Gentamicin
J01G - Aminoglycoside antibacterials
ATC J01GB03
Small molecule
approved 1970
Parenteral
Topical
Narrow therapeutic index
Black-box warning
🧬 Cross-allergy: Aminoglycosides
JFDA label: Ultragent Vials
⚠ Black-Box Warning
Mechanism of Action
Interferes with bacterial protein synthesis by binding to 30S ribosomal subunit resulting in a defective bacterial cell membrane
Indications
Approved
- Dermatologic infections
Antimicrobial Spectrum
Expected / intrinsic spectrum (EUCAST breakpoints & labels) — not local resistance. Source: EUCAST v16 · curated · openfda-label.
Bacteria
| Organism | Activity | MIC |
|---|---|---|
| Acinetobacter spp. | Susceptible | 41.0 mg/L |
| Enterobacterales | Susceptible | 21.0 mg/L |
| Enterococcus faecalis | Susceptible | 128.0 mg/L |
| Escherichia coli | Susceptible | 2.0 mg/L |
| Klebsiella pneumoniae | Susceptible | 2.0 mg/L |
| Pseudomonas aeruginosa | Susceptible | 4.0 mg/L |
| Staphylococcus aureus | Susceptible | 1.0 mg/L |
| Streptococcus pneumoniae | Active | — |
| Escherichia coli | Resistant | 4.0 mg/L |
| Pseudomonas aeruginosa | Resistant | 4.0 mg/L |
| Staphylococcus aureus | Resistant | 1.0 mg/L |
Class profile
| gramStatus | Both |
|---|---|
| spectrumBreadth | Moderate |
| atypicalCoverage | No |
| isBactericidal | 1 |
| moaCategory | Protein synthesis inhibitor (30S ribosomal) |
| pdIndex | Concentration-dependent |
| postAntibioticEffect | Prolonged |
| mrsaCoverage | 0 |
| resistanceMechanisms | Aminoglycoside-modifying enzymes,Ribosomal methylation,Reduced outer membrane permeability |
Contraindications
Source: Lexicomp
- Hypersensitivity to gentamicin or any component of the formulation Absolute
Adverse Reactions
Very Common >10%Common 1–10%Uncommon 0.1–1%
Rare 0.01–0.1%Very Rare <0.01%Not Known
Nervous system disorders (1)
Very Rare Neuromuscular blockade
Renal and urinary disorders (1)
Common Nephrotoxicity (tubular necrosis)
Skin and subcutaneous tissue disorders (2)
Not Known Erythema · pruritus
Ear and labyrinth disorders (2)
Common Ototoxicity (auditory: high-frequency hearing loss)
Uncommon Vestibular toxicity (vertigo, ataxia)
Dosing
Source: Lexicomp
Dermatologic infections: Topical: Apply 3 to 4 times daily to affected area
(For additional information see "Gentamicin (topical): Pediatric drug information ") Dermatologic infections: Infants, Children, and Adolescents: Refer to adult dosing.
Refer to adult dosing.
Warnings & Precautions
Source: Lexicomp
Superinfection
Prolonged use may result in fungal or bacterial superinfection; discontinue if superinfection is noted.
Sensitization
Topical use has been associated with local sensitization (redness, irritation); discontinue if sensitization is noted. Other warnings/precautions:
Long-term use
Not intended for long-term therapy.
Pregnancy & Lactation
Pregnancy
Lactation
Caution
Hale L3
Maternal use of an ear drop or eye drop that contains gentamicin presents little or no risk for the nursing infant.
LactMed: monitor the infant.
Monitoring
| Efficacy | For once-daily dosing: Hartford nomogram or gentamicin concentration 6–14 h post-dose; for multiple-daily dosing: trough < 2 mg/L, peak 5–10 mg/L; renal function |
|---|---|
| Toxicity | Nephrotoxicity (SCr, urine output); ototoxicity (auditory: high-frequency hearing loss; vestibular: balance disturbances); trough accumulation |
| Clinical pearl | Once-daily dosing (eg 5–7 mg/kg) achieves concentration-dependent bactericidal killing and allows trough concentrations to fall below the nephrotoxicity threshold. Avoid prolonged therapy beyond 7–10 days where possible. |
| Counseling | Report hearing changes, ringing in ears, dizziness, or decreased urination. Stay well hydrated. Avoid other ototoxic or nephrotoxic drugs. |
Chemistry & Properties
| Formula | C21H43N5O7 |
|---|---|
| Molecular weight | 477.6 g/mol |
| IUPAC name | 2-[4,6-diamino-3-[3-amino-6-[1-(methylamino)ethyl]oxan-2-yl]oxy-2-hydroxycyclohexyl]oxy-5-methyl-4-(methylamino)oxane-3,5-diol |
| CAS | 1403-66-3 |
| PubChem CID | 3467 |
| InChIKey | CEAZRRDELHUEMR-UHFFFAOYSA-N |
| logP | -4.1 (XLogP -4.1) |
| Polar surface area | 200.0 Ų |
| H-bond acceptors / donors | 12 / 8 |
SMILES
CC(C1CCC(C(O1)OC2C(CC(C(C2O)OC3C(C(C(CO3)(C)O)NC)O)N)N)N)NCBiology & Pharmacokinetics
Pharmacokinetics
| BBB penetrant | No |
|---|
Enzyme interactions
| Enzyme | Role | Detail |
|---|---|---|
| CYP2C19 | Substrate | — |
| CYP2D6 | Substrate | — |
| CYP3A4 | Substrate | — |
Receptor binding (top 1)
| Target | Action | Affinity |
|---|---|---|
| TRPV5 (TRPV5) | Inhibitor | pIC50 6.0 |
Transporters
BCRP (Inhibitor)BSEP (Inhibitor)MRP1 (Inhibitor)OAT1 (Inhibitor)OAT3 (Inhibitor)OATP1B1 (Inhibitor)OATP1B1 (Inhibitor)OATP1B3 (Inhibitor)OATP1B3 (Inhibitor)P-gp (Inhibitor)MRP2 (Substrate)P-gp (Substrate)
Drug–drug interactions (100+, DDInter)
| Interacting drug | Severity | Management |
|---|---|---|
| Agalsidase beta | major | |
| Atracurium | major | |
| Bacitracin | major | |
| Botulinum Toxin Type B | major | |
| Botulinum toxin type A | major | |
| Bumetanide | major | |
| Capreomycin | major | |
| Cidofovir | major | |
| Cisatracurium | major | |
| Colistimethate | major | |
| Deferasirox | major | |
| Diatrizoate | major | |
| Doxacurium | major | |
| Etacrynic acid | major | |
| Everolimus | major | |
| Foscarnet | major | |
| Furosemide | major | |
| Gallium nitrate | major | |
| Human Rho(D) immune globulin | major | |
| Human botulinum neurotoxin A/B immune globulin | major | |
| Human cytomegalovirus immune globulin | major | |
| Human immunoglobulin G (intravenous and subcutaneous) | major | |
| Human immunoglobulin G (intravenous) | major | |
| Inotersen | major | |
| Iodipamide | major | |
| Iodixanol | major | |
| Iohexol | major | |
| Iopamidol | major | |
| Iopromide | major | |
| Iothalamic acid | major | |
| Ioversol | major | |
| Ioxilan | major | |
| Magnesium sulfate | major | |
| Mannitol | major | |
| Metocurine | major | |
| Mivacurium | major | |
| Pancuronium | major | |
| Pipecuronium | major | |
| Polymyxin B | major | |
| Rapacuronium | major |
Showing 40 of 100+.
Registered Products (15)
| Brand | Form / strength | Pack | Agent | Citizen (JOD) |
|---|---|---|---|---|
| Ophtagram e/o | Ophthalmic Ointment 0.3 % | 5 g tube | Petra Drug Store | 0.610 |
| Apigen eye ointment | Ointment 3 mg/g | 5 g tube | Amman Pharmaceutical Industries Co | 0.650 |
| Ultragent Vials | Vial 20 mg/2 ml | 1 vial | The Arab Pharmaceutical Manufactruing Co. | 0.710 |
| Apigen eye ear drops | Ophthalmic Solution 3 mg/ml | 10 ml | Amman Pharmaceutical Indusries | 0.750 |
| GENTADAR Eye/Ear DROPS. | Ophthalmic Solution 3 mg/ml | 10 ml | Dar Al Dawa Development and Investment Co Ltd/Jordan | 0.750 |
| Gentadex eye ear drops | Ophthalmic Solution 0.3 %, 0.1 % | 10 ml | Amman Pharmaceutical Industries Co | 1.150 |
| Ultragent Vials | Vial 80 mg/2 ml | 1 vial pack varies | The Arab Pharmaceutical Manufactruing Co. | 1.210 |
| Gentadexa Eye,Ear Drop | Ear Drops 0.3 %, 0.1 % | 10 ml | Jarzeem Drug Store | 2.000 |
| Indobiotic | Solution 300.000 IU/100 ml | 5 ml | Petra Drug Store | 3.020 |
| Minims Gentamicin Sulph.0.3% W/Ve/d | Solution 0.3 % | 0.5 ml | Petra Drug Store | 3.950 |
| GENTAMED AMP | Ampoule (as Sulphate) 80 mg/2 ml | 10 amp pack varies | Al Hilal Drug Store | 4.200 |
| Gentazole-B | Cream Betamethasone Dipropionate 0.064 %WW, Clotrimazole 1.00 %WW, Gentamicin Sulphate 0.1 %WW | (30 GM) / TUB | Sana Pharmaceutical Industry Co. | 4.800 |
| Getamine | Vial 80 mg/2 ml | 10 vial | MS PHARMA/JORDAN | 5.380 |
| GENTAMED AMP | Ampoule (as Sulphate) 80 mg/2 ml | 100 amp pack varies | Al Hilal Drug Store | 37.820 |
| Ultragent Vials | Vial 80 mg/2 ml | 50 vial pack varies | The Arab Pharmaceutical Manufactruing Co. | 51.430 |