Drug Detail:Farxiga (Dapagliflozin)
Drug Class: SGLT-2 inhibitors
1. How it works
- Farxiga is a brand (trade) name for dapagliflozin which may be used in the treatment of type 2 diabetes, heart failure, and chronic kidney disease.
- Dapagliflozin works by blocking the sodium-glucose co-transporter 2 (SGLT2) which is a protein located in the early proximal tubule of a nephron (a kidney cell), which is responsible for the reabsorption of glucose from the blood that flows through the kidneys (the glomerular filtrate) back into circulation. By blocking this transporter, dapagliflozin prevents glucose from being reabsorbed and increases how much glucose is excreted in the urine. This helps to lower blood sugar and improve A1C. Dapagliflozin also reduces sodium reabsorption and increases the delivery of sodium to the distal tubule, which can help reduce loading on the heart and how hard it has to work to pump blood around the body.
- Farxiga belongs to the class of medicines called SGLT-2 inhibitors.
2. Upsides
- May be used in the treatment of type 2 diabetes alongside diet modification and increased exercise. Can reduce the risk of hospitalization for heart failure in adults with type 2 diabetes mellitus with established cardiovascular disease or multiple cardiovascular risk factors.
- Farxiga may be used to reduce the risk of sustained eGFR decline, end stage kidney disease, cardiovascular death, and hospitalization for heart failure in adults with chronic kidney disease at risk of progression.
- May also be used in adults with heart failure to reduce the risk of cardiovascular death, hospitalization for heart failure, or urgent heart failure visits.
- Effective at reducing blood glucose levels, HbA1c, and it also reduces body weight.
- May be given in addition to other medications for diabetes, such as insulin, metformin, or sulfonylureas; however, the dosage of these medications may need reducing as there is an increased risk of hypoglycemia with combination treatment.
- No dosage adjustment is needed in people with an eGFR of greater than 45 mL/min/1.73m2.
- No dosage adjustment is needed in people with liver disease; however, Farxiga has not been studied extensively in patients with severe liver disease.
- Most people taking Farxiga lose around 2.6 to 2.7 kg of weight. However, some may gain weight.
- Farxiga is taken orally.
3. Downsides
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- Common side effects of Farxiga include low blood sugar levels, low blood pressure (especially when starting Farxiga), genital and urinary tract infections, a congested nose, back pain, increased urination, nausea, and high cholesterol.
- An increased risk of bone fracture has also been observed in patients with mild-to-moderate kidney disease.
- Farxiga is not suitable for people with type 1 diabetes or to treat diabetic ketoacidosis.
- Farxiga causes an increase in urination which can lead to dehydration or a drop in blood pressure. Any dehydration or volume depletion should be corrected before starting Farxiga. Those with volume depletion, seniors with kidney disease, or who are also taking diuretics, are more at risk.
- Contraindicated in those with an eGFR less than 30 mL/min/1.73m2 being treated for glycemic control without established CV disease or multiple CV risk factors. People with an eGFR of 30-60 mL/min/1.73m2 are more likely to experience low blood pressure, bone fractures, and acute kidney injury. The risk may be exacerbated in those who are dehydrated, taking certain medications, such as NSAIDs, ACE inhibitors, ARBs, or diuretics, or in those with a reduced calorie intake. However, recent studies have shown Farxiga to be effective at reducing the risk of renal functioning worsening, end-stage kidney disease, and cardiovascular or renal death when given to people with CKD.
- Not recommended for the treatment of CKD caused by polycystic kidney disease or in people with a history of immunosuppressive therapy for kidney disease, because it is not expected to be effective in these populations.
- Farxiga has been associated with an increased risk of diabetic ketoacidosis (caused by a severe lack of insulin), which may be life-threatening. This may be associated with severe metabolic acidosis. If this occurs, prompt treatment for ketoacidosis should be initiated and Farxiga discontinued. Those with pancreatic insulin deficiency, on a calorie-restricted diet, or with an excessive alcohol intake are more at risk. Note that presenting blood glucose levels were below those typically seen with diabetic ketoacidosis (often less than 250 mg/dL).
- Treatment with Farxiga increases the risk of urinary tract infections, genital fungal infections, and a rare necrotizing infection called necrotizing fasciitis of the perineum (Fournier's gangrene), which causes pain, tenderness, redness, and swelling in the genital area.
- LDL cholesterol levels may increase with Farxiga treatment.
- Farxiga is not recommended during the second and third trimester of pregnancy and there is a lack of data assessing the risk for the first trimester of pregnancy. However, the risk of Farxiga use in the first trimester should be weighed up against the risk of uncontrolled diabetes on the fetus with regards to birth defects and miscarriage.
Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects
4. Tips
- Farxiga is usually taken once daily in the morning, with or without food. Your doctor will start you on 5mg and may increase the dose to 10mg if you need additional blood sugar control, are tolerating Farxiga well, and do not have kidney disease.
- Tell your doctor before you start Farxiga if you have a history of heart disease, poor circulation or nerve damage, liver problems, urinary problems, planning to have surgery, or are on a low sodium diet.
- Take Farxiga exactly as prescribed. If you miss a dose, take it as soon as you remember but not if it is within eight hours of your next dose, just go back to your regular dosing schedule.
- Farxiga should be taken in addition to any other medications prescribed by your doctor. You should also adhere to any dietary recommendations and undertake regular physical activity. See your doctor if you develop any kind of infection, are scheduled for surgery, or are dealing with a lot of stress as your medication requirements may change.
- Farxiga may cause your blood pressure to drop. This is more likely when you first start taking Farxiga, in seniors, in people already with low blood pressure, in those taking a low sodium diet, and in those taking diuretics. This may make you feel dizzy or faint. Talk to your doctor if this happens.
- Tell your doctor immediately if you develop signs or symptoms of diabetic ketoacidosis which may include excessive thirst, frequent urination, abdominal pain, fruity breath, or severe metabolic acidosis which may include nausea and vomiting, shortness of breath, or fatigue. Educate your friends and family about the signs of diabetic ketoacidosis and metabolic acidosis to watch out for.
- Farxiga has been associated with an increased risk of urinary tract infections. If you develop symptoms such as burning or pain when urinating, an increased frequency of urination, fever, back or pelvic pain, see your doctor.
- Farxiga may also increase your risk of genital infections. Symptoms of a vaginal yeast infection include a white or yellowish vaginal discharge, vaginal itching, or vaginal odor. Symptoms of a yeast infection of the penis include redness, itching, swelling of the penis, a foul-smelling discharge, or penile pain.
- If you are intending to become pregnant while taking Farxiga, talk to your doctor before you conceive.
5. Response and effectiveness
- Farxiga causes an increase in the excretion of glucose in the urine very soon after the initial dose. In trials, dapagliflozin doses of 5mg or 10mg per day resulted in an average of 70 grams of glucose per day being excreted in the urine in patients with type 2 diabetes after 12 weeks of treatment.
- The maximum concentration of Farxiga occurs within two hours of a dose. Although food can decrease the peak concentration of Farxiga, and prolong the time it takes to reach maximum concentrations, these changes are not considered to be clinically meaningful and Farxiga can be administered with or without food.
- After 24 weeks of treatment, the average decrease in HbA1C from baseline for Farxiga 5mg was 0.8 and Farxiga 10mg was 0.9. The decrease in fasting plasma glucose from baseline was 24.1 for Farxiga 5mg and 28.8 for Farxiga 10mg. Combination treatment typically improved response.
- In DAPA-CKD Phase III trial, which was conducted in people with chronic kidney disease, Farxiga significantly reduced the risk of the composite of worsening of renal function, end-stage kidney disease, and cardiovascular or renal death by approximately 39%.
6. Interactions
Medicines that interact with Farxiga may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Farxiga. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.
Common medications that may interact with Farxiga include:
- acetazolamide
- anticonvulsants such as phenytoin or phenobarbital
- antipsychotics, such as aripiprazole or clozapine
- ARBs such as valsartan
- beta-blockers, such as atenolol, labetalol, and metoprolol, may enhance the hypoglycemic effects
- ciprofloxacin or gatifloxacin
- corticosteroids, such as prednisone or cortisone
- digoxin
- diuretics, such as bumetanide, HCTZ, and bendroflumethiazide, which may enhance the potential for volume depletion
- HIV medications, such as amprenavir, atazanavir, fosamprenavir, and ritonavir
- hormones, such as ethinylestradiol and hydroxyprogesterone
- insulin (may increase risk of hypoglycemia)
- isoniazid
- NSAIDs, such as mefenamic acid
- rifampin
- other medications that affect blood sugar levels or are used for diabetes, such as glimepiride, or metformin.
Farxiga may also enhance the toxic effects of alcohol, causing flushing. Alcohol may also increase the risk of hypoglycemia and diabetic ketoacidosis.
Urine glucose tests should not be used to monitor glucose control in people receiving SGLT2 inhibitors such as Farxiga as these increase urinary glucose excretion and will lead to positive urine glucose tests. Alternative methods to monitor glucose control should be used. Interference with 1,5-AG assays may also occur.
Note that this list is not all-inclusive and includes only common medications that may interact with Farxiga. You should refer to the prescribing information for Farxiga for a complete list of interactions.