Gentamicin (Bacticid) is an aminoglycoside antibiotic that is used to treat a variety of infections of the gastrointestinal, urinary, and pelvic tract. It is also used in the treatment of endocarditis and augment the action of penicillin and vancomycin.

Gentamicin (Garamycin)  Uses:

• Serious infections:

  • Gentamicin is used to treat severe infections caused by susceptible strains of the following microorganisms, including sepsis, meningitis, urinary tract infections, respiratory tract infections, peritonitis, bone infections, skin infections, and soft tissue infections.:
    • P. aeruginosa,
    • Proteus species (indole-positive and indole-negative),
    • Escherichia coli,
    • Klebsiella species,
    • Enterobacter species,
    • Serratia species,
    • Citrobacter species, and
    • Staphylococcus species (coagulase-positive and coagulase-negative).
  • Can be used in conjunction with other antibiotics to treat infective endocarditis brought on by enterococci (see endocarditis treatment guidelines: Infective Endocarditis Treatment Guidelines - AHA/ IDSA)

• Off Label Use of Gentamicin in Adults:

  • Brucellosis
  • Endocarditis, treatment (viridans group streptococcus [VGS] and S. bovis [native or prosthetic valve]) (adults)
  • Uncomplicated Gonococcal infection (patients with severe cephalosporin allergy)
  • Granuloma inguinale (donovanosis)
  • Pelvic inflammatory disease
  • Peritoneal dialysis associated peritonitis
  • Plague, treatment
  • Surgical prophylaxis (preoperative)
  • Tularemia

Gentamicin (Garamycin) Dose in Adults

• Total body weight (TBW) rather than ideal body weight is typically used to calculate the initial mg/kg/dose in individuals who are underweight or nonobese.
• When it comes to persons who are neither underweight nor obese To calculate doses, ideal body weight (IBW) may also be employed.
• Particularly in critically ill patients with serious infections or in disease states known to significantly alter aminoglycoside pharmacokinetics, initial and periodic plasma drug levels (e.g., peak and trough with conventional dosing, the post-dose level at a predetermined time with extended-interval dosing) should be determined (eg, cystic fibrosis, burns, or major surgery).

Gentamicin (Garamycin) Usual dosage ranges:

• Conventional:

  • IM, IV: 3 to 5 mg/kg/day, split into 8 hourly doses

• Once-daily (extended-interval dosing [EID]):

  • IV: One dose per day of 5 to 7 mg/kg.
  • Patients who have ascites, burns that cover more than 20% of their body's surface area, cystic fibrosis, end-stage renal illness (requiring hemodialysis), endocarditis, babies, mycobacterial infections, or are pregnant should not undergo this.

Indication-specific dosing:

Gentamicin (Garamycin) Dose in the treatment of Brucellosis (off-label):

• 5 mg/kg given once daily for 7 days (range: 5 to 14 days).
• Can be given in addition to doxycycline for six weeks.

Gentamicin Dose in the treatment of Cerebrospinal fluid (CSF) shunt infection (as an adjunct to systemic therapy) (off-label route):

• Intraventricular (use a preservative-free preparation):

  • Dose: 4–8 mg per day
  • Depending on the CSF gentamicin concentration (target: 10 to 20 times the MIC of the pathogenic organism), ventricular size, and daily output from the ventricular drain, some experts additionally advise modifying the dosage and administration interval.
  • When ventricular drains are used to give intraventricular gentamicin, the drain should be closed for anywhere between 15 and 60 minutes following administration (allows the solution to equilibrate in CSF).
  • Notably, intraventricular delivery is typically used in patients who fail parenteral therapy despite having the CSF shunt removed or in situations where it cannot be done.

Gentamicin Dose in the treatment of Endocarditis:

• Enterococcus (native or prosthetic valve) (off-label dose):

  • IV, IM: 3 mg/kg/day given in two or three divided doses in addition to a beta-lactam antibiotic or vancomycin.
  • The source of infection and organism sensitivity testing determine the concurrent antibiotic to use and the length of the treatment.

• S.aureus (methicillin-susceptible or methicillin-resistant prosthetic valve) (off-label dose):

  • IV, IM: 2 or 3 divided doses of 3 mg/kg every day for 2 weeks.
  • Can be used with different medications (choice of concomitant antibiotic dependent on organism sensitivity testing)

• Viridans group streptococcus (VGS) and S. bovis (native or prosthetic valve) (off-label):

  • IV, IM: In combination with other antibiotics, 3 mg/kg/day given once daily (preferred) or in three evenly spaced doses (alternative) (choice of concomitant antibiotic and treatment duration are dependent on organism sensitivity testing and source of infection)

Gentamicin Dose in the treatment of uncomplicated Gonococcal infection in patients with severe cephalosporin allergy (off-label):

• IM: Combined with 240 mg of oral azithromycin in a single dose.

Gentamicin Dose in the treatment of Granuloma inguinale (donovanosis) (off-label):

• IV: 8 hourly doses of 1 mg/kg.
• If an improvement is not noticeable during the first few days of treatment, gentamicin must be added to the advised antibiotic drug.

Gentamicin Dose in the treatment of Bacterial Meningitis (caused by Enterococcus spp, Listeria monocytogenes, Streptococcus agalactiae, or Pseudomonas aeruginosa):

• IV: Split doses of 5 mg/kg per day given every 8 hours (administered with other antimicrobials [varies by a causative organism and susceptibility]).

Gentamicin Dose in the treatment of Intra-abdominal infections (off-label dose):

• IV: One dose of 5–7 mg/kg each day for 4–7 days (unless it is difficult to achieve source control).

Gentamicin Dose in the treatment of Pelvic inflammatory disease (off-label):

• Loading dose:

  • A dose of 2 mg/kg IV or IM, followed by 1.5 mg/kg IV every eight hours, or a dose of 3 to 5 mg/kg IV once day in conjunction with clindamycin IV.
  • Transition from parenteral to oral therapy can typically begin within 24 to 48 hours of clinical improvement for complete treatment.

Gentamicin Dose in the treatment of Peritoneal dialysis-associated peritonitis (off-label):

Intraperitoneal:

• Intermittent dosing:

  • 6 mg/kg per exchange, once daily, with a six-hour dwell time

• Continuous dosing (all exchanges):

  • Loading dose: 8 mg per L.
  • Maintenance dose: 4 mg per L

Gentamicin Dose in the treatment of Plague (Yersinia pestis) (off-label):

• IM, IV: The duration of therapy is 10 to 14 days, or until two days after the patient is afebrile. The dosage options include 5 mg/kg/dose once day or a 2 mg/kg loading dose followed by 1.7 mg/kg/dose eight hours apart.

Gentamicin Dose in the treatment of hospital-acquired, or ventilator-associated pneumonia (off-label):

• IV: Depending on the rate of clinical improvement, shorter or longer durations may be considered (5–7 mg/kg/day, once daily for 7 days).
  When used as empiric therapy, combine with a S. aureus-active medication and an additional antipseudomonal medication.

Note:  Aminoglycosides are not advised for use as monotherapy in patients with ventilator-associated pneumonia or hospital-acquired pneumonia caused by P. aeruginosa.

Gentamicin Dose in the treatment of Sepsis/septic shock (empiric or targeted therapy) (off-label):

• IV: 5–7 mg/kg taken once day.
• If possible, the initial dose should be given within an hour of the diagnosis of sepsis or septic shock.
• For serious infections, a course of medication lasting 7 to 10 days is usually sufficient.
• The ideal length of therapy depends on a number of variables; an infectious diseases consultation may be required.

Gentamicin (Garamycin) Dose in preoperative Surgical prophylaxis (off-label):

• IV: 5 mg/kg, with or without additional antibiotics, within 60 minutes of the surgical incision (procedure dependent).

Note: Unless a person is >20% over their ideal body weight, dosage is dependent on their actual body weight. In such case, it is recommended to estimate their dosage needs using the formula IBW + 0.4 (TBW - IBW) (Bratzler 2013)

Gentamicin Dose in the treatment of Synergy (for gram-positive infections):

• IM, IV: 3 mg/kg/day given in 1-3 separate doses (with ampicillin)

Gentamicin Dose in the treatment of Tularemia (off-label):

• IM, IV: 10 days at a dose of 5 mg/kg once daily OR 10 days at a dose of 5 mg/kg twice daily.

Gentamicin Dose as an alternative agent in the treatment of complicated Urinary tract infection, (including pyelonephritis):

• Outpatients:

  • IV, IM: 5 mg/kg once, followed by suitable oral therapy for 5–14 days.

Note:

• When fluoroquinolones or beta-lactams cannot be used due to allergy, intolerance, unavoidable medication interactions, or resistance, can be utilised as a substitute parenteral agent.

Gentamicin (Garamycin) Dose in Children

Note:

• Based on an assessment of the appropriate body weight, the dosage should be determined.
• It is recommended to estimate the dosage requirement for morbidly obese children, adolescents, and adults using a dosing weight of IBW + 0.4 (TBW - IBW).
• Initial dose advice is given; dosage should be modified depending on observation of serum levels.
• Particularly in critically ill patients with serious infections or in disease states known to significantly alter aminoglycoside pharmacokinetics, initial and periodic plasma drug concentrations (e.g., peak and trough with conventional dosing, the post-dose level at a predetermined time with extended-interval dosing) should be determined (eg, cystic fibrosis, burns, or major surgery).

Gentamicin General dosing for susceptible infection:

Note:

• Patients using ECMO have no recognised optimal dose or frequency;
• Extrapolating pharmacokinetic data and dosing to all patients getting ECMO is challenging due to patient-specific factors (such as the ECMO procedure's unpredictability) and patient-specific considerations (such as the ECMO's rationale);
• Determine each patient's unique dose requirements while closely monitoring serum concentrations.

• Conventional dosing:

  • Infants, Children, and Adolescents:

    • IM, IV: 2-4 mg/kg/dose given every 8 hours;
    • Some paediatric patients, such as those undergoing continuous hemofiltration, those with severe burns, and febrile granulocytopenic patients, may require higher doses; in these cases, the dose should be changed in accordance with the patient's unique needs as determined by renal function, serum drug concentrations, and patient-specific clinical parameters.

• Extended-interval dosing: Limited data available:

  • Weight-directed:

    • Infants, Children, and Adolescents:
      • IV: Every 24 hours in patients with normal renal function, 4.5 to 7.5 mg/kg/dose.
  • Age-directed:
    • Infants and Children ≥3 months to <2 years:
      • IV: 9.5 mg per kg per dose every day
    • Children 2 to <8 years:
      • IV: 8.5 mg per kg per dose every day
    • Children ≥8 years and Adolescents:
      • IV: 7 mg per kg per dose every day

Gentamicin (Garamycin) Dose in the treatment of CNS infection:

• Meningitis (IDSA):

  • Infants and Children:
    • IV: 7.5 mg per kg per day every 8 hours in divided doses
  • Adolescents:
    • IV: 5 mg per kg per day divided every 8 hours in divided doses

• VP-shunt infection, ventriculitis, including healthcare-associated:

  • Limited data 
  • No optimal dose is established
  • Intraventricular/intrathecal (use a preservative-free preparation):
    • Infants and Children: 1 to 2 mg per day
    • Adolescents: No dosage guidelines have been given, but it has been advised that adults take 4 to 8 mg per day.

Gentamicin Dose in the treatment of Cystic fibrosis, pulmonary infection:

• Infants, Children, and Adolescents:

  • Conventional dosing:
    • IM, IV: 3.3 mg per kg per dose 8 hourly.
  • Extended-interval dosing:
    • IV: 10 to 12 mg per kg per dose every 24 hours.
  • Note: Extended-interval dosing is advised by the CF Foundation as being preferable to traditional dose.

Gentamicin (Garamycin) Dose in the treatment of Endocarditis:

• Synergy dosing:

  • Children and Adolescents:

    • IV: In conjunction with other antibiotics, administer 3 to 6 mg/kg/day divided every 8 hours; adjust the dose to produce a target peak concentration of 3 to 4 mcg/mL and trough concentration of 1 mcg/mL.

• Staphylococcus aureus (methicillin-resistant), prosthetic valve/material:

  • Infants, Children, and Adolescents:

    • IV: In addition to vancomycin and rifampicin, the dosage is 3 mg/kg/day distributed every 8 hours.

• Treatment dose (eg, gram-negative organisms):

  • Children and Adolescents:

    • IV: Aim for a target peak concentration of 5 to 10 mcg/ml and a trough concentration of 1 to 1.5 mcg/ml with a dose of 7.5 mg/kg/day divided every 8 hours.

Gentamicin Dose in the treatment of complicated Intra-abdominal infection:

• Infants, Children, and Adolescents:

  • IV: Every 8 to 24 hours, 3 to 7.5 mg/kg/day is administered.

Gentamicin (Garamycin) Dose in the treatment of Peritonitis (peritoneal dialysis):

• Infants, Children, and Adolescents:

  • Intermittent: Intraperitoneal:

    • 0.6 mg/kg/dose every 24 hours for anurics during the prolonged stay
    • In the extended stay, nonanuric: 0.75 mg/kg/dose every 24 hours

  • Continuous: Intraperitoneal:

    • 8 mg per litre of dialysate is the loading dose.
    • Dosage for maintenance: 4 mg per litre

Gentamicin (Garamycin) Dose for Surgical prophylaxis:

• Infants, Children, and Adolescents:

  • IV: As a single dose of 2 to 2.5 mg/kg; normally recommended amount for children and adolescents is 2.5 mg/kg.
  • provide with or without additional antibiotics within 60 minutes after making a surgical incision (procedure dependent).

Gentamicin (Garamycin) Dose in the treatment of UTI:

• Extended-interval dosing:
  • The following age-directed dose has been recommended based on data from 90 patients (ages: 1 month to 12 years):
  • Infants and Children <5 years:
    • IV: 7.5 mg per kg per dose every 24 hours
  • Children 5 to 10 years:
    • IV: 6 mg per kg per dose every 24 hours
  • Children 11 to 12 years:
    • IV: 4.5 mg per kg per dose every 24 hours

Gentamicin Pregnancy Risk Factor D

• Aminoglycosides can harm a foetus if given to pregnant women. [US Boxed Warning]
• Multiple reports have indicated that children born to mothers who received an aminoglycoside (streptomycin), during pregnancy may be at risk of bilateral congenital hearing loss.
• There is still a chance of harm even if there haven't been any reports of serious negative effects on the child or foetus following maternal usage of all aminoglycosides.
• Some pharmacokinetic parameters for gentamicin could be affected by pregnancy-induced physiological changes
• Acute pyelonephritis is one of the infections that has been examined for the treatment and prevention of in pregnant women with Gentamicin.

Gentamicin use during breastfeeding:

• Breast milk contains gentamicin (Celiloglu 1994).
• By taking the greatest content of breast milk and comparing it to an infant therapeutic dosage of 7.5 mg/kg/day, the relative infant dose (RID) of gentamicin is determined.
• If the RID of a medication exceeds 10%, breastfeeding is acceptable.
• The milk level of 0.78 mg/mL was used to calculate the RID of Gentamicin. As a result, a daily newborn dose of 0.117 mg/kg/day via breastfeeding is estimated.
• After 5 days of maternal administration of gentamicin 80 mg IM 3 times per day, this milk concentration was determined.
• Any antibiotic exposure can cause a modification of the bowel flora.
• According to the World Health Organization (WHO), gentamicin is compatible with breastfeeding. It is important to monitor infants for thrush or diarrhea.

Gentamicin (Garamycin) Dose in Kidney disease:

• Conventional dosing:

  • Manufacturer’s labeling:

    • Administer usual dosage for initial dose, then estimate reduced dose by dividing initial dose by patient’s serum creatinine level (in mg/dL) and administer 8 hourly (eg, a 60 kg patient with serum creatinine of 2 mg/dL at a dose of 1 mg/kg would receive an initial dose of 60 mg, followed by 30 mg every 8 hours)

  • Alternate dosing (Aronoff 2007):

    • Note: Recommendations for renally adjusted dosages are based on doses of 1.7 mg/kg/dose every eight hours or 5–7 mg/kg/dose once day.
    • GFR >50 mL/minute:
      • ]Dosage adjustment not required. 
    • GFR 10 to 50 mL/minute:
      • Take every 12 to 48 hours
    • GFR <10 mL/minute:
      • Take every 48 to 72 hours

  • Once-daily (extended-interval dosing [EID]):

    • Note:
      • Base initial dosing interval on the following; adjust interval based on serum levels using institution-specific policies.
    • CrCl ≥60 mL/minute:
      • Take every 24 hours
    • CrCl 40 to 59 mL/minute:
      • Take every 36 hours
    • CrCl 20 to 39 mL/minute:
      • Take every 48 hours
    • CrCl <20 mL/minute:
      • Monitor serum levels and use conventional dosing or re-dose when gentamicin level is less than 1 mcg/mL.
  • Note:
    • In patients with sepsis/septic shock and significant renal impairment, the SSC recommendations do not advocate once-daily dosage.
    • Patients should continue to receive once-daily dose with a prolonged interval even if they have modest renal impairment (ie, up to 3 days).

  • Intermittent hemodialysis (IHD) (administer after hemodialysis on dialysis days):

    • Dialyzable (~50%; variable; dependent on filter, duration, and type of IHD):
    • 2 to 3 mg/kg of the loading dose is administered first, and afterwards:
      • Mild UTI or synergy:
        • Every 48 to 72 hours, 1 mg/kg/dose; redose if preHD or post-HD concentrations are less than 1 mg/L
      • Moderate-to-severe UTI:
        • Consider redosing for pre-HD concentrations of 1.5 to 2 mg/L or post-HD values of 1 mg/L. 1 to 1.5 mg/kg/dose every 48 to 72 hours
      • Systemic gram-negative rod infection:
        • Consider redosing for pre-HD concentrations of less than 3 to 5 mg/L or post-HD amounts of less than 2 mg/L.
    • Note: Dosing is based on the premise that IHD sessions are complete three times a week.

  • Continuous renal replacement therapy (CRRT):

    • The technique of renal replacement, the type of filter, and the flow rate all have a significant impact on drug clearance.
    • Close observation of the pharmacologic response, warning indicators of drug accumulation-related side effects, and target drug concentrations are necessary for proper dosing (if appropriate).
    • Note:
      • The following suggestions should not replace clinical judgement and are simply general advice (based on dialysate flow/ultrafiltration rates of 1 to 2 L/hour and limited residual renal function):

    • CVVH/CVVHD/CVVHDF:

      • Mild UTI or synergy:
        • 1 mg/kg every 24 to 36 hours after a loading dose of 2 to 3 mg/kg/dose (redose when concentration is less than 1 mg/L).
      • Moderate to severe UTI:
        • 1 to 1.5 mg/kg every 24 to 36 hours (redose when concentration 1.5 to 2 mg/L) after a loading dose of 2 to 3 mg/kg/dose.
      • Systemic gram-negative infection:
        • 1.5 to 2.5 mg/kg every 24 to 48 hours (usually accepted to re-dose when concentration 2 mg/L) after a loading dose of 2 to 3 mg/kg/dose.

Gentamicin (Garamycin) Dose in Liver disease:

Gentamicin does not undergo hepatic metabolism that's why dosage adjustment is not likely to be necessary and no dosage adjustments provided in the manufacturer’s labeling.

Side effects of Gentamicin (Garamycin):

• Cardiovascular:

  • Edema
  • Hypertension
  • Hypotension
  • Phlebitis
  • Thrombophlebitis

• Central Nervous System:

  • Abnormal Gait
  • Ataxia
  • Brain Disease
  • Confusion
  • Depression
  • Dizziness
  • Drowsiness
  • Headache
  • Lethargy
  • Myasthenia
  • Numbness
  • Paresthesia
  • Peripheral Neuropathy
  • Pseudomotor Cerebri
  • Seizure
  • Vertigo

• Dermatologic:

  • Alopecia
  • Erythema
  • Pruritus
  • Skin Rash
  • Urticaria

• Endocrine & Metabolic:

  • Hypocalcemia
  • Hypokalemia
  • Hypomagnesemia
  • Hyponatremia
  • Weight Loss

• Gastrointestinal:

  • Anorexia
  • Clostridioides (Formerly Clostridium) Difficile-Associated Diarrhea
  • Decreased Appetite
  • Enterocolitis
  • Nausea
  • Sialorrhea
  • Stomatitis
  • Vomiting

• Genitourinary:

  • Casts In Urine (Hyaline
  • Granular)
  • Fanconi-Like Syndrome (Infants And Adults; High Dose
  • Prolonged Course)
  • Oliguria
  • Proteinuria

• Hematologic & Oncologic:

  • Agranulocytosis
  • Anemia
  • Eosinophilia
  • Granulocytopenia
  • Leukopenia
  • Purpura
  • Reticulocytopenia
  • Reticulocytosis
  • Splenomegaly
  • Thrombocytopenia

• Hepatic:

  • Hepatomegaly
  • Increased Liver Enzymes

• Hypersensitivity:

  • Anaphylaxis
  • Anaphylactoid Reaction
  • Hypersensitivity Reaction

• Local:

  • Injection Site Reaction
  • Pain At Injection Site

• Neuromuscular & Skeletal:

  • Arthralgia
  • Muscle Cramps
  • Muscle Fatigue (Myasthenia Gravis-Like Syndrome)
  • Muscle Twitching
  • Tremor
  • Weakness

• Ophthalmic:

  • Visual Disturbance

• Otic:

  • Auditory Impairment
  • Hearing Loss (Associated With Persistently Increased Serum Concentrations; Early Toxicity Usually Affects High-Pitched Sound)
  • Tinnitus

• Renal:

  • Decreased Creatinine Clearance
  • Decreased Urine Specific Gravity
  • Increased Blood Urea Nitrogen
  • Increased Serum Creatinine
  • Polyuria
  • Renal Failure (High Trough Serum Concentrations)
  • Renal Tubular Necrosis

• Respiratory:

  • Dyspnea
  • Laryngeal Edema
  • Pulmonary Fibrosis
  • Respiratory Depression

• Miscellaneous:

  • Fever

Contraindications to Gentamicin (Garamycin):

Hypersensitivity to gentamicin or any component of this formulation.

Warnings and precautions

• Hypersensitivity

  • It is possible to cross-sensitive to other aminoglycosides.

• Nephrotoxicity: [US Boxed Warning]

  • May cause nephrotoxicityConcomitant nephrotoxic medication, preexisting renal impairment and advanced age are all risk factors.
  • If you notice signs of nephrotoxicity, discontinue treatment. Renal damage can usually be reversed.

• Paralysis and neuromuscular blockade

  • Can cause respiratory paralysis and neuromuscular blockade, especially if given too soon after anesthesia.

• Neurotoxicity: [US Boxed Warn]

  • May cause neurotoxicityPreexisting renal impairment, concomitant neurotoxic medication, advanced age, and dehydration are all risk factors.
  • The amount and duration of treatment will determine the degree of ototoxicity.
  • Tinnitus and vertigo may indicate bilateral permanent damage to the ears or vestibular injury.
  • Treatment should be stopped if ototoxicity symptoms appear.

• Superinfection

  • Extended use can result in superimposed bacterial and fungal illnesses like pseudomembranous collitis or diarrhoea caused by Clostridium difficile. Most frequently, CDAD has been observed more than two months after antibiotic therapy.

• An abnormality in the electrolyte:

  • Patients with hypocalcemia, hypokalemia, and hypomagnesemia should be cautious.

• Hearing impairment:

  • Patients with vertigo, hearing loss, or tinnitus should be cautious.

• Neuromuscular disorders:

  • Patients with neuromuscular conditions, such as myasthenia gravis, need to exercise caution.

• Renal impairment

  • Patients with pre-existing renal impairment should be cautious; dosage modifications may be necessary.

Gentamicin: Drug Interaction

Risk Factor C (Monitor therapy)
Amphotericin B	Aminoglycosides' nephrotoxic effects might be amplified.
Arbekacin	Aminoglycosides' nephrotoxic effects might be amplified. Arbekacin may make aminoglycosides more ototoxic.
BCG Vaccine (Immunization)	Antibiotics may reduce the BCG vaccine's therapeutic effect (Immunization).
Bisphosphonate Derivatives	The hypocalcemic action of bisphosphonate derivatives may be enhanced by aminoglycosides.
Botulinum Toxin-Containing Products	The neuromuscularblocking action of products containing botulinum toxin may be enhanced by aminoglycosides.
Capreomycin	Aminoglycosides' capacity to inhibit neuromuscular transmission might be increased.
CARBOplatin	Aminoglycosides may increase CARBOplatin's ototoxic effects. especially when carboplatin doses are higher.
Cardiac Glycosides	Cardiac Glycosides' serum levels may be lowered by aminoglycosides. Only oral aminoglycoside treatment has proven to have this effect.
Cefazedone	Aminoglycosides' nephrotoxic effects might be amplified.
Cephalosporins (2nd Generation)	Aminoglycosides' nephrotoxic effects might be amplified.
Cephalosporins (3rd Generation)	Aminoglycosides' nephrotoxic effects might be amplified.
Cephalosporins (4th Generation)	Aminoglycosides' nephrotoxic effects might be amplified.
Cephalothin	Aminoglycosides' nephrotoxic effects might be amplified.
Cephradine	Aminoglycosides' nephrotoxic effects might be amplified.
CISplatin	Aminoglycosides' nephrotoxic effects might be amplified.
CycloSPORINE (Systemic)	Aminoglycosides may increase CycloSPORINE's nephrotoxic effects (Systemic).
Distigmine	Aminoglycosides may reduce Distigmine's therapeutic efficacy.
Lactobacillus and Estriol	The therapeutic effects of Lactobacillus and Estriol may be reduced by antibiotics.
Loop Diuretics	Aminoglycosides' harmful or poisonous effects could be amplified. ototoxicity and nephrotoxicity in particular.
Neuromuscular-Blocking Agents	Neuromuscular-Blocking Agents' respiratory depressive action may be strengthened by aminoglycosides.
Nonsteroidal Anti-Inflammatory Agents	Aminoglycosides' excretion may be reduced. only information on preterm newborns.
Oxatomide	Aminoglycosides' nephrotoxic effects might be amplified.
Tenofovir Products	Tenofovir products' serum concentration may be raised by aminoglycosides. Aminoglycoside content in the serum may rise as a result of using tenofovir products.
Vancomycin	Aminoglycosides' nephrotoxic effects might be amplified.
Risk Factor D (Consider therapy modification)
Colistimethate	Colistimethate's nephrotoxic action may be increased by aminoglycosides. Colistimethate's ability to suppress neuromuscular activity may be improved by aminoglycosides.
Penicillins	Aminoglycosides' serum levels could drop. mainly found in patients with renal impairment and extended spectrum penicillins. Penicillin G (Parenteral/Aqueous); Penicillin G Benzathine; Penicillin G Procaine; Penicillin V Benzathine; Penicillin V Potassium; are exceptions to this rule. Other exceptions are Amoxicillin, Ampicillin, Bacampicillin, Cloxacillin, Dicloxacillin, Nafcillin, and Oxacillin.
Sodium Picosulfate	Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic.
Typhoid Vaccine	Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 3 days after cessation of antibacterial agents.
Risk Factor X (Avoid combination)
Agalsidase Alfa	Gentamicin (Systemic) may lessen Agalsidase Alfa's therapeutic impact.
Agalsidase Beta	Gentamicin (Systemic) may lessen Agalsidase Alfa's therapeutic impact.
Ataluren	Aminoglycosides' harmful or poisonous effects could be amplified. Specifically, using ataluren and aminoglycosides simultaneously may result in an elevated risk of nephrotoxicity.
BCG (Intravesical)	Antibiotics may lessen BCG's therapeutic effects (Intravesical).
Cholera Vaccine	The therapeutic benefit of the cholera vaccine may be reduced by antibiotic use. Management: Cholera vaccine should not be administered to individuals taking systemic antibiotics or within 14 days after taking oral or parenteral antibiotics.
Foscarnet	Aminoglycosides' nephrotoxic effects might be amplified.
Mannitol (Systemic)	Aminoglycosides' nephrotoxic effects might be amplified.
Mecamylamine	Mecamylamine's ability to suppress neuromuscular activity may be improved by aminoglycosides.
Methoxyflurane	Methoxyflurane's nephrotoxic effects may be intensified by aminoglycosides.

 

Monitoring parameters:

• Plasma levels of gentamicin, urine output, BUN, serum creatinine, and urine analysis (as appropriate to dosing method).
• In standard dosage, levels are normally measured before and after the third dose.
• Hearing should be evaluated before, during, and after treatment for those who are at risk for ototoxicity or who will be on long-term therapy (>2 weeks).
• In vitro, several penicillin derivatives may hasten the breakdown of aminoglycosides.
• This may have clinical implications for individuals receiving specific penicillin (ticarcillin, piperacillin, carbenicillin) and aminoglycoside (gentamicin, tobramycin) combination therapies. It is necessary to closely monitor aminoglycoside concentrations.

How to administer Gentamicin (Garamycin)?

IM:

• If at all possible, administer via deep IM route.

IV:

• Over a period of 30 to 120 minutes. It has been demonstrated in vitro that several penicillins, including carbenicillin, ticarcillin, and piperacillin, inactivate aminoglycosides.
• Tobramycin and gentamicin have exhibited this to a larger extent, although amikacin has demonstrated more stability against inactivation.
• Concurrent use of these medications raises the possibility of decreased in vivo antibacterial efficacy, especially in cases of severe renal impairment.
• However, there is a lack of unambiguous clinical proof.
• If combination penicillin/aminoglycoside therapy is needed in patients with renal impairment, dosage separation (if practical) and regular monitoring of aminoglycoside levels, CBC, and clinical response should be taken into consideration.

Intraventricular (off-label route):

• When a ventricular drain is used, the drain should be clamped for 15 to 60 minutes before being opened to allow the gentamicin solution to equilibrate in the cerebrospinal fluid.
• Must use preservative-free preparations only.

Mechanism of action of Gentamicin (Garamycin):

• via attaching to the 30S ribosomal protein subunit, interferes with the synthesis of bacterial proteins, impairing the cell membrane.

Absorption: Distribution:

• Intramuscular: Complete and rapid;
• Oral: Lowly absorbed (1%).
• • Primarily into extracellular liquid (highly hydrophilic);
  • High concentrations in the renal cortex
  • The intravenous route allows for minimal penetration of CSF and ocular tissue.

• CSF:blood level ratio:
  • Normal meninges: <10%;
  • Inflamed meninges: ≤25%

Protein binding:

• <30%

Half-life elimination:

• Neonates: <1 week: 3 to 11.5 hours; 1 week to 1 month: 3 to 6 hours
• Infants: 4 ± 1 hour
• Children: 2 ± 1 hour
• Adolescents: 1.5 ± 1 hour
• Adults: ~2 hours
  • Renal failure: mean: 41 ± 24 hours; Range: 6 to 127 hours

Time to peak serum concentrations:

• IM: 30 to 90 minutes.
• IV: 30 minutes after a 30-minute infusion.

Note: Distribution may be prolonged after larger doses. Excretion:

• Urine (≥70% as unchanged drug)

Clearance:

• Directly related to renal function
  • Neonates: 0.045 ± 0.01 L/hour/kg
  • Infants: 0.1 ± 0.05 L/hour/kg
  • Children: 0.1 ± 0.03 L/hour/kg
  • Adolescents: 0.09 ± 0.03 L/hour/kg

International Brand Names of Gentamicin:

• Agentam
• Alcomicin
• Apigent
• Azupel
• Bacticid
• Balticin
• Biogaracin
• Cidomycin
• Diakarmon
• Duracoll
• Epigent
• Ethigent
• Evozar
• Gamicin
• Gantalyn
• Garalone
• Garamicin
• Garamicina
• Garamycin
• Garasent
• Garasone
• Garaxil
• Gem
• Gemycin
• Genacin
• Genbexil
• Genmisil
• Genoptic
• Gensumycin
• Genta-590
• Gentabiotic
• Gentabrand
• Gentac
• Gentacare
• Gentaderm
• Gentagram
• Gental
• Gentalline
• Gentalyn
• Gentam
• Gentamax
• Gentamed
• Gentamen
• Gentamina
• Gentamytrex
• Gentapro
• Gentarad
• Gentasil
• Gentasporin
• Gentatrim
• Gentawin
• Genticin
• Genticyn
• Gentocil
• Hexamycin
• Ikagen
• Intagenta
• Jie Li Tai
• Lacromycin
• Lyramycin
• Maxigen
• Miragenta
• Miramycin
• Mycin
• Nelgen
• Obogen
• Ophtagram
• Optimycin
• Provisual
• Qutacin
• Refobacin
• Rigaminol
• Rocy Gen
• Rovixida
• Rupegen
• Servigenta
• Sulmycin
• Versigen
• Vijomicin

Gentamicin Brand Names in Pakistan:

Gentamicin Injection 80 Mg
Genxat	Surge Laboratories (Pvt) Ltd.

 

Gentamicin Injection 5 Mg/Ml
Gentic	Bosch Pharmaceuticals (Pvt) Ltd.
Genticyn Paed	Ray Pharma (Pvt) Ltd

 

Gentamicin Injection 10 Mg/Ml
Cidomycin	Sanofi Aventis (Pakistan) Ltd.
Cidomycin	Sanofi Aventis (Pakistan) Ltd.
Fortis	Saffron Pharmaceutical Company
Genacin	Macter International (Pvt) Ltd.
Gentageof 10%	Geofman Pharmaceuticals
Gentapath	Lahore Chemical & Pharmaceutical Works (Pvt) Ltd
Genticillin	Indus Pharma (Pvt) Ltd.
Lirin	Zinta Pharmaceuticals Industries
Mygent	Rex Pharmaceuticals Pakistan
Refobacin	Merck Private Ltd.
Sg	Saydon Pharmaceutical Industries (Pvt) Ltd.
Sudocin	Trigon Pharmaceuticals Pakistan (Pvt) Ltd.

 

Gentamicin Injection 20 Mg/Ml
Genacin	Macter International (Pvt) Ltd.
Gentasone	Helix Pharma (Private) Limited
Gentic	Bosch Pharmaceuticals (Pvt) Ltd.
Genzy	Akson Pharmaceuticals (Pvt) Ltd.
Mygent	Rex Pharmaceuticals Pakistan
Refobacin	Merck Private Ltd.
Sg	Saydon Pharmaceutical Industries (Pvt) Ltd.
Skycin	Karachi Pharmaceutical Laboratory
Sudocin	Trigon Pharmaceuticals Pakistan (Pvt) Ltd.

 

Gentamicin Injection 40 Mg/Ml
B-Genta	Wellborne Pharmachem And Biologicals
Cidomycin	Sanofi Aventis (Pakistan) Ltd.
Cidomycin	Sanofi Aventis (Pakistan) Ltd.
Elkogent	Elko Organization (Pvt) Ltd.
Ephagent	Epharm Laboratories
Ephagent	Epharm Laboratories
Fortis	Saffron Pharmaceutical Company
Fortis	Saffron Pharmaceutical Company
Genacin	Macter International (Pvt) Ltd.
Gencyn	Harmann Pharmaceutical Laboratories (Pvt) Ltd.
Genom	Geofman Pharmaceuticals
Genom	Geofman Pharmaceuticals
Gentalek	Novartis Pharma (Pak) Ltd
Gentamark	Welmark Pharmaceuticals
Gentamicin	Lahore Chemical & Pharmaceutical Works (Pvt) Ltd
Gentamicin	Lahore Chemical & Pharmaceutical Works (Pvt) Ltd
Gentamycin	Lawrence Pharma
Gentamycin	Orient Laboratories
Gentamycin	Orient Laboratories
Gentamycin	Venus Pharma
Gentamycin	Amros Pharmaceuticals.
Gentamycin	Amros Pharmaceuticals.
Gentamycin	Amros Pharmaceuticals.
Gentamycin	Venus Pharma
Gentamycin	Venus Pharma
Gentaquin	Global Pharmaceuticals
Gentasone	Helix Pharma (Private) Limited
Gentasone	Helix Pharma (Private) Limited
Gentax	Drugs Inn Pakistan
Gentic	Bosch Pharmaceuticals (Pvt) Ltd.
Genticillin	Indus Pharma (Pvt) Ltd.
Genticillin	Indus Pharma (Pvt) Ltd.
Genticyn	Ray Pharma (Pvt) Ltd
Genticyn	Ray Pharma (Pvt) Ltd
Genzy	Akson Pharmaceuticals (Pvt) Ltd.
Lirin	Zinta Pharmaceuticals Industries
Mygent	Rex Pharmaceuticals Pakistan
Polygenta	Polyfine Chempharma (Pvt) Ltd.
Polygenta	Polyfine Chempharma (Pvt) Ltd.
Refobacin	Merck Private Ltd.
Refobacin	Merck Private Ltd.
Sepcin	Elko Organization (Pvt) Ltd.
Sg	Saydon Pharmaceutical Industries (Pvt) Ltd.
Spegecin	Spencer Pharma

 

Gentamicin Injection 50 Mg/Ml
Gentageof 5%	Geofman Pharmaceuticals
Gentamycin	Amros Pharmaceuticals.

 

Gentamicin Injection 80 Mg/Ml
Cidomycin	Sanofi Aventis (Pakistan) Ltd.
Genta	Epoch Pharmaceutical
Genta	Epoch Pharmaceutical
Gentacil	Star Laboratories (Pvt) Ltd.
Gentacil	Star Laboratories (Pvt) Ltd.
Gentamycin	Amros Pharmaceuticals.
Mygent	Rex Pharmaceuticals Pakistan
Skycin	Karachi Pharmaceutical Laboratory

 

Gentamicin Drops 300 Mg/Ml
Ephagent	Epharm Laboratories

 

Gentamicin Eye Drops 0.3 % W/V
G-Mycin	Mass Pharma (Private) Limited
G-Optin	Festel Lab
Genek	Innvotek Pharmaceuticals
Genteal	Novartis Pharma (Pak) Ltd
Genticol	Neo Medix
Genticyn	Ray Pharma (Pvt) Ltd
Medigentacin	Medipak Limited
Mygent	Rex Pharmaceuticals Pakistan
Optagen	Remington Pharmaceutical Industries (Pvt) Ltd.
Polygenta	Polyfine Chempharma (Pvt) Ltd.
V-Genta	Vega Pharmaceuticals Ltd.

 

Gentamicin Eye Drops 3.5 %W/V
Genicol -Eye Drops	Reko Pharmacal (Pvt) Ltd.

 

Gentamicin Ear Drops 0.3 % W/V
Otogen	Remington Pharmaceutical Industries (Pvt) Ltd.

 

Gentamicin Eye Oint 0.3 % W/W
Genticol	Neo Medix

 

Gentamicin E And E Drops 0.3 % V/V
Gentabact	Nabiqasim Industries (Pvt) Ltd.

 

Gentamicin E And E Drops 0.3 % W/V
Gefcin Eye/Ear	Multinational Buisness Link
Genta	Epoch Pharmaceutical
Gentamicin	Lahore Chemical & Pharmaceutical Works (Pvt) Ltd
Gentamycin	Amros Pharmaceuticals.
Gentamycin	Mehran Traders
Gentamycin	Amros Pharmaceuticals.

 

Gentamicin Oint 0.1 %
Beclic G	Aims Traders

 

Gentamicin Cream 1 % W/W
Primagent	Prime Labs. (Pvt) Ltd.

 

Gentamicin Cream 0.1 % W/W
Atcogen 0.1%	Atco Laboratories Limited
Gentanix	Biogen Pharma
H-Neugenta	Neutro Pharma (Pvt) Ltd.
Isgent	Isis Pharmaceutical
Mecona	Valor Pharmaceuticals

 

Gentamicin Cream 0.3 % W/W
Gentamycin	Krka-Pak Pharmaceutical & Chemical Works
Genticyn	Ray Pharma (Pvt) Ltd
Swigen	Swiss Pharmaceuticals (Pvt) Ltd.

 

Gentamicin Eye Gel 0.3 % W/W
Genteal	Novartis Pharma (Pak) Ltd