Gentamicin 40mg/ml Inj, 2ml
WARNING: This drug may cause kidney, nerve, and hearing problems (like long-lasting hearing loss), even at normal doses. The risk may be higher if you already have kidney or hearing problems, you take higher doses, or you use this drug for a long time. The risk may be higher in older people, infants, or with dehydration. Hearing loss can happen even after this drug is stopped. If you already have kidney problems or hearing problems, tell your doctor. You may need to have hearing and kidney tests.Do not use this drug if you are taking or have recently taken any drugs that can cause nerve, kidney, or hearing problems. This may be drugs like amphotericin B, bacitracin, cephaloridine, cisplatin, colistin, cyclosporine, ethacrynic acid, furosemide, paromomycin, polymyxin B, vancomycin, viomycin, or other drugs like this one. There are many other drugs that can do this. Ask your doctor or pharmacist if you are not sure.Muscle problems (muscle weakness) and severe breathing problems have happened with drugs like this one. The risk is higher in people who already have nerve or muscle problems like myasthenia gravis. The risk is also higher in people who are getting other drugs like those that are used to put you to sleep or to relax muscles. If you have questions, talk with the doctor.This drug may cause harm to the unborn baby if you take it while you are pregnant. If you are pregnant or you get pregnant while taking this drug, call your doctor right away. @ COMMON USES: It is used to treat bacterial infections.
Drug Class
Antibiotic
Pharmacologic Class
Aminoglycoside
Pregnancy Category
Category D
FDA Approved
Jun 1966
DEA Schedule
Not Controlled
Overview
What is this medicine?
Gentamicin is an antibiotic given by injection to treat serious bacterial infections, especially those caused by certain types of bacteria that are difficult to treat. It works by stopping the growth of these bacteria. Because it can have serious side effects, your doctor will monitor you closely with blood tests.
How to Use This Medicine
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take this medication exactly as directed. It can be administered in two ways: as an injection into a muscle or as an infusion into a vein, which is given over a period of time. Unless your doctor advises you to limit your fluid intake, drink plenty of non-caffeinated liquids.
To store this medication at home, consult with your doctor, nurse, or pharmacist for guidance on proper storage. If you miss a dose, contact your doctor for advice on what to do next.
To store this medication at home, consult with your doctor, nurse, or pharmacist for guidance on proper storage. If you miss a dose, contact your doctor for advice on what to do next.
Lifestyle & Tips
- Stay well-hydrated unless otherwise instructed by your doctor.
- Report any changes in hearing (ringing in ears, hearing loss) or balance (dizziness, vertigo) immediately.
- Report any changes in urination (less urine, swelling) immediately.
Available Forms & Alternatives
Available Strengths:
- Gentamicin 0.3% Ophth Soln 5ml
- Gentamicin 0.3% Ophth Solution
- Gentamicin 40mg/ml Inj, 2ml
- Gentamicin 0.1% Cream 15gm
- Gentamicin 40mg/ml Inj, 20ml
- Gentamicin 0.1% Cream 30gm
- Gentamicin Pf Ped 10mg/ml Inj, 2ml
- Gentamicin 0.1% Oint 15gm (topical)
- Gentamicin 0.1% Oint 30gm (topical)
- Gentamicin 80mg/ml Inj, 2ml
Dosing & Administration
Adult Dosing
Standard Dose:
Conventional dosing: 3-5 mg/kg/day IV/IM in 3 divided doses (q8h). Once-daily dosing: 5-7 mg/kg/day IV/IM once daily.
Dose Range:
3 - 7 mg
Condition-Specific Dosing:
severeInfections:
5 mg/kg/day in divided doses or 7 mg/kg/day once daily
urinaryTractInfections:
3 mg/kg/day in divided doses or 5 mg/kg/day once daily
Pediatric Dosing
Neonatal:
Premature or full-term <1 week: 2.5 mg/kg/dose IV/IM q12-24h. Full-term 1 week to 1 month: 2.5 mg/kg/dose IV/IM q8-12h.
Infant:
1 month to <1 year: 2.5 mg/kg/dose IV/IM q8h or 5-7.5 mg/kg/day once daily.
Child:
1 year to <12 years: 2-2.5 mg/kg/dose IV/IM q8h or 5-7.5 mg/kg/day once daily.
Adolescent:
12 years and older: Same as adult dosing.
Dose Adjustments
Renal Impairment:
Mild:
Adjust dosing interval or reduce dose based on creatinine clearance (CrCl). CrCl 60-90 mL/min: q8-12h or reduced dose.
Moderate:
CrCl 30-59 mL/min: q12-24h or further reduced dose.
Severe:
CrCl <30 mL/min: q24-48h or significantly reduced dose. Individualize based on drug levels.
Dialysis:
Hemodialysis: Administer dose after dialysis session. Peritoneal dialysis: Supplementation may be needed. Monitor levels closely.
Hepatic Impairment:
Mild:
No specific dose adjustment required.
Moderate:
No specific dose adjustment required.
Severe:
No specific dose adjustment required. Monitor renal function as hepatic impairment can indirectly affect renal perfusion.
Pharmacology
Mechanism of Action
Gentamicin is an aminoglycoside antibiotic that inhibits bacterial protein synthesis by irreversibly binding to the 30S ribosomal subunit. This binding leads to misreading of the mRNA code, premature termination of protein synthesis, and incorporation of incorrect amino acids, ultimately resulting in the production of non-functional proteins and bacterial cell death.
Pharmacokinetics
Absorption:
Bioavailability:
Not applicable (poor oral absorption, administered IV/IM)
Tmax:
IM: 30-90 minutes; IV: End of infusion
FoodEffect:
Not applicable (parenteral administration)
Distribution:
Vd:
0.2-0.3 L/kg (increases in ascites, edema; decreases in dehydration)
ProteinBinding:
<30%
CnssPenetration:
Limited (increases with inflamed meninges)
Elimination:
HalfLife:
2-4 hours (normal renal function); significantly prolonged in renal impairment
Clearance:
Primarily renal clearance, proportional to creatinine clearance
ExcretionRoute:
Renal (glomerular filtration)
Unchanged:
>90%
Pharmacodynamics
OnsetOfAction:
Rapid (within minutes for IV, 30-60 minutes for IM)
PeakEffect:
Within 30 minutes after IV infusion, 30-90 minutes after IM injection
DurationOfAction:
Dose-dependent, typically allows for q8h or once-daily dosing due to post-antibiotic effect
Safety & Warnings
BLACK BOX WARNING
Aminoglycosides can cause irreversible ototoxicity (vestibular and cochlear) and nephrotoxicity. The risk is greater in patients with impaired renal function, those receiving high doses or prolonged therapy, the elderly, and those receiving concomitant nephrotoxic or ototoxic drugs. Serum concentrations should be monitored to minimize risk. Neuromuscular blockade and respiratory paralysis have been reported, especially after rapid IV administration or in patients with neuromuscular disorders.
Side Effects
Serious Side Effects: Seek Medical Help Immediately
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of kidney problems, including:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Signs of high or low blood pressure, such as:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Dizziness or fainting
Balance problems
Ringing in the ears, hearing loss, or other changes in hearing
Muscle weakness
New or worsening breathing difficulties
Abnormal burning, numbness, or tingling sensations
Twitching
Seizures
Confusion
Extreme fatigue or weakness
Depression
Changes in eyesight
Fever
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Decreased appetite
Weight loss
Headache
Upset stomach or vomiting
Excessive saliva production
Mouth irritation or mouth sores
Hair loss
Joint pain
This is not an exhaustive list of possible side effects. If you have questions or concerns, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of kidney problems, including:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Signs of high or low blood pressure, such as:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Dizziness or fainting
Balance problems
Ringing in the ears, hearing loss, or other changes in hearing
Muscle weakness
New or worsening breathing difficulties
Abnormal burning, numbness, or tingling sensations
Twitching
Seizures
Confusion
Extreme fatigue or weakness
Depression
Changes in eyesight
Fever
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Decreased appetite
Weight loss
Headache
Upset stomach or vomiting
Excessive saliva production
Mouth irritation or mouth sores
Hair loss
Joint pain
This is not an exhaustive list of possible side effects. If you have questions or concerns, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Ringing in the ears (tinnitus)
- Hearing loss
- Dizziness or spinning sensation (vertigo)
- Difficulty with balance or walking
- Decreased urine output
- Swelling in the ankles, feet, or hands
- Muscle weakness or difficulty breathing
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including the symptoms that occurred.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This information will help your doctor and pharmacist assess potential interactions between this medication and other substances you are taking.
* Any existing health problems, as this medication may interact with certain conditions.
To ensure your safety, it is crucial to verify that it is safe to take this medication with all your current medications and health conditions. Do not initiate, discontinue, or modify the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including the symptoms that occurred.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This information will help your doctor and pharmacist assess potential interactions between this medication and other substances you are taking.
* Any existing health problems, as this medication may interact with certain conditions.
To ensure your safety, it is crucial to verify that it is safe to take this medication with all your current medications and health conditions. Do not initiate, discontinue, or modify the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you have a known allergy to sulfites, consult with your doctor, as some formulations of this drug may contain sulfites.
Regular monitoring of your blood work, hearing, and other laboratory tests is crucial, as directed by your doctor. Do not exceed the prescribed duration of treatment, as this may increase the risk of a secondary infection.
If you are 65 years or older, exercise caution when using this medication, as you may be more susceptible to side effects due to age.
If you are breastfeeding, discuss the potential risks to your baby with your doctor to determine the best course of action.
Regular monitoring of your blood work, hearing, and other laboratory tests is crucial, as directed by your doctor. Do not exceed the prescribed duration of treatment, as this may increase the risk of a secondary infection.
If you are 65 years or older, exercise caution when using this medication, as you may be more susceptible to side effects due to age.
If you are breastfeeding, discuss the potential risks to your baby with your doctor to determine the best course of action.
Overdose Information
Overdose Symptoms:
- Severe kidney damage (renal failure)
- Irreversible hearing loss
- Severe dizziness or loss of balance
- Neuromuscular blockade leading to respiratory depression or paralysis
What to Do:
Call 1-800-222-1222 (Poison Control). Treatment is supportive. Hemodialysis may be effective in removing gentamicin from the blood, especially in patients with renal failure. Calcium salts may reverse neuromuscular blockade.
Drug Interactions
Major Interactions
- Nephrotoxic drugs (e.g., amphotericin B, cisplatin, cyclosporine, NSAIDs, vancomycin, loop diuretics like furosemide, polymyxins, tacrolimus): Increased risk of nephrotoxicity.
- Ototoxic drugs (e.g., loop diuretics, ethacrynic acid, cisplatin, vancomycin): Increased risk of ototoxicity.
- Neuromuscular blocking agents (e.g., succinylcholine, rocuronium, vecuronium): Potentiation of neuromuscular blockade, leading to respiratory depression/paralysis.
- Botulinum toxin: Increased risk of neuromuscular blockade.
Moderate Interactions
- Oral anticoagulants (e.g., warfarin): May enhance anticoagulant effect (rare, monitor INR).
- Indomethacin (IV): May increase gentamicin plasma concentrations in neonates.
- Cephalosporins (e.g., cephalothin): Increased risk of nephrotoxicity (controversial, monitor).
Monitoring
Baseline Monitoring
Renal function (serum creatinine, BUN, CrCl)
Rationale: Gentamicin is renally eliminated and nephrotoxic. Baseline assessment is crucial for dosing and monitoring.
Timing: Prior to first dose
Audiometry/Vestibular function
Rationale: Baseline assessment for ototoxicity, especially in patients with pre-existing hearing/balance issues or prolonged therapy.
Timing: Prior to therapy, if prolonged use or high risk
Electrolytes (Potassium, Magnesium, Calcium)
Rationale: Aminoglycosides can cause electrolyte disturbances and are often co-administered with drugs that affect electrolytes.
Timing: Prior to first dose
Routine Monitoring
Serum Gentamicin levels (peak and trough)
Frequency: After 3rd or 4th dose (for multiple daily dosing) or after 1st dose (for once-daily dosing), then as clinically indicated
Target: Conventional: Peak 4-10 mcg/mL, Trough <2 mcg/mL. Once-daily: Peak 16-24 mcg/mL, Trough <1 mcg/mL (or undetectable)
Action Threshold: Levels outside target range require dose adjustment or interval change.
Renal function (serum creatinine, BUN)
Frequency: Daily or every 2-3 days, depending on patient stability and duration of therapy
Target: Stable or improving
Action Threshold: Significant increase in serum creatinine (>0.5 mg/dL or >50% from baseline) may indicate nephrotoxicity and require dose adjustment or discontinuation.
Urine output
Frequency: Daily
Target: >0.5 mL/kg/hr
Action Threshold: Oliguria or anuria may indicate acute kidney injury.
Electrolytes (Potassium, Magnesium, Calcium)
Frequency: Weekly or as clinically indicated
Target: Within normal limits
Action Threshold: Hypokalemia, hypomagnesemia, or hypocalcemia may require supplementation.
Symptom Monitoring
- Hearing loss (tinnitus, high-frequency hearing loss)
- Vertigo, dizziness, ataxia, nystagmus (vestibular toxicity)
- Nausea, vomiting, malaise (signs of toxicity)
- Decreased urine output, swelling (signs of renal impairment)
- Muscle weakness, respiratory depression (signs of neuromuscular blockade)
Special Patient Groups
Pregnancy
Category D. Gentamicin can cause fetal harm when administered to a pregnant woman. Aminoglycosides cross the placenta and have been associated with total, irreversible, bilateral congenital deafness in children whose mothers received streptomycin during pregnancy. While not definitively proven for gentamicin, the risk of ototoxicity to the fetus cannot be excluded.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm, including ototoxicity.
Second Trimester:
Potential for fetal harm, including ototoxicity.
Third Trimester:
Potential for fetal harm, including ototoxicity. Increased risk of accumulation in the fetus due to developing renal function.
Lactation
L3 (Moderately Safe). Gentamicin is excreted into breast milk in small amounts. While systemic absorption by the infant is poor, monitor the infant for diarrhea, candidiasis (thrush, diaper rash), and potential effects on gut flora. The risk of ototoxicity or nephrotoxicity in the infant is considered low but cannot be entirely ruled out.
Infant Risk:
Low risk of systemic effects due to poor oral absorption, but monitor for GI upset or candidiasis.
Pediatric Use
Dosing must be carefully calculated based on weight and age, with close monitoring of serum levels and renal function due to varying pharmacokinetics in different pediatric age groups, especially neonates and infants. Higher risk of toxicity in neonates due to immature renal function.
Geriatric Use
Elderly patients are at increased risk for nephrotoxicity and ototoxicity due to age-related decline in renal function and pre-existing hearing impairment. Dosing should be carefully adjusted based on estimated creatinine clearance, and close monitoring of renal function and drug levels is essential.
Clinical Information
Clinical Pearls
- Gentamicin exhibits concentration-dependent killing and a significant post-antibiotic effect, making once-daily dosing a viable option for many infections, which may also reduce nephrotoxicity.
- Therapeutic drug monitoring (TDM) with peak and trough levels is crucial for optimizing efficacy and minimizing toxicity, especially in patients with fluctuating renal function, severe infections, or prolonged therapy.
- Ensure adequate hydration to minimize the risk of nephrotoxicity.
- Avoid concomitant use with other nephrotoxic or ototoxic drugs whenever possible. If unavoidable, monitor patients extremely closely.
- Gentamicin is often used in combination with beta-lactam antibiotics for synergistic effect against serious Gram-negative infections or for empiric therapy.
Alternative Therapies
- Cephalosporins (e.g., ceftazidime, cefepime)
- Carbapenems (e.g., meropenem, imipenem/cilastatin)
- Fluoroquinolones (e.g., ciprofloxacin, levofloxacin)
- Piperacillin/tazobactam
Cost & Coverage
Average Cost:
Varies widely per 2ml vial
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health problems persist or worsen, it is essential to contact your doctor for further guidance. To ensure safe use, never share your medication with others, and do not take medication prescribed for someone else. Store all medications in a secure location, out of reach of children and pets, to prevent accidental ingestion. Dispose of unused or expired medications properly. Unless instructed to do so by a healthcare professional, do not flush medications down the toilet or drain. If you are unsure about the correct disposal method, consult your pharmacist, who can also inform you about potential drug take-back programs in your area. Some medications may come with an additional patient information leaflet, which your pharmacist can provide. If you have any questions or concerns about your medication, discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication taken, the amount, and the time of ingestion.