Oral Aminoglycosides
Neomycin and paromomycin are the only aminoglycosides available for oral administration, but they are NOT used for systemic infections—they are used exclusively for local gastrointestinal effects.
Key Clinical Points
Aminoglycosides as a class are poorly absorbed from the gastrointestinal tract 1, 2, which fundamentally limits their oral use. This pharmacokinetic property means:
- Oral aminoglycosides do NOT achieve therapeutic systemic blood levels
- They remain in the GI tract and are excreted in stool
- Intravenous or intramuscular administration is required for systemic infections 2
Specific Oral Aminoglycosides and Their Uses
Neomycin
- Primary indication: Hepatic encephalopathy 3
- Secondary use: Surgical bowel preparation 4, 1
- Dosing for bowel prep: 1-2 g PO variable 4
- Limitation: Toxicity restricts use to irrigating/topical preparations, oral bowel prep, or hepatic coma 1
Paromomycin
- Sole indication: Treatment of amebic infections 3
- Not used for bacterial infections
Critical Caveat
Do not prescribe oral aminoglycosides expecting systemic antibacterial activity. For urinary tract infections, even simple cystitis due to carbapenem-resistant Enterobacteriaceae, guidelines recommend single-dose IV aminoglycoside (not oral) 5. The 2024 WHO guidelines and multiple other sources consistently specify IV or IM routes for aminoglycosides when treating infections 6, 7, 8, 9.
For Systemic Infections Requiring Aminoglycosides:
- Gentamicin: 5 mg/kg IV single dose 4
- Tobramycin: 5 mg/kg IV single dose 4
- Amikacin: 15 mg/kg IV single dose 4
The oral route is a therapeutic dead-end for systemic aminoglycoside therapy.