Dapagliflozin (Forxiga): uses, side effects and cautions

The NHS says dapagliflozin treats type 2 diabetes, heart failure and chronic kidney disease. The emc SmPC for Forxiga confirms these three adult uses and adds that it can be used in children aged ten and over for type 2 diabetes. It blocks SGLT2 transporters in the kidney tubules so less glucose is taken back into the blood.

The NHS also notes a benefit for the heart: it can reduce the amount of work the heart needs to do to pump blood around the body, because of the mild water-losing effect it has.

One tablet once a day, ideally at the same time, with or without food. Treatment is usually long term. The SmPC gives 10 mg once daily as the standard dose, with a lower starting strength for severe liver disease. Glucose-lowering effect is smaller when kidney function is reduced, and it is not recommended to start it below a stated kidney threshold. Kidney function and blood pressure are monitored.

If you miss a dose and fewer than 12 hours remain until the next one, the NHS says to skip the missed tablet.

The NHS lists fungal infections, back pain, increased urination and low blood sugar with dizziness. The SmPC rates genital infections (vulvovaginitis, balanitis) as very common, and urinary tract infection, volume depletion, dizziness, back pain and passing more urine as common. Uncommon effects include thirst, constipation, dry mouth, nocturia, pain on passing urine, genital itch, rash and weight loss.

Most genital infections are mild to moderate and respond to standard treatment. Keeping the genital area clean and dry and seeking early advice helps.

Rare but serious effects include allergic reactions, diabetic ketoacidosis (breath that smells sweet is one sign), severe urinary infection and Fournier's gangrene, a necrotising infection of the genital or perineal area. The SmPC stresses that ketoacidosis may occur with only moderately raised glucose, and that treatment is paused during hospital admission for major surgery or acute serious illness. The NHS says to call NHS 111 for serious effects.

• Seek urgent help for genital or perineal pain, redness or swelling with fever.

• Seek urgent help for nausea, vomiting, stomach pain, rapid breathing or sweet-smelling breath.

The NHS lists type 1 diabetes, liver problems, allergy to dapagliflozin, and frequent urinary infections as reasons it may be unsuitable, and mentions caution with blood pressure-lowering medicines. Older people and anyone prone to dehydration need extra care. The SmPC asks for foot care counselling after amputation reports with this drug class.

The NHS names furosemide and other diuretics, gliclazide and other diabetes medicines, blood pressure medicines and lithium. The SmPC explains that dapagliflozin may increase lithium excretion, so lithium levels are checked more often, and that mefenamic acid raises its exposure without needing a dose change. Alcohol can lower blood pressure, so the NHS advises limiting it. Do not drive if dizzy.

The SmPC says use is not recommended in the second and third trimesters because of animal kidney findings, and it should not be used while breastfeeding. It is prescription only. Report suspected side effects to the Yellow Card scheme.