What are the necessary tests and monitoring for side effects when taking Dapagliflozin (SGLT2 inhibitor)?

Monitoring and Testing for Dapagliflozin Side Effects

Before starting dapagliflozin, assess renal function (eGFR), volume status, and correct any volume depletion; monitor renal function periodically thereafter as clinically indicated. 1

Pre-Initiation Testing

Baseline assessments required before starting dapagliflozin:

• Renal function (eGFR/creatinine) - Required to determine appropriate dosing and contraindications 1
• Volume status assessment - Particularly critical in elderly patients, those with renal impairment (eGFR <60 mL/min/1.73 m²), low systolic blood pressure, or patients on diuretics 1
• Electrolytes (potassium) - Baseline measurement recommended, especially if on other medications affecting potassium 2
• Blood pressure - Document baseline, especially if systolic BP <100 mmHg 2

Ongoing Monitoring During Treatment

Renal Function Monitoring

• Monitor eGFR periodically as clinically indicated after initiation 1
• Expect an initial eGFR decline of 3-5 mL/min/1.73 m² within the first 4 weeks - this is typically reversible and not an indication to discontinue therapy 3
• More frequent monitoring needed in patients with baseline eGFR 30-60 mL/min/1.73 m² or those at risk for acute kidney injury 2, 1
• Consider temporarily discontinuing in settings of reduced oral intake, fluid losses, or acute illness that may impair renal function 2, 1

Volume Status and Blood Pressure

• Monitor for signs and symptoms of volume depletion throughout therapy, including dizziness, lightheadedness, orthostatic hypotension, and syncope 1
• Higher risk populations requiring closer monitoring: elderly patients (≥65 years), those with eGFR <60 mL/min/1.73 m², patients on diuretics, and those with low baseline blood pressure 2, 1
• Consider reducing diuretic doses in patients at risk for hypovolemia or hypotension 2, 3

Infection Surveillance

Genital mycotic infections:

• Counsel patients on proper genital hygiene before and during therapy 4
• Monitor for symptoms at each visit: vaginal odor, discharge, itching in females; penile redness, rash, or swelling in males 1
• Incidence approximately 6% with SGLT2 inhibitors versus 1% with placebo 4
• Most infections are mild to moderate and respond to standard antifungal therapy without requiring drug discontinuation 4, 5

Urinary tract infections:

• Evaluate for signs and symptoms of UTIs and treat promptly if indicated 1
• Dapagliflozin 10 mg specifically has been associated with increased UTI risk compared to placebo (RR 1.33) 6, 7
• Higher vigilance needed in patients with bladder outlet obstruction or urinary retention 8
• Watch for progression to serious infections: urosepsis and pyelonephritis require prompt evaluation and treatment 1

Fournier's gangrene (necrotizing fasciitis of the perineum):

• Assess patients presenting with: pain or tenderness, erythema, or swelling in the genital or perineal area, along with fever or malaise 2, 1
• This is a rare but life-threatening complication requiring immediate discontinuation and urgent surgical/antibiotic management 2, 4

Ketoacidosis Monitoring

Diabetic ketoacidosis (DKA) can occur even with normal or mildly elevated blood glucose (euglycemic DKA):

• Implement "STOP DKA" protocol education: Stop SGLT2 inhibitor, Test for ketones, maintain fluid and carbohydrate intake 9
• Consider ketone monitoring in high-risk patients: those with type 1 diabetes, pancreatic insufficiency, insulin-requiring type 2 diabetes, or during acute illness 1
• Assess for ketoacidosis if patients present with: nausea, vomiting, abdominal pain, tiredness, or trouble breathing - regardless of blood glucose level 1
• Hold dapagliflozin during acute illness (nausea, vomiting, diarrhea), prolonged fasting, or surgery 2, 9
• Withhold for at least 3 days prior to major surgery or procedures with prolonged fasting 1

Hypoglycemia Monitoring

• Monitor blood glucose more frequently when dapagliflozin is combined with insulin or insulin secretagogues (sulfonylureas) 1
• Consider dose reduction of insulin or insulin secretagogue when initiating dapagliflozin to reduce hypoglycemia risk 1
• Educate patients on signs and symptoms of hypoglycemia 1

Special Population Considerations

Elderly patients (≥65 years):

• Higher incidence of adverse reactions related to hypotension and volume depletion 1
• More frequent monitoring of volume status and blood pressure needed 1

Patients with renal impairment:

• Higher incidence of volume depletion-related adverse reactions 1
• Reduced glycemic efficacy when eGFR <45 mL/min/1.73 m², though cardiorenal benefits persist 2, 3
• Close monitoring of renal function and volume status essential 3

Immunocompromised patients:

• May be at higher risk for infections and require more careful monitoring 4

Laboratory Testing Summary

No routine laboratory monitoring is specifically required beyond:

• Periodic renal function (eGFR/creatinine) assessment 1
• Electrolytes as clinically indicated 2
• Blood glucose monitoring (especially if on insulin or secretagogues) 1
• Ketone testing if DKA suspected or in high-risk patients 1

Note: Patients taking dapagliflozin will test positive for glucose in their urine due to the drug's mechanism of action - this is expected and not a cause for concern 1

Common Pitfalls to Avoid

• Do not discontinue dapagliflozin for the initial expected eGFR decline of 3-5 mL/min/1.73 m² in the first 4 weeks 3
• Do not confuse euglycemic ketoacidosis symptoms with other conditions - always check ketones if metabolic acidosis symptoms present, even with normal glucose 9, 3
• Do not continue dapagliflozin during acute illness with reduced oral intake - implement sick day rules 9, 1
• Do not overlook Fournier's gangrene - any genital/perineal pain with fever requires immediate evaluation 2, 4
• Most genital mycotic infections do not require drug discontinuation - treat with standard antifungals and continue dapagliflozin 4