Absorption: Minimal systemic absorption, but may accumulate in patients with renal failure.
Distribution: Widely distributed throughout extracellular fluid; crosses the placenta; small amounts enter breast milk. Poor penetration into CSF.
Metabolism/Excretion: Excretion is >90% renal.
Half-life: 2–4 hr (increased in renal impairment).
GI: diarrhea, nausea, vomiting.
Misc: hypersensitivity reactions.
Interactions are listed for systemically absorbed drug
Drug-Drug:
- May enhance possible respiratory paralysis after inhalation anesthetics or neuromuscular blockers.
- ↑incidence of ototoxicity with loop diuretics.
- ↑incidence of nephrotoxicity with other nephrotoxic drugs.
- May ↑anticoagulant effects of warfarin.
- May ↓absorption of digoxin and methotrexate.
Preoperative Intestinal Antisepsis
- PO (Adults): 1 g every hr for 4 doses, then 1 g every 4 hr for 5 doses or 1 g at 1 PM, 2 PM, and 11 PM on day before surgery.
- PO (Children): 15 mg/kg every 4 hr for 2 days or 25 mg/kg at 1 PM, 2 PM, and 11 PM on day before surgery.
Hepatic Encephalopathy
- PO (Adults): 1–3 g every 6 hr for 5–6 days; may be followed by 4 g/day chronically.
- PO (Children): 12.5–25 mg/kg every 6 hr for 5–6 days (max dose 12 g/day).
Therapeutic Classification: anti-infectives
Pharmacologic Classification: aminoglycosides
