Drug Interactions: Telmisartan, Rosuvastatin, Metosartan, Pantoprazole, Paroxetine, Ondansetron, Amikacin, Cefuroxime
Critical High-Risk Interactions
Telmisartan + Rosuvastatin: Clinically Significant Interaction Requiring Monitoring
The combination of telmisartan and rosuvastatin increases rosuvastatin exposure by approximately 26% (AUC) and doubles peak concentrations (Cmax), requiring dose adjustment and monitoring. 1, 2
- Rosuvastatin dose should not exceed 10 mg daily when combined with telmisartan to minimize myopathy and rhabdomyolysis risk 3, 1
- The interaction occurs through inhibition of OATP1B1 and OATP1B3 transporters, which are critical for rosuvastatin hepatic uptake 2
- Monitor for muscle soreness, tenderness, or pain at baseline, 6-12 weeks after initiation, and at each follow-up visit 4
- Check creatine kinase (CK) when muscle symptoms occur; discontinue if CK exceeds 10 times upper limit of normal with symptoms 4
Telmisartan: Hyperkalemia and Renal Dysfunction Risks
Monitor serum potassium and creatinine within 1-2 weeks of initiating telmisartan, especially with concurrent nephrotoxic agents (amikacin, cefuroxime). 5, 6
- Avoid potassium supplements, potassium-sparing diuretics, and potassium-containing salt substitutes when using telmisartan 6
- Risk of hyperkalemia increases substantially with eGFR <30 mL/min/1.73 m² (requires more frequent monitoring) 5
- In patients with diabetes and heart failure, hyperkalemia >5.5 mmol/L occurs in 11.8% of patients on ARBs 5
- Never combine telmisartan with ACE inhibitors or aliskiren due to excessive hyperkalemia and acute kidney injury risk without clinical benefit 7, 6, 8
Aminoglycoside (Amikacin) Nephrotoxicity Amplification
The combination of amikacin with telmisartan significantly increases acute kidney injury risk through additive renal toxicity mechanisms. 6
- Telmisartan reduces glomerular filtration through efferent arteriole vasodilation, while amikacin causes direct tubular toxicity 6
- Monitor serum creatinine and potassium every 2-3 days during concurrent therapy 6
- Consider holding telmisartan during short-course amikacin therapy if clinically feasible 6
- Ensure adequate hydration and avoid volume depletion, which exacerbates both drugs' renal effects 6
Moderate-Risk Interactions Requiring Awareness
Paroxetine (SSRI) Considerations
Paroxetine does not significantly interact with telmisartan or rosuvastatin through CYP450 pathways. 9, 10
- Telmisartan has no affinity for CYP450 enzymes and is not metabolized via this system 9, 10
- Rosuvastatin undergoes minimal CYP metabolism (primarily eliminated unchanged) 4
- Monitor for increased bleeding risk if patient is on concurrent anticoagulation, as SSRIs affect platelet function (not a direct drug interaction) 4
Pantoprazole (Proton Pump Inhibitor)
Pantoprazole does not clinically interact with telmisartan or rosuvastatin. 9, 10
- No CYP-mediated interaction with telmisartan (not CYP-metabolized) 9
- No significant effect on rosuvastatin absorption or metabolism 4
- Continue monitoring for general statin adverse effects per standard protocols 4
Ondansetron (5-HT3 Antagonist)
Ondansetron has no documented pharmacokinetic interactions with telmisartan, rosuvastatin, or other agents in this regimen. 9, 10
- No CYP-mediated interactions with telmisartan 9
- No transporter-mediated interactions with rosuvastatin 4
- Monitor QT interval if patient has cardiac risk factors (ondansetron can prolong QT, though not a direct drug interaction) 4
Cefuroxime (Cephalosporin Antibiotic)
Cefuroxime does not interact pharmacokinetically with telmisartan or rosuvastatin but shares nephrotoxicity concerns with amikacin. 6
- When combined with telmisartan and amikacin, monitor renal function closely (every 2-3 days) 6
- Ensure adequate hydration to minimize cumulative nephrotoxicity 6
Monitoring Algorithm for This Medication Regimen
Baseline Assessment (Before Initiating Combination)
- Serum potassium, creatinine, eGFR 5, 6
- Creatine kinase (CK) if muscle symptoms present 4
- Liver function tests (AST/ALT) for rosuvastatin 4
Week 1-2 After Initiation
- Recheck potassium and creatinine (critical window for telmisartan-induced hyperkalemia and AKI) 5, 6
- Assess for muscle symptoms (pain, tenderness, weakness) 4
Week 6-12 After Initiation
- Repeat potassium, creatinine 5
- Evaluate muscle symptoms and check CK if present 4
- Liver function tests (AST/ALT approximately 12 weeks after starting rosuvastatin) 4
Ongoing Monitoring
- Potassium and creatinine at each follow-up visit (every 3-6 months) 5
- Muscle symptom assessment at each visit 4
- Annual liver function tests for rosuvastatin 4
- Every 2-3 days during amikacin therapy: creatinine and potassium 6
Critical Pitfalls to Avoid
Do not use standard rosuvastatin doses (20-40 mg) with telmisartan—limit to 10 mg daily maximum 3, 1, 2
Do not add ACE inhibitors, aliskiren, or potassium supplements to this regimen containing telmisartan 7, 6
Do not ignore muscle symptoms in patients on rosuvastatin—check CK immediately and discontinue if CK >10× ULN with symptoms 4
Do not continue telmisartan without dose adjustment during acute illness, dehydration, or procedures that may precipitate AKI 11, 6
Do not overlook cumulative nephrotoxicity when combining telmisartan with amikacin and cefuroxime—intensify renal monitoring 6
Risk Stratification for Myopathy
Patients at highest risk for rosuvastatin-induced myopathy in this regimen: 4