Aminoglycoside Antibiotic Pregnancy: There are limited data on the use of aminoglycosides in pregnancy. Gentamicin crosses the placenta and there is a risk of ototoxicity (vestibulocochlear nerve damage) and/or renal damage in the fetus, as seen in animal studies. Gentamicin should not be used in pregnancy except in life-threatening situations where the expected benefits outweigh the possible risks, and in such cases maternal serum concentration monitoring plus monitoring of the infant's hearing and renal function is recommended. Gentamicin is excreted in human breast milk and is detected in low concentrations in the serum of breast-fed infants; if the infant's serum concentration exceeds 1 microgram/ml, either breast-feeding or gentamicin therapy may need to be discontinued under medical supervision.

Gentamicin (Orthopaedic — Bone Cement and Systemic)

Brand names: Cidomycin, Garamycin, Simplex with Tobramycin (cement)

Gentamicin is an aminoglycoside antibiotic used in orthopaedics both systemically against Gram-negative and selected staphylococcal infections and locally as gentamicin-impregnated bone cement or beads for surgical-site and prosthetic-joint infection prophylaxis or treatment.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 3 to 5 mg/kg/day in adults with normal renal function, depending on the severity of infection, given as one single daily dose (preferred) or in two divided doses; dose calculations should be based on ideal body weight

Route: Intravenous or intramuscular — the recommended dose and precautions are identical for both. Intravenous doses should be injected directly into a vein or into the drip set tubing over no less than three minutes, or given by infusion over 20 to 30 minutes in no greater volume of fluid than 100 ml (up to 60 minutes, in particular for once-daily dosing). Once daily dosing should only be administered through the intravenous route

Frequency: Once daily (preferred) or in two divided doses. A dosing frequency of more than twice daily may be adopted for some specific pathogens or sites of infection as recommended in national and local guidance; once daily dosing is not recommended in endocarditis

SCOPE NOTE: the fetched UK SPC is 'Cidomycin 80mg/2ml Solution for Injection' (https://www.medicines.org.uk/emc/product/14742/smpc), which covers SYSTEMIC intravenous and intramuscular gentamicin only. It contains NOTHING on gentamicin-impregnated bone cement, beads or other local antibiotic carriers — that half of this page must be sourced by the clinician from the relevant device/product labelling and is not derivable from this SPC. The dose should be adjusted according to clinical response and serum concentration levels. Other indication-specific figure in the same §4.2: in patients with normal renal function, 160 mg once daily may be used for the treatment of urinary tract infections. MONITORING (mandatory): regular serum concentration monitoring is recommended for all patients, especially the elderly, newborns, the obese, patients with impaired renal function and patients with cystic fibrosis — gentamicin should not be prescribed if serum concentrations cannot be monitored. Pre-dose (trough) levels should not exceed 1 mg/L for once daily dosing or 2 mg/L for multiple daily dosing; levels above these indicate the need to extend the dose interval, not to reduce the dose. Post-dose (peak) levels should be measured one hour after an intravenous or intramuscular bolus, or 30 minutes after the end of an infusion: below 4 mg/L suggests the dose is likely to be inadequate and an increase should be considered, above 10 mg/L indicates increased risk of toxicity, particularly ototoxicity, and a dose reduction should be considered. Duration of therapy should be the shortest possible compatible with clinical recovery, since the risk of ototoxicity and nephrotoxicity relates to total exposure. ELDERLY: may be more susceptible to aminoglycoside toxicity; monitor closely with frequent gentamicin levels, assessment of renal function and signs of ototoxicity. OBESITY: monitor serum concentrations closely and consider a dose reduction. Consider alternatives in patients with mitochondrial DNA mutations (particularly m.1555A>G in the 12S rRNA gene) or a maternal history of aminoglycoside-induced deafness, as ototoxicity can occur even at therapeutic serum levels.

Paediatric dose

Route: Intravenous or intramuscular

Frequency: One single daily dose (preferred) or two divided doses; newborns are given the required daily dose as one single dose because of the longer half-life

Max: Not stated as an absolute paediatric maximum in this SPC; dosing is governed by serum concentration monitoring (trough not above 1 mg/L for once daily dosing or 2 mg/L for multiple daily dosing, peak above 10 mg/L indicates increased toxicity risk)

From SPC §4.2 — the figures are stated as ranges, so no single per-kg number is recorded and dosePerKg is left null deliberately. Children aged 1 year and above and adolescents with normal renal function: 3 to 6 mg/kg/day as one single dose (preferred) or two divided doses. Infants after the first month of life: 4.5 to 7.5 mg/kg/day as one single dose (preferred) or two divided doses. Neonates and pre-term infants (aged 0 to 4 weeks): 4 to 7 mg/kg/day, given as one single daily dose. Neonates and infants are an important risk group for ototoxicity. Serum concentration monitoring is mandatory. Verify all paediatric dosing against a children's formulary before use.

Dose adjustments

Renal

In impaired renal function the recommended daily dose must be decreased and adjusted to renal function, by reducing the dose and/or increasing the dose interval; serum peak and trough concentrations and renal function must be monitored frequently in all such patients. No clear recommendation can be made for once daily dosing — dosing should be guided by plasma concentration levels; where once daily dosing would otherwise be appropriate in moderate renal impairment, the dose interval should be at least 24 hours and extended according to the degree of impairment and gentamicin levels. Limited data exist in severe renal impairment (creatinine clearance below 30 ml/min) after once daily administration. The SPC's multiple-daily-dose table for adults: creatinine clearance above 70 ml/min — 80 mg 8 hourly; 30 to 70 ml/min — 80 mg 12 hourly; 10 to 30 ml/min — 80 mg daily; 5 to 10 ml/min — 80 mg every 48 hours; twice weekly intermittent haemodialysis (clearance below 5 ml/min) — 80 mg after dialysis; in each case 60 mg instead of 80 mg if body weight is under 60 kg. Nomograms based on age, weight and renal function are available and local guidance should be followed where available.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Myasthenia gravis

Side effects

Vestibular damage, transitory hearing loss, irreversible hearing loss and deafness — particularly after exposure to ototoxic drugs or in the presence of renal dysfunction (frequency not known)
Nephrotoxicity, usually reversible (frequency not known); acute renal failure and Fanconi-like syndrome after a prolonged course of high dose (very rare)
Vomiting (very common); nausea and stomatitis (frequency not known)
Hypersensitivity, anaphylaxis/anaphylactic reaction including anaphylactic shock; Stevens-Johnson syndrome, toxic epidermal necrolysis, rash, purpura, urticaria, pruritus (frequency not known)
Antibiotic-associated colitis including pseudomembranous colitis, superinfection with gentamicin-resistant bacteria, hypomagnesaemia on prolonged therapy, central neuropathy (convulsions, lethargy, encephalopathy) and peripheral neuropathy (frequency not known)

Clinical monograph

How it works

It binds the bacterial 30S ribosomal subunit to inhibit protein synthesis and is bactericidal; local cement/bead delivery achieves high regional concentrations with low systemic exposure.

Prescribing in practice

Systemic gentamicin is nephrotoxic and ototoxic, so it requires careful dosing by weight and renal function with therapeutic drug monitoring; cochlear and vestibular damage may be irreversible.
Avoid or use with particular caution in renal impairment, the elderly, and alongside other nephrotoxic or ototoxic agents.
Local gentamicin-loaded cement is generally well tolerated systemically, but document any aminoglycoside allergy before implantation.

Monitoring

For systemic use monitor serum gentamicin levels, renal function and for auditory or vestibular symptoms throughout treatment.

Counselling the patient

Report any hearing changes, ringing in the ears, dizziness or unsteadiness promptly.
Blood tests are needed to keep the systemic dose safe.
Antibiotic-containing cement is part of your joint surgery to help prevent infection.

Evidence & guidelines

MHRA guidance highlights the dose-related nephrotoxic and ototoxic risks of aminoglycosides, supporting therapeutic drug monitoring for systemic use.

Reference: Hartford Nomogram (Aminoglycoside Dosing); NICE NG15; MHRA Ototoxicity Warning; NICE NG124; SPC Cidomycin; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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