content":{"rendered":"

Diabetes pharmacotherapy has changed more in the last decade than in the four decades before it.<\/strong> What was once a stepwise sequence \u2014 metformin, sulfonylurea, insulin \u2014 has become a personalised choice, with classes (GLP-1 receptor agonists, SGLT2 inhibitors, dual GIP\/GLP-1 agonists) chosen as much for cardiovascular and renal protection as for blood-glucose control.<\/p>\n\n\n\n

This guide explains the major classes of diabetes medication, what current NICE and ADA guidelines recommend, and what to expect from each \u2014 including side effects, monitoring, and the situations where one class is preferred over another.<\/p>\n\n\n\n

This page is educational. It does not replace personalised advice from your GP, diabetes specialist nurse, or endocrinologist. Never start, stop, or change a diabetes medication without speaking to your prescriber.<\/em><\/p>\n\n\n\n

Metformin \u2014 still first-line for most adults<\/h2>\n\n\n\n

How it works:<\/strong> Metformin reduces the amount of glucose released by the liver, modestly improves insulin sensitivity in muscle and fat, and slows intestinal glucose absorption. It does not stimulate insulin secretion, so it carries minimal hypoglycaemia risk on its own.<\/p>\n\n\n\n

When it’s used:<\/strong> NICE NG28 recommends metformin as the initial drug for most adults with newly diagnosed type 2 diabetes. Modified-release (“MR”) preparations are an option when standard metformin causes gastrointestinal side effects.<\/p>\n\n\n\n

Common side effects:<\/strong> Nausea, diarrhoea, abdominal discomfort \u2014 usually settle within a few weeks if dose is built up gradually. Long-term use can lower vitamin B12 levels, so periodic B12 testing is reasonable.<\/p>\n\n\n\n

Cautions:<\/strong> Dose should be adjusted in chronic kidney disease (eGFR 30\u201359) and avoided when eGFR is below 30. It should be temporarily stopped during acute illness with dehydration, before iodinated-contrast imaging in some scenarios, and around major surgery \u2014 your team will tell you when.<\/p>\n\n\n\n

SGLT2 inhibitors \u2014 heart and kidney protection<\/h2>\n\n\n\n

The class:<\/strong> Empagliflozin, dapagliflozin, canagliflozin, ertugliflozin. Taken as a once-daily tablet.<\/p>\n\n\n\n

How they work:<\/strong> They block glucose reabsorption in the kidney’s proximal tubule, so excess glucose is excreted in the urine. The mechanism also lowers blood pressure and produces modest weight loss.<\/p>\n\n\n\n

Why they matter:<\/strong> Large randomised cardiovascular and renal outcome trials (EMPA-REG OUTCOME, DAPA-HF, DAPA-CKD, EMPEROR-Reduced\/Preserved, CREDENCE, EMPA-KIDNEY) consistently showed reductions in heart-failure hospitalisation, progression of chronic kidney disease, and cardiovascular death. As a result, SGLT2 inhibitors are now recommended as first add-on (or even first-line, alongside metformin) when someone has established cardiovascular disease, heart failure, or chronic kidney disease \u2014 even if their HbA1c is at target.<\/p>\n\n\n\n

Common side effects:<\/strong> Genital thrush (Candida) \u2014 particularly in women and uncircumcised men \u2014 and an increase in urinary tract infections. Mild-to-moderate volume depletion in older people or those on diuretics.<\/p>\n\n\n\n

Important risk:<\/strong> Diabetic ketoacidosis (DKA) at lower-than-usual blood glucose levels (so-called “euglycaemic DKA”). The risk is higher around surgery, prolonged fasting, very low-carbohydrate diets, or acute illness. Patients should know the symptoms (nausea, vomiting, abdominal pain, fast breathing) and be told when to pause the medication.<\/p>\n\n\n\n

GLP-1 receptor agonists<\/h2>\n\n\n\n

The class:<\/strong> Semaglutide (Ozempic \u2014 weekly injection; Rybelsus \u2014 daily oral; Wegovy \u2014 weight-loss licence), dulaglutide (Trulicity), liraglutide (Victoza, Saxenda), exenatide. Most are weekly injections.<\/p>\n\n\n\n

How they work:<\/strong> They mimic the gut hormone GLP-1, which stimulates insulin release in response to food, suppresses glucagon, slows gastric emptying, and reduces appetite. The result is lower post-meal glucose and substantial weight loss in many people.<\/p>\n\n\n\n

Why they matter:<\/strong> Cardiovascular outcome trials (LEADER, SUSTAIN-6, REWIND, SELECT) have shown reductions in major adverse cardiovascular events. GLP-1 agonists are increasingly used early in type 2 diabetes management, particularly when weight loss is a treatment goal or when cardiovascular risk is high.<\/p>\n\n\n\n

Common side effects:<\/strong> Nausea, vomiting, constipation or diarrhoea \u2014 usually worst when starting and after each dose increase, and usually improves with time. Injection-site reactions are mild.<\/p>\n\n\n\n

Important considerations:<\/strong> The substantial weight loss is partly fat and partly lean mass, so resistance training and adequate protein intake are important to preserve muscle. There is a class warning relating to medullary thyroid cancer in animal studies; the human signal is uncertain but the drugs are avoided in people with personal or family history of medullary thyroid carcinoma or MEN2. Acute pancreatitis is uncommon but recognised.<\/p>\n\n\n\n

Dual GIP\/GLP-1 agonists \u2014 tirzepatide<\/h2>\n\n\n\n

What it is:<\/strong> Tirzepatide (Mounjaro) acts on both GLP-1 and GIP receptors. The SURPASS programme in type 2 diabetes and SURMOUNT programme in obesity showed greater HbA1c and weight reductions than semaglutide head-to-head. SURMOUNT-1 demonstrated average weight loss of approximately 21% at the highest dose.<\/p>\n\n\n\n

Side-effect profile is similar to GLP-1 agonists. Long-term cardiovascular outcome data are still maturing.<\/p>\n\n\n\n

DPP-4 inhibitors<\/h2>\n\n\n\n

The class:<\/strong> Sitagliptin, linagliptin, alogliptin, saxagliptin, vildagliptin. Daily tablets.<\/p>\n\n\n\n

They prolong the action of native GLP-1 by blocking the enzyme that breaks it down. They are weight-neutral and well-tolerated, with minimal hypoglycaemia risk. Glycaemic effect is modest. They are not associated with cardiovascular protection beyond glucose lowering, so they are typically chosen when GLP-1 agonists or SGLT2 inhibitors are unsuitable.<\/p>\n\n\n\n

Sulfonylureas<\/h2>\n\n\n\n

The class:<\/strong> Gliclazide is the most commonly used in the UK; glimepiride and glipizide elsewhere.<\/p>\n\n\n\n

Sulfonylureas stimulate insulin release from the pancreas. They are inexpensive and effective at lowering glucose, but they cause weight gain and carry meaningful hypoglycaemia risk \u2014 particularly in older adults, people with chronic kidney disease, or those who skip meals. They are no longer used as a first add-on in most NICE pathways but still have a role when cost or specific tolerability concerns make newer drugs unsuitable.<\/p>\n\n\n\n

Pioglitazone<\/h2>\n\n\n\n

A thiazolidinedione that improves insulin sensitivity. Effective at lowering HbA1c and may help non-alcoholic fatty liver disease, but causes weight gain, fluid retention (avoid in heart failure), and an increased fracture risk. Bladder cancer signal has been reported in some studies and remains a topic of debate. Less commonly used today, but still helpful in selected patients with insulin resistance and fatty liver.<\/p>\n\n\n\n

Insulin<\/h2>\n\n\n\n

When it’s used:<\/strong> Always in type 1 diabetes. In type 2 diabetes, insulin is added when oral and non-insulin injectable therapies are no longer enough. In gestational diabetes, insulin (often with metformin) is the standard when diet alone doesn’t keep glucose in target range.<\/p>\n\n\n\n

Major regimens:<\/strong><\/p>\n\n\n\n