gentamicin vs tobramycin
Side-by-side comparison of gentamicin and tobramycin Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Garamycin
Tobi, Nebcin
Gentamicin is an antibiotic medicine. It fights serious infections caused by certain bacteria.
Tobramycin is an antibiotic medicine. It fights serious bacterial infections in your body.
Gentamicin treats serious infections caused by certain bacteria. This includes infections in the blood, brain (meningitis), urinary tract, lungs, stomach area, skin, bone, and soft tissues. It can also treat bacterial infections in newborns.
Tobramycin treats serious infections caused by bacteria. This includes infections in the blood, lungs, brain (meningitis), belly, skin, bones, and urinary tract. It is used when other antibiotics might not work or are too harmful.
Gentamicin belongs to a class of drugs called aminoglycoside antibiotics. It works by stopping the growth of bacteria. This helps your body fight off the infection.
Tobramycin belongs to a class of drugs called aminoglycoside antibiotics. It works by stopping the growth of bacteria. This helps your body fight off the infection.
No common side effects listed.
- • Nausea
- • Vomiting
- • Diarrhea
- • Headache
- • Lethargy
- Drug Ineffective 1,014
- Acute Kidney Injury 999
- Pyrexia 751
- Off Label Use 677
- Renal Failure 603
- Off Label Use 1,939
- Death 1,666
- Infective Pulmonary Exacerbation Of Cystic Fibrosis 1,559
- Pneumonia 1,450
- Dyspnoea 1,373
Gentamicin can potentially damage kidneys and cause nerve damage, including hearing loss. The risk is higher if you have kidney problems, receive high doses, or take it for a long time. Tell your doctor right away if you notice dizziness, ringing in your ears, changes in hearing, or kidney problems.
Tobramycin can potentially damage your hearing and kidneys. Tell your doctor if you have kidney problems or hearing loss before starting this medicine. Your doctor will monitor your kidney and hearing function during treatment. Report any dizziness, ringing in the ears, or changes in hearing or kidney function to your doctor right away.
Tell your doctor if you are pregnant or breastfeeding. Gentamicin may harm your unborn baby. It is not known if gentamicin passes into breast milk.
Tell your doctor if you are pregnant or breastfeeding. Tobramycin may harm your unborn baby. It is not known if tobramycin passes into breast milk.
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How to Read This gentamicin vs tobramycin Comparison
gentamicin is classified in the Aminoglycoside Antibiotic drug class, while tobramycin sits within the Aminoglycoside Antibiotic class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, gentamicin has 4,044 submissions while tobramycin has 7,987. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between gentamicin and tobramycin — always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.