Forxiga (Dapagliflozin)

Dapagliflozin (brand name Forxiga, Farxiga in the US) is a selective inhibitor of sodium-glucose cotransporter 2, SGLT2 for short. It was the first agent of its class with broad approval in Europe and is today approved for type 2 diabetes, heart failure and chronic kidney disease.

The approach is unusual because it bypasses the pancreas entirely. Instead of raising insulin or improving insulin action, dapagliflozin simply lets sugar drain out through the urine. That makes it insulin-independent and explains why it barely causes hypoglycemia in monotherapy.

This information is for research and educational purposes only. No medical advice.

The kidney filters a substantial amount of glucose every day. To stop it being lost, the SGLT2 transporter in the proximal tubule pulls roughly 90 percent of it back into the blood. Dapagliflozin blocks exactly that transporter, with more than 1000-fold selectivity over intestinal SGLT1 - which is why dietary glucose uptake stays untouched.

What remains is a targeted glucosuria. At 10mg daily, studies document roughly 70 grams of glucose excreted renally per day, equivalent to about 280 kilocalories. The excreted sugar drags water with it osmotically, which explains the mild diuresis and slight blood pressure drop. In parallel, hematocrit and hemoglobin rise measurably.

• Bioavailability: about 78 percent absolute, oral.
• Onset: peak concentration after roughly 1 to 2 hours fasted. Food delays the peak but does not meaningfully change total absorption.
• Half-life: about 12.9 hours after a single 10mg dose - supports once-daily dosing.
• Clearance: mainly via UGT1A9 to the inactive dapagliflozin 3-O-glucuronide, not primarily via CYP450. The interaction profile is comparatively lean as a result.
• Excretion: predominantly renal, a smaller share via faeces.

This is the most important rare danger of the whole SGLT2 class and the reason this substance is not a free lunch. In classic ketoacidosis blood glucose shoots up and you notice. Under SGLT2 inhibition the sugar is continuously dumped through the urine - ketones rise anyway while blood glucose stays normal or only mildly elevated. A glucose meter simply shows nothing.

In DECLARE-TIMI 58 diabetic ketoacidosis occurred in 0.3 percent on dapagliflozin versus 0.1 percent on placebo. The case series by Peters et al. describes the pattern systematically. Triggers described in the literature:

• Ketogenic or strongly carbohydrate-restricted eating.
• Extended fasting or an aggressive calorie deficit.
• Alcohol.
• Infections, surgery, dehydration.

That exact constellation is everyday life in the fitness scene, which makes the risk practical rather than theoretical. Anyone researching on low carb measures ketones instead of glucose. Nausea, vomiting, abdominal pain, unusually deep breathing or confusion are described in the literature as warning signs and belong in medical hands.

DAPA-HF (McMurray et al., NEJM 2019) studied roughly 4700 participants with heart failure and reduced ejection fraction. 10mg daily lowered the primary composite of worsening heart failure and cardiovascular death by about a quarter - in participants with and without diabetes. That was the finding that pulled the class out of the pure diabetes corner.

DECLARE-TIMI 58 (Wiviott et al., NEJM 2019) is the large safety and endpoint trial with over 17,000 participants and roughly 4 years of follow-up. The classic MACE endpoint was not significantly reduced, while the composite of cardiovascular death and heart failure hospitalization clearly was. The same trial supplies the solid figures on ketoacidosis and genital infections.

DAPA-CKD (Heerspink et al., NEJM 2020) and DELIVER (Solomon et al., NEJM 2022) extended the picture to chronic kidney disease and to heart failure with preserved ejection fraction respectively.

• Genital fungal infections: most common documented effect, a direct consequence of glucose in the urine. Women affected considerably more often.
• Urinary tract infections: also documented above placebo level.
• Volume depletion: dizziness, orthostatic complaints, dehydration. Amplified by diuretics, heat, training or low fluid intake.
• Euglycemic ketoacidosis: rare but serious. See the dedicated section above.
• Fournier gangrene: very rare necrotising infection of the genital and perineal area, a safety signal across the whole class.
• Initial eGFR dip: reversible drop in the first weeks, then a slower decline than under placebo.
• Hematocrit increase: measurable. Relevant when blood values already sit high.
• Hypoglycemia: low in monotherapy, clearly more frequent combined with insulin or sulfonylureas.

Store dry, protected from light, at room temperature. Keep tablets in the original bottle. Out of reach of children.