Questions

Gentamicin is an aminoglycoside that have bactericidal activity against Gram-negative bacteria. After iv administration of gentamicin the entire dose is excreted unchanged in urine, while after oral gentamicin administration about 1% of the oral dose is excreted unchanged in urine. This can be explained by:

1 - Gentamicin undergoes hepatic metabolism during the first pass-effect 2 - Gentamicin nephrotoxicities inhibited its renal elimination 3 - Gentamicin is eliminated mainly by metabolism after oral administration 4 - Gentamicin oral bioavailability is only 1%