Major
Gentamicin × tacrolimus
Aminoglycoside antibiotic×Calcineurin inhibitor (immunosuppressant)
Mechanism
Additive nephrotoxicity via two distinct mechanisms. Gentamicin (an aminoglycoside) directly injures proximal renal tubules. Tacrolimus (calcineurin inhibitor) causes afferent arteriolar vasoconstriction. Co-administration sharply raises acute kidney injury risk, especially in transplant patients.
Symptoms
Reduced urine output, rising creatinine and urea. In kidney transplant patients: accelerated graft decline. Gentamicin ototoxicity too: tinnitus, hearing loss.
Management
Avoid the combination. Alternative antibiotics: a cephalosporin, carbapenem, or vancomycin (with its own renal monitoring). If gentamicin is irreplaceable: minimum effective dose, daily creatinine checks, and gentamicin level monitoring per protocol.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.