Drug reference

Tobramycin

Aminoglycoside antibiotic · Antibiotic

Also known as Tobramycin Sulfate, Nebcin, Tobi, Bethkis, Kitabis Pak, Tobrex

START

Extended-interval preferred: 5-7 mg/kg IV q24h; check baseline creatinine, calculate eGFR, obtain audiogram if prolonged course; TDM strongly recommended

TYPICAL MAX

7 mg/kg/day

STOP IF

eGFR decline >50% from baseline, signs of ototoxicity (tinnitus, hearing loss, vertigo), therapeutic alternatives available, course complete (usually 7-14 days)

WATCH

Serum creatinine daily, peak and trough levels (or random levels with once-daily), hearing/vestibular symptoms, concurrent nephrotoxins, drug levels (target peak 20-30 mcg/mL, trough <1 mcg/mL for traditional dosing)

CDSCO approvedATC J01GB01

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 30min · Rapid bactericidal onset
PEAK: 30min · IV peak
t½: 2.5h · 2-3 hours (normal renal function)
DURATION: 1d · 24-hour coverage (extended-interval)

EXCRETION

Renal (95%, unchanged)

route + CYP

INTERACTIONS

12 major

SEVERE in our sources

PREGNANCY

Avoid in pregnancy unless no alternative; ototoxicity risk to fetus; Category D

FDA category + note

Top interactionssee all 12 →

FurosemideSevereTextbook-citedKDT 7e · p949
Amphotericin BSevereDatabaseKimi deep-research + Cla
AtracuriumSevereDatabaseDDInter
BacitracinSevereDatabaseDDInter

Available in India

193 branded formulations and 19 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Mechanism

Binds irreversibly to 30S ribosomal subunit, inhibiting bacterial protein synthesis. Bactericidal against aerobic Gram-negative bacilli including Pseudomonas aeruginosa, Enterobacterales, and Acinetobacter. Poor activity against anaerobes and most Gram-positive organisms (except Staphylococcus aureus in combination).

Indications

Serious Gram-negative infections (sepsis, pneumonia, UTI, intra-abdominal)Cystic fibrosis (inhaled - chronic Pseudomonas suppression)Endocarditis (in combination with beta-lactams)Meningitis (in combination with beta-lactams, intrathecal/intraventricular)Neutropenic fever (in combination)External eye infections (topical)

Dosing

Adult: IV/IM: 3-5 mg/kg/day in 1-3 divided doses (traditional) OR extended-interval: 5-7 mg/kg q24h (once-daily). Inhaled: 300 mg BD via nebulizer (Bethkis) or 300 mg q12h (Tobi). Intrathecal: 4-8 mg/day
Pediatric: >1 week: 2-2.5 mg/kg q8h IV/IM. Cystic fibrosis: higher doses (3-3.3 mg/kg q8h) due to altered PK
Renal adjustment: Essential - see renal zones. Nephrotoxic and renally cleared
Hepatic adjustment: No adjustment needed
Geriatric: Reduce dose; monitor renal function and drug levels closely; increased nephrotoxicity and ototoxicity risk
Max dose: 7 mg/kg/day (extended-interval); 5 mg/kg/day (traditional divided dosing)

Pharmacokinetics

Onset

Rapid bactericidal effect

Peak effect

IV: 30 minutes; IM: 30-90 minutes

Duration

8-12 hours

Half-life

2-3 hours (normal renal function); 50-70 hours (anuria)

Bioavailability

PO: <1%; IM/IV: complete

Protein binding

<10%

Metabolism

Minimal; not metabolized

Excretion

Renal (unchanged drug, ~95%)

Contraindications

Hypersensitivity to tobramycin or other aminoglycosides
Myasthenia gravis (may worsen neuromuscular blockade)

Side effects

Common

Nephrotoxicity (10-25% - reversible, dose-related)Ototoxicity (8-10% - may be irreversible): vestibular > cochlearNeuromuscular blockade (rare)

Serious

Acute kidney injury (dose-limiting toxicity)
Irreversible hearing loss
Vestibular dysfunction (vertigo, ataxia)
Anaphylaxis (rare)
Severe neuromuscular blockade / respiratory paralysis (rare, with rapid IV or anesthesia)

Pregnancy & lactation

Pregnancy

Avoid in pregnancy unless no alternative; ototoxicity risk to fetus; Category D

Lactation

Excreted in breast milk in small amounts; compatible with breastfeeding per AAP; monitor infant for diarrhea and thrush

Drug interactions

Furosemide

Severe

Textbook-cited

Ototoxicity (hearing loss) and nephrotoxicity.

Avoid concurrent use; if unavoidable, monitor renal function and audiometry

Source: KDT 7e · p949

Amphotericin B

Severe

Database

Additive nephrotoxicity

Avoid if possible; monitor renal function closely

Source: Kimi deep-research + Cla

Atracurium

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Bacitracin

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Botulinum Toxin Type A

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Botulinum Toxin Type B

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Bumetanide

Severe

Database

Drug interaction classified as: synergy.

Source: DDInter

Capreomycin

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Cidofovir

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Cisatracurium

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Cisplatin

Severe

Database

Increased risk of severe nephrotoxicity and ototoxicity (hearing loss, tinnitus). Both drugs are independently nephrotoxic and ototoxic.

Avoid concomitant use if possible. If co-administration is unavoidable, monitor renal function and auditory function very closely. Adjust tobramycin dose based on renal function. Consider alternative antibiotics.

Source: DDInter

Colistimethate

Severe

Database

Drug interaction classified as: synergy

Source: DDInter