What telmisartan dose and monitoring plan should be used in a patient with impaired renal function (estimated glomerular filtration rate 30–60 mL/min/1.73 m², <30 mL/min/1.73 m², or on dialysis)?

Telmisartan Dosing in Renal Impairment

No Dose Adjustment Required

Telmisartan does not require dose adjustment in patients with impaired renal function, including those with eGFR 30-60 mL/min/1.73 m², <30 mL/min/1.73 m², or on dialysis. 1

Rationale for No Adjustment

• The FDA label explicitly states: "No dosage adjustment is necessary in patients with decreased renal function" 1
• Telmisartan is eliminated >97% unchanged in feces via biliary excretion, with only 0.49-0.91% excreted in urine 1
• Telmisartan is not removed by hemofiltration or hemodialysis 1, 2
• Clinical studies in severe renal insufficiency (including dialysis patients) showed telmisartan was well tolerated with no clinically relevant changes in vital signs 2

Standard Dosing Across All Renal Function Levels

• Initial dose: 40 mg once daily 3, 4, 5
• Titration: Increase to 80 mg once daily after 4 weeks if blood pressure remains uncontrolled (DBP ≥90 mmHg or SBP ≥140 mmHg) 3, 4, 5
• Maximum dose: 80 mg once daily 4, 5

This dosing applies uniformly whether eGFR is >60,30-60, <30 mL/min/1.73 m², or patient is on hemodialysis 1, 5

Critical Monitoring Requirements

Electrolytes and Renal Function

• Baseline: Measure serum creatinine, potassium, and eGFR before initiation 6
• Early monitoring: Recheck potassium and creatinine within 2-3 days, then at 7 days after initiation 6
• Ongoing monitoring: Monthly for first 3 months, then every 3 months thereafter 6
• Trigger for increased monitoring: Any addition or dose increase of other RAAS inhibitors (ACE inhibitors, ARBs, aldosterone antagonists) should restart the monitoring cycle 6

Contraindications Based on Laboratory Values

• Do not initiate if serum creatinine >2.5 mg/dL in men or >2.0 mg/dL in women (eGFR <30 mL/min/1.73 m²) AND potassium >5.0 mEq/L 6
• Do not initiate if potassium >5.0 mEq/L at baseline 6

Common Pitfalls and How to Avoid Them

Hyperkalemia Risk

• Discontinue potassium supplements when initiating telmisartan 6
• Counsel patients to avoid high-potassium foods and NSAIDs 6
• Avoid triple RAAS blockade: Do not combine telmisartan with both ACE inhibitor and aldosterone antagonist 6
• Hold medication during episodes of diarrhea or dehydration 6

Acute Kidney Injury Prevention

• Monitor for volume depletion: Patients on diuretics or with diarrhea/vomiting are at higher risk 1
• Avoid NSAIDs: Co-administration with NSAIDs (including COX-2 inhibitors) can cause acute renal failure, especially in elderly or volume-depleted patients 1
• Monitor renal function periodically when telmisartan is combined with NSAIDs 1

Drug Interactions Requiring Monitoring

• Digoxin: Monitor digoxin levels when initiating, adjusting, or discontinuing telmisartan (increases digoxin peak concentration by 49% and trough by 20%) 1
• Lithium: Monitor serum lithium levels during concomitant use due to risk of toxicity 1
• Aliskiren: Do not co-administer with telmisartan in diabetic patients; avoid in patients with eGFR <60 mL/min/1.73 m² 1

Clinical Evidence Supporting Safety in Renal Impairment

• Studies in patients with CrCl 30-80 mL/min showed mean CrCl decrease of only 4.6% with telmisartan, which was not clinically significant 3
• In patients with moderate to severe CKD (including hemodialysis), telmisartan effectively reduced blood pressure without worsening renal function 4, 5
• Telmisartan reduced proteinuria significantly (2.37 vs 1.27 g/24 hours, p<0.05) in CKD patients after 1 year of treatment 4
• Only 9.4% of patients showed decrease in 24-hour urine creatinine at end of treatment, with only 3 patients discontinuing due to renal concerns 5

Special Populations

Hemodialysis Patients

• No timing adjustment needed: Telmisartan can be administered at any time relative to dialysis session since it is not removed by dialysis 1, 2
• Same dosing: 40-80 mg once daily as in non-dialysis patients 5
• Hemodialysis patients showed excellent blood pressure control (71.4% DBP control, 92.9% SBP response) with telmisartan 5

Hepatic Impairment

• Use with caution: Plasma concentrations increase and bioavailability approaches 100% in hepatic insufficiency 1
• Consider lower initial doses in patients with both renal and hepatic impairment, though specific guidance is not provided 1