The NHS has urged people using a commonly prescribed medication to seek urgent medical advice if they notice any of three specific symptoms. These are linked to some of the more serious complications associated with dapagliflozin. Sold under the brand name Forxiga, dapagliflozin is mainly used to treat type 2 diabetes. It is also prescribed for people with heart failure and chronic kidney disease. While exact figures on how many prescriptions are issued each year in the UK are not publicly available, the drug is among the costliest for the health service, with NHS spending estimated at around £300 million a year in England alone.What Is Dapagliflozin?Dapagliflozin belongs to a group of medicines known as SGLT2 inhibitors. It works by helping the kidneys remove excess glucose from the body through urine, which lowers blood sugar levels. Beyond diabetes, the drug has been shown to reduce the risk of hospitalisation in people with heart failure and slow the progression of chronic kidney disease. It may be prescribed on its own or alongside other treatments, depending on a patient’s condition and overall health.Medicines That Contain DapagliflozinDapagliflozin can also be prescribed in combination with other diabetes medicines. These include Xigduo, which combines dapagliflozin with metformin, and Qtern, which pairs dapagliflozin with saxagliptin.Dapagliflozin Symptoms That Require Urgent Medical AdviceHowever, the NHS warns on its website that, “like all medicines,” dapagliflozin can cause side effects in some people. Patients are advised to “call your doctor or call 111 now” if they experience:A very dry or sticky mouth, intense thirst, feeling sleepy or unusually tired, little or no urination, and a fast heartbeat, which may be signs of dehydrationA high temperature, or feeling hot, cold or shivery, pain or burning when passing urine, pain in the back or side, or blood in the urine, which could point to a urinary tract infectionSevere pain, tenderness, redness or swelling in the groin or perineal area, along with a high temperature or feeling generally unwell, which may signal a rare but serious infection called Fournier’s gangreneDapagliflozin: How Common Are These Side Effects?These reactions are classed as rare, affecting fewer than one in 10,000 people. More common side effects occur in over one in 100 users. The NHS says: “They’re usually mild and do not last long. There are things you can do to help cope with them.”Dapagliflozin Side EffectsThe NHS lists the following as more frequent side effects:ThrushBack painPassing urine more oftenDizzinessMild skin rashesPatients are advised to speak to a doctor or pharmacist if these symptoms persist or become troublesome.Taking dapagliflozin alongside other diabetes medicines, such as insulin or sulfonylureas like gliclazide, can sometimes cause blood sugar levels to drop too low. Some people may also develop diabetic ketoacidosis (DKA).What Is Diabetic Ketoacidosis?DKA happens when the body lacks enough insulin and harmful acids, known as ketones, build up in the blood. Warning signs can include nausea or vomiting, extreme thirst, confusion or severe tiredness, stomach pain, fruity-smelling breath, and fast or deep breathing. The NHS notes that symptoms usually develop within 24 hours, though they can appear more quickly.When To Seek Emergency HelpPatients are taught how to monitor their blood sugar and ketone levels and what steps to take if symptoms appear. Emergency services should be contacted immediately by calling 999 if a person experiences a severe allergic reaction, known as anaphylaxis, after taking dapagliflozin.