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Elizabeth Hackett, principal pharmacist for diabetes, University Hospitals of Leicester, considers dapagliflozin €“ the first in a new class of diabetes medicines

Dapagliflozin (Forxiga) was launched in November 2012 and NICE has recommended that it should be available for patients on metformin as dual therapy, in a similar way as recommended for the DPP-4 inhibitors.

It may also be used with insulin, with or without other antidiabetic agents. However its use with metformin plus a sulphonlyurea is not recommended unless as part of a clinical trial.

Case study

You are an independent prescriber, seeing a 46-year-old male with type 2 diabetes. His HbA1c is 60mmol/mol (7.6 per cent) and his mutually agreed target is 48mmol/mol (6.5 per cent). He currently takes metformin 1g bd (maximum tolerated dose). He occasionally experiences hypoglycaemia but has good awareness and is able to self-treat using glucose tablets. Driving is important to him for work, so he is unwilling to take gliclazide.

He has previously taken pioglitazone and DPP-4 inhibitors but they caused unacceptable side-effects. He really does not want to self- inject and is keen to explore other oral therapies. You are considering dapagliflozin.

What baseline monitoring tests should you consider?

Baseline monitoring should include recent HbA1c (to determine efficacy of the new therapy), renal function (to check his clearance is greater than 60ml/min), blood pressure (if in any doubt that he may be at risk of hypotension), electrolytes and haematocrit (as increases have been observed in some patients starting dapagliflozin, so you will need to rule out already- elevated levels). Also liver function tests should be considered if there is any concern that they are abnormal on starting therapy.

What starting dose?

If liver function is not severely impaired, a dose of 10mg daily is a suitable starting dose.

Is he at risk from hypoglycaemia and, if so, what should he do?

Metformin and dapagliflozin are not normally associated with hypoglycaemia, so his risk would be low.

We know he has previously used glucose tablets to treat hypoglycaemia €“ he should take 5-7 tablets and be advised to consume long-acting carbohydrates (meal, slice of bread, biscuit) after successful initial treatment, with the rapid- acting carbohydrate (glucose tablets) to prevent recurrence.

What other side-effects would you counsel him on?

He should be advised that:

• Dapagliflozin has been associated with an increase in genital and urinary tract infections and that he should seek medical advice if he suspects this has happened
• He will excrete glucose in his urine and that if he undertakes urine glucose monitoring it will be positive while taking dapagliflozin 
• He may experience weight loss.