[Vancomycin intoxication in a patient with inappropriate antidiuretic hormone syndrome and diarrhea]

Area of Science:

• Pharmacology
• Nephrology
• Oncology

Background:

• Vancomycin is a critical antibiotic for Gram-positive bacterial infections, requiring therapeutic drug monitoring to avoid toxicity and ensure efficacy.
• Established therapeutic ranges (10-20 mg/L) aim to prevent nephrotoxicity and ototoxicity from high levels, and resistance from low levels.
• Vancomycin-induced nephrotoxicity is rare with standard dosing but can be exacerbated by factors like renal hypoperfusion.

Observation:

• A case of unexpected vancomycin nephrotoxicity is presented.
• The patient exhibited Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH) associated with a paraneoplastic condition.
• Renal hypoperfusion may have contributed to pre-renal damage and impaired vancomycin elimination.

Findings:

• The patient developed nephrotoxicity despite standard vancomycin monitoring protocols.
• The underlying paraneoplastic syndrome and SIADH likely complicated vancomycin pharmacokinetics.
• Elevated serum creatinine indicated pre-renal damage, leading to reduced antibiotic clearance.

Implications:

• This case highlights the potential for vancomycin nephrotoxicity even in seemingly standard therapeutic scenarios.
• Complex conditions like paraneoplastic SIADH necessitate vigilant monitoring and potential dose adjustments for vancomycin.
• Understanding drug interactions and patient-specific factors is crucial for optimizing vancomycin therapy and preventing adverse events.