Schedule H

Intravenous (IV), Intramuscular (IM), Topical (ophthalmic, otic, dermal)

Formulation Strength

Injection (IV/IM) 10 mg/mL, 40 mg/mL (1 mL and 2 mL ampoules)

Ophthalmic solution 0.3%

Ear drops 0.3% (single or combination with steroids)

Cream/Ointment (topical) 0.1%

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Serious Gram-negative Infections

(Including Pseudomonas aeruginosa, Enterobacteriaceae — septicaemia, intra-abdominal infections, complicated UTI, hospital-acquired pneumonia)

Adults — IV/IM Systemic Therapy:

Parameter Recommendation

Starting dose 5–7 mg/kg IV or IM once daily (extended-interval dosing preferred)

Titration Adjust based on renal function and therapeutic drug monitoring (TDM)

Usual maintenance dose 5–7 mg/kg/day once daily OR 1.5–2 mg/kg every 8 hours (divided dosing)

Maximum dose 7 mg/kg/day (higher doses require specialist supervision and TDM)

Clinical Notes:

• Commonly used in combination with β-lactam antibiotics (e.g., piperacillin-tazobactam, ceftriaxone) for synergistic effect

• Duration: Typically 5–7 days; extended courses (>7 days) increase toxicity risk

• Once-daily dosing preferred for most indications except bacterial endocarditis

• Calculate dose using actual body weight; use adjusted body weight if obese (>20% above IBW)

1. Bacterial Endocarditis (Synergy with β-lactam or Vancomycin)

(Enterococcal or Staphylococcal endocarditis)

Parameter Recommendation

Starting dose 1 mg/kg IV every 8 hours (divided dosing mandatory)

Titration Adjust based on TDM and renal function

Usual maintenance dose 1 mg/kg every 8 hours (total 3 mg/kg/day)

Maximum dose 3 mg/kg/day

Clinical Notes:

• Duration: 2 weeks for native valve; 4–6 weeks for prosthetic valve (as per organism and protocol)

• Must be used in combination — never as monotherapy

• Extended-interval dosing not recommended for endocarditis

• Specialist (cardiologist/ID physician) supervision mandatory

1. Topical Use — Ophthalmic Infections

(Bacterial conjunctivitis, blepharitis, corneal ulcer)

Parameter Recommendation

Starting dose 1–2 drops of 0.3% solution into affected eye(s) every 4 hours

Titration Not applicable

Usual maintenance dose 1–2 drops every 4–6 hours

Maximum dose Not applicable; duration typically 7–10 days

1. Topical Use — Otic Infections

(Otitis externa)

Parameter Recommendation

Starting dose 2–3 drops into affected ear canal three times daily

Titration Not applicable

Usual maintenance dose 2–3 drops TID for 7–10 days

Maximum dose Not applicable

Clinical Note: Avoid if tympanic membrane perforation suspected unless under ENT supervision

1. Topical Use — Skin Infections

(Superficial pyoderma, infected wounds, impetigo)

Parameter Recommendation

Starting dose Apply thin layer of 0.1% cream/ointment to affected area

Titration Not applicable

Usual maintenance dose Apply 2–3 times daily for 7–10 days

Maximum dose Not applicable

Secondary Indications — Adults Only (Off-label, if any)

Indication Dose Duration Notes Evidence

Inhaled gentamicin for MDR Gram-negative ventilator-associated pneumonia 80 mg nebulised every 8–12 hours (via jet nebuliser) 7–14 days OFF-LABEL; ICU specialist only; adjunct to systemic therapy Indian ICU protocols; observational data; limited RCTs

PAEDIATRIC DOSING (Specialist Only)

Primary Indications (Approved / Standard in India)

1. Neonatal Sepsis and Meningitis

(IAP/AIIMS/NNF Protocols)

Age/Weight Category Dose (IV/IM) Frequency

Preterm (<34 weeks GA), ≤7 days 4 mg/kg Every 36 hours

Preterm (<34 weeks GA), >7 days 4 mg/kg Every 24 hours

Term (≥34 weeks GA), ≤7 days, <2.5 kg 4 mg/kg Every 24 hours

Term (≥34 weeks GA), ≤7 days, ≥2.5 kg 4–5 mg/kg Every 24 hours

Term (≥34 weeks GA), >7 days 5 mg/kg Every 24 hours

Clinical Notes:

• Duration: 7–10 days for sepsis; 14–21 days for meningitis

• Monitor serum creatinine and urine output

• Consider audiometry/OAE before discharge if therapy >7 days

1. Serious Infections in Infants and Children (>1 month)

(Sepsis, complicated UTI, intra-abdominal infections)

Parameter Recommendation

Starting dose 5–7.5 mg/kg/day IV/IM

Titration Adjust based on clinical response and renal function

Usual maintenance dose 5–7.5 mg/kg/day given as once daily OR 2.5 mg/kg every 8 hours

Maximum dose 7.5 mg/kg/day

Clinical Notes:

• Once-daily dosing preferred in children with normal renal function

• Duration: 7–10 days typical; minimise duration to reduce toxicity

• TDM recommended if therapy >5 days

Secondary Indications — Paediatric Doses (Off-label, if any)

Indication Dose Duration Notes Evidence

Inhaled gentamicin for chronic Pseudomonas colonisation (cystic fibrosis) 40 mg nebulised twice daily Long-term maintenance OFF-LABEL; Specialist only (paediatric pulmonologist) Limited use in India; international CF guidelines

Safety Statement:

• Use in neonates requires strict adherence to gestational age and weight-based protocols

• Not recommended for >14 days in neonates without ENT/neonatal specialist involvement due to ototoxicity risk

• Monitor renal function and auditory function in all paediatric patients receiving systemic therapy

Critical importance — aminoglycoside toxicity is directly related to drug accumulation

Creatinine Clearance (CrCl) Dose Adjustment

60 mL/min Standard dosing (5–7 mg/kg once daily)

40–60 mL/min 4–5 mg/kg every 24 hours OR standard dose every 36 hours

20–40 mL/min 3–4 mg/kg every 48 hours OR per TDM

<20 mL/min 2 mg/kg; redose based on TDM; specialist supervision

Haemodialysis 1–1.7 mg/kg after each dialysis session (supplemental dose)

CAPD 0.6 mg/kg loading, then per levels

CRRT 1–2 mg/kg every 24–48 hours; adjust per TDM

Notes:

• Therapeutic drug monitoring (TDM) strongly recommended if therapy >5 days or in renal impairment

• Target trough level: <1–2 mcg/mL (to minimise nephrotoxicity)

• Target peak level (if measuring): 5–10 mcg/mL (for efficacy)

• Known hypersensitivity to gentamicin or any other aminoglycoside (cross-sensitivity exists)

• Myasthenia gravis — risk of severe neuromuscular blockade and respiratory failure

• Concurrent use with other aminoglycosides

• Pre-existing severe sensorineural hearing loss (unless life-threatening infection with no alternative)

• Pre-existing renal impairment — dose adjustment and monitoring essential

• Elderly patients — reduced renal reserve; increased toxicity risk

• Prolonged therapy (>7 days) — significantly increased ototoxicity and nephrotoxicity risk

• Concurrent nephrotoxic or ototoxic agents (loop diuretics, vancomycin, amphotericin B, NSAIDs)

• Dehydration or hypovolaemia — correct before initiating therapy

• Neuromuscular disorders (other than myasthenia gravis) — monitor closely

• Patients receiving neuromuscular blocking agents during surgery

• Vestibular dysfunction — baseline and ongoing assessment recommended

• Obesity — use adjusted body weight for dosing

• Burns patients — may require higher doses due to altered pharmacokinetics

Parameter Recommendation

Risk category Generally avoid — risk of fetal ototoxicity and nephrotoxicity (irreversible VIII cranial nerve damage reported)

Preferred alternatives β-lactams (ampicillin, ceftriaxone) or aztreonam if organism susceptible

When to use Only in life-threatening infections where no safer alternative exists; specialist input mandatory

Monitoring Fetal growth (serial ultrasound); amniotic fluid volume; neonatal hearing assessment after delivery

Parameter Recommendation

Compatibility Compatible with breastfeeding — poorly absorbed orally by infant

Preferred alternatives Amoxicillin, cephalosporins (if suitable for infection)

Drug levels in milk Low (minimal oral bioavailability in infant)

Infant monitoring Loose stools, oral thrush (theoretical effect on gut flora); feeding adequacy

Parameter Recommendation

Starting dose Lower end of dosing range (3–5 mg/kg/day); calculate based on estimated CrCl

Titration Slower; guided by TDM and renal function monitoring

Special risks Age-related decline in renal function (often not reflected in serum creatinine); vestibular toxicity; pre-existing hearing impairment; falls risk due to vestibular effects

Monitoring Renal function every 2–3 days; TDM if therapy >5 days; baseline and periodic audiometry if feasible

Interacting Drug/Class Effect Mechanism Management

Amphotericin B Synergistic nephrotoxicity Additive renal tubular toxicity Avoid combination if possible; if essential, aggressive hydration and daily renal monitoring

Vancomycin Increased nephrotoxicity risk Additive renal toxicity Monitor renal function daily; TDM for both drugs

Loop diuretics (furosemide, bumetanide) Increased ototoxicity and nephrotoxicity Additive toxicity; diuretics may enhance aminoglycoside entry into inner ear Avoid concurrent use if possible; if essential, avoid rapid IV bolus of diuretic

Cisplatin Potentiation of ototoxicity and nephrotoxicity Additive damage to cochlea and renal tubules Avoid combination

Cyclosporine, tacrolimus Synergistic nephrotoxicity Additive renal vasoconstriction and tubular toxicity Monitor renal function closely; consider alternative antibiotic

Neuromuscular blocking agents (vecuronium, rocuronium) Prolonged paralysis; respiratory failure Aminoglycosides have intrinsic neuromuscular blocking properties Use with extreme caution; monitor respiratory function; may need prolonged ventilatory support

Other aminoglycosides (amikacin, tobramycin) Additive oto- and nephrotoxicity Same class toxicity Avoid concurrent use

Interacting Drug/Class Effect Management

β-lactam antibiotics (penicillins, cephalosporins) Synergistic antibacterial effect; minor additive nephrotoxicity with some cephalosporins Monitor renal function; preferred combination for serious infections

NSAIDs Reduced renal perfusion; increased gentamicin accumulation Monitor renal function; avoid prolonged concurrent use

Acyclovir Additive nephrotoxicity Monitor renal function; ensure adequate hydration

IV contrast agents Additive nephrotoxicity Space administration if possible; hydration before and after contrast

Colistin Additive nephro- and neurotoxicity Monitor renal function and for neurotoxicity; TDM for both agents

Methotrexate Reduced methotrexate clearance Monitor methotrexate levels; watch for toxicity

• Injection site pain (IM administration)

• Transient elevation in serum creatinine

• Nausea, vomiting

• Rash

• Vestibular disturbance (dizziness, vertigo — especially with prolonged therapy)

• Tinnitus

• Headache

• Fever

Adverse Effect Action Required

Nephrotoxicity (acute tubular necrosis) Discontinue or reduce dose; supportive care; usually reversible if detected early

Ototoxicity — Cochlear (hearing loss) May be irreversible; discontinue immediately if detected; audiometry follow-up

Ototoxicity — Vestibular (vertigo, ataxia) Discontinue; often irreversible; vestibular rehabilitation may be needed

Neuromuscular blockade (respiratory paralysis) Rare; discontinue; supportive ventilation; calcium gluconate may help

Anaphylaxis Discontinue immediately; emergency management

C. difficile-associated diarrhoea Rare with aminoglycosides; discontinue if severe; treat per protocol

Phase Parameters

Baseline Serum creatinine; BUN; urinalysis; baseline audiometry (if prolonged therapy anticipated or pre-existing risk factors); complete clinical assessment; weight for dose calculation

During treatment Renal function (creatinine, urine output) every 2–3 days; daily in critically ill or renal impairment; clinical assessment for vestibular symptoms (dizziness, nystagmus); signs of ototoxicity

Therapeutic drug monitoring (TDM) Recommended if therapy >5 days, renal impairment, or high-dose therapy; Peak: 5–10 mcg/mL (30 min post-infusion); Trough: <1–2 mcg/mL (pre-dose)

Long-term / Repeated exposure Audiometry before and after therapy; vestibular function assessment; cumulative dose tracking

Brand Name Manufacturer Formulations

Garamycin Abbott Injection 40 mg/mL, 80 mg/2mL

Genticyn Alkem Injection 40 mg/mL; Eye/Ear drops 0.3%

G-Mycin Ranbaxy Injection 40 mg/mL

Gentamax Cipla Injection 20 mg/2mL, 80 mg/2mL

Genta Various Injection; ophthalmic drops

Otogesic (combination) Various Ear drops (Gentamicin + Beclomethasone)

Note: Multiple generic brands available; combination ear drops with steroids commonly used

Notes:

• Included in NLEM 2022 (injection formulation)

• NPPA price-controlled for scheduled formulations

• Widely available in government hospital supply

1. Limit duration to minimise toxicity: Systemic gentamicin therapy should ideally not exceed 5–7 days; every additional day increases nephro- and ototoxicity risk significantly

1. Once-daily dosing is preferred: Extended-interval (once-daily) dosing provides equivalent efficacy with potentially lower toxicity than divided dosing — except in endocarditis and pregnancy where divided dosing is standard

1. Concurrent loop diuretics are high-risk: The combination of gentamicin with furosemide dramatically increases ototoxicity — avoid if possible, or use alternative diuretic

1. TDM is underutilised in India: Therapeutic drug monitoring improves outcomes and reduces toxicity; advocate for TDM availability, especially in tertiary care settings

1. Topical preparations are not for deep infections: Gentamicin ear/eye drops have poor penetration; systemic therapy required for severe or invasive infections

1. Weight-based dosing requires actual body weight: Use actual body weight for dosing; in obese patients (>20% above ideal body weight), use adjusted body weight = IBW + 0.4 × (actual weight – IBW)

gentamicin; aminoglycoside; antibacterial; nephrotoxic; ototoxic; neonatal sepsis; gram-negative infections; ICU antibiotic; renal-adjusted; TDM required; NLEM India; Schedule H; infectious diseases

RxIndia v1.0 — 10 Jun 2025

• CDSCO (Central Drugs Standard Control Organisation)

• Indian Pharmacopoeia / National Formulary of India (IP/NFI)

• NLEM 2022

• ICMR Treatment Guidelines for Antimicrobial Use

• IAP Neonatology Drug Doses (NNF)

• AIIMS Neonatology and Antibiotic Guidelines

• API Textbook of Medicine

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• Harrison's Principles of Internal Medicine

• Product Inserts: Garamycin (Abbott), Genticyn (Alkem)