Unasyn 3gm Inj 1 Vial
It is used to treat bacterial infections.
Drug Class
Antibiotic, Beta-lactamase inhibitor combination
Pharmacologic Class
Penicillins, Beta-lactamase inhibitors
Pregnancy Category
Category B
FDA Approved
Sep 1986
DEA Schedule
Not Controlled
Overview
What is this medicine?
Unasyn is an antibiotic medication given by injection to treat various bacterial infections. It contains two active ingredients: ampicillin, which kills bacteria, and sulbactam, which helps ampicillin work better by protecting it from certain bacterial defenses.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided to you. It is essential to follow the instructions carefully. This medication can be administered in two ways: as an injection into a muscle or as an infusion into a vein over a period of time. In some cases, it may also be given as an injection directly into a vein.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the best way to store it.
Missing a Dose
If you miss a dose, contact your doctor to find out what steps to take next.
To use this medication correctly, follow your doctor's instructions and read all the information provided to you. It is essential to follow the instructions carefully. This medication can be administered in two ways: as an injection into a muscle or as an infusion into a vein over a period of time. In some cases, it may also be given as an injection directly into a vein.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the best way to store it.
Missing a Dose
If you miss a dose, contact your doctor to find out what steps to take next.
Lifestyle & Tips
- Complete the full course of medication as prescribed, even if you start feeling better, to prevent the infection from returning and to reduce the risk of antibiotic resistance.
- Report any signs of allergic reaction (rash, itching, swelling, difficulty breathing) immediately.
- Report severe or persistent diarrhea, as it could be a sign of a more serious infection (C. difficile).
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
1.5 g (1 g ampicillin/0.5 g sulbactam) to 3 g (2 g ampicillin/1 g sulbactam) IV or IM every 6 hours
Dose Range:
1.5 - 3 mg
Condition-Specific Dosing:
mild_moderate_infections:
1.5 g every 6 hours
severe_infections:
3 g every 6 hours
maximum_daily_dose:
Not to exceed 4 g sulbactam per day (equivalent to 12 g Unasyn)
Pediatric Dosing
Neonatal:
Not established for all indications; consult specific guidelines for age and weight-based dosing (e.g., 75 mg ampicillin/kg/day divided every 12 hours for <7 days old, <2 kg; 150 mg ampicillin/kg/day divided every 8 hours for >7 days old, >2 kg)
Infant:
150 mg (ampicillin) /kg/day (100 mg ampicillin/50 mg sulbactam) divided into doses every 6-8 hours
Child:
150 mg (ampicillin) /kg/day (100 mg ampicillin/50 mg sulbactam) divided into doses every 6-8 hours
Adolescent:
150 mg (ampicillin) /kg/day (100 mg ampicillin/50 mg sulbactam) divided into doses every 6-8 hours, up to adult dose
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl > 30 mL/min)
Moderate:
1.5 g to 3 g every 12 hours (CrCl 15-29 mL/min)
Severe:
1.5 g to 3 g every 24 hours (CrCl 5-14 mL/min)
Dialysis:
Administer after dialysis session on dialysis days. Ampicillin and sulbactam are removed by hemodialysis.
Hepatic Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
No adjustment needed
Pharmacology
Mechanism of Action
Ampicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death. Sulbactam is a beta-lactamase inhibitor that irreversibly binds to and inactivates a wide range of bacterial beta-lactamases, protecting ampicillin from enzymatic hydrolysis and extending its spectrum of activity against beta-lactamase-producing bacteria.
Pharmacokinetics
Absorption:
Bioavailability:
100% (IV administration)
Tmax:
Not applicable (IV administration)
FoodEffect:
Not applicable (IV administration)
Distribution:
Vd:
Ampicillin: 0.28-0.31 L/kg; Sulbactam: 0.24-0.27 L/kg
ProteinBinding:
Ampicillin: 15-28%; Sulbactam: 38%
CnssPenetration:
Limited in uninflamed meninges; increased with meningeal inflammation
Elimination:
HalfLife:
Ampicillin: 1-1.3 hours; Sulbactam: 1-1.3 hours (in patients with normal renal function)
Clearance:
Primarily renal clearance
ExcretionRoute:
Renal (glomerular filtration and tubular secretion)
Unchanged:
Approximately 75-85% of both ampicillin and sulbactam are excreted unchanged in the urine within 8 hours
Pharmacodynamics
OnsetOfAction:
Rapid (IV administration)
PeakEffect:
Within minutes of IV administration
DurationOfAction:
Dependent on half-life and MIC of pathogen; typically dosed every 6-8 hours due to time-dependent killing
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
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
In rare cases, allergic reactions can be fatal.
Diarrhea and Bowel Problems
Diarrhea is a common side effect of antibiotics. However, in rare cases, a severe form of diarrhea called Clostridioides difficile-associated diarrhea (CDAD) may occur. This condition can lead to life-threatening bowel problems. If you experience any of the following symptoms, contact your doctor right away:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Do not treat diarrhea without consulting your doctor first.
Liver Problems
Liver problems have been reported in rare cases, and in some instances, they have been fatal. If you notice any of the following symptoms, contact your doctor immediately:
Dark urine
Tiredness
Decreased appetite
Upset stomach or stomach pain
Light-colored stools
Vomiting
Yellow skin or eyes
Severe Skin Reactions
This medication can cause severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions. These conditions can affect body organs and be life-threatening. Seek medical help right away if you experience:
Red, swollen, blistered, or peeling skin
Red or irritated eyes
Sores in your mouth, throat, nose, eyes, genitals, or any areas of skin
Fever
Chills
Body aches
Shortness of breath
Swollen glands
Other Side Effects
Like all medications, this drug can cause side effects. Many people do not experience any side effects or only have mild ones. However, if you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Diarrhea
* Pain at the injection site (if administered via muscle injection)
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, contact 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, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
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
In rare cases, allergic reactions can be fatal.
Diarrhea and Bowel Problems
Diarrhea is a common side effect of antibiotics. However, in rare cases, a severe form of diarrhea called Clostridioides difficile-associated diarrhea (CDAD) may occur. This condition can lead to life-threatening bowel problems. If you experience any of the following symptoms, contact your doctor right away:
Stomach pain
Cramps
Very loose, watery, or bloody stools
Do not treat diarrhea without consulting your doctor first.
Liver Problems
Liver problems have been reported in rare cases, and in some instances, they have been fatal. If you notice any of the following symptoms, contact your doctor immediately:
Dark urine
Tiredness
Decreased appetite
Upset stomach or stomach pain
Light-colored stools
Vomiting
Yellow skin or eyes
Severe Skin Reactions
This medication can cause severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions. These conditions can affect body organs and be life-threatening. Seek medical help right away if you experience:
Red, swollen, blistered, or peeling skin
Red or irritated eyes
Sores in your mouth, throat, nose, eyes, genitals, or any areas of skin
Fever
Chills
Body aches
Shortness of breath
Swollen glands
Other Side Effects
Like all medications, this drug can cause side effects. Many people do not experience any side effects or only have mild ones. However, if you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Diarrhea
* Pain at the injection site (if administered via muscle injection)
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, contact 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:
- Severe skin rash, blistering, or peeling
- Hives, itching, or swelling (especially of the face, lips, tongue, or throat)
- Difficulty breathing or swallowing
- Wheezing or chest tightness
- Severe or watery diarrhea, especially if it contains blood or mucus
- Persistent nausea or vomiting
- Unusual bleeding or bruising
- Yellowing of the skin or eyes (jaundice)
- Dark urine or pale stools
- Fever or chills that worsen or do not improve
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 and its symptoms.
If you are allergic to penicillin, as this may impact your ability to take this medication safely.
If you have been diagnosed with mononucleosis (mono), as this condition may affect how your body responds to the medication.
If you have previously experienced liver problems or jaundice (turning yellow) while taking this medication, as this may indicate a sensitivity or adverse reaction.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine whether it is safe to take this medication in combination with your other medications and health conditions.
Remember, do not start, stop, or change the dosage of any medication without first consulting your doctor to ensure your safety and the effectiveness of your treatment.
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 and its symptoms.
If you are allergic to penicillin, as this may impact your ability to take this medication safely.
If you have been diagnosed with mononucleosis (mono), as this condition may affect how your body responds to the medication.
If you have previously experienced liver problems or jaundice (turning yellow) while taking this medication, as this may indicate a sensitivity or adverse reaction.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine whether it is safe to take this medication in combination with your other medications and health conditions.
Remember, do not start, stop, or change the dosage of any medication without first consulting your doctor to ensure your safety and the effectiveness of your treatment.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. This drug may interfere with certain laboratory tests, so be sure to notify your healthcare providers and laboratory personnel that you are taking it.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable tests to use, as this medication may affect the results.
Do not take this medication for longer than prescribed, as this may increase the risk of a second infection.
If you are pregnant, planning to become pregnant, or are breastfeeding, inform your doctor. You and your doctor will need to discuss the potential benefits and risks of taking this medication to ensure the best outcome for both you and your baby.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable tests to use, as this medication may affect the results.
Do not take this medication for longer than prescribed, as this may increase the risk of a second infection.
If you are pregnant, planning to become pregnant, or are breastfeeding, inform your doctor. You and your doctor will need to discuss the potential benefits and risks of taking this medication to ensure the best outcome for both you and your baby.
Overdose Information
Overdose Symptoms:
- Neurological effects (e.g., seizures, especially in patients with impaired renal function)
- Gastrointestinal disturbances (e.g., nausea, vomiting, diarrhea)
- Electrolyte imbalances
What to Do:
Seek immediate medical attention. Treatment is supportive and symptomatic. Hemodialysis may be used to remove ampicillin and sulbactam from circulation in cases of severe overdose, especially in patients with renal impairment. Call 1-800-222-1222 (Poison Control).
Drug Interactions
Major Interactions
- Methotrexate (increased methotrexate toxicity due to decreased renal clearance)
- Probenecid (decreased renal tubular secretion of ampicillin and sulbactam, leading to increased and prolonged plasma concentrations)
Moderate Interactions
- Allopurinol (increased incidence of skin rash with ampicillin)
- Oral Contraceptives (may reduce efficacy of oral contraceptives)
- Anticoagulants (e.g., Warfarin - may prolong prothrombin time/INR due to effects on gut flora and vitamin K synthesis)
- Bacteriostatic antibiotics (e.g., tetracyclines, macrolides, chloramphenicol - may antagonize the bactericidal effect of ampicillin)
Monitoring
Baseline Monitoring
Renal function (BUN, serum creatinine, CrCl)
Rationale: Primarily renally eliminated; dose adjustment required in renal impairment.
Timing: Prior to initiation of therapy
Liver function tests (ALT, AST, bilirubin)
Rationale: Although rare, transient elevations have been reported; baseline assessment is prudent, especially in patients with pre-existing hepatic dysfunction.
Timing: Prior to initiation of therapy, if clinically indicated
Routine Monitoring
Clinical response to therapy (resolution of infection symptoms)
Frequency: Daily
Target: Improvement in fever, pain, inflammation
Action Threshold: Lack of improvement or worsening symptoms may indicate treatment failure, resistance, or alternative diagnosis.
Renal function (BUN, serum creatinine)
Frequency: Periodically, especially in prolonged therapy or in patients with pre-existing renal impairment
Target: Within patient's baseline or normal limits
Action Threshold: Significant increase may require dose adjustment or discontinuation.
Complete Blood Count (CBC) with differential
Frequency: Periodically, especially during prolonged therapy (e.g., >2 weeks)
Target: Within normal limits
Action Threshold: Significant changes (e.g., leukopenia, thrombocytopenia, eosinophilia) may indicate drug-induced hematologic effects.
Signs of superinfection (e.g., oral thrush, vaginal candidiasis, C. difficile-associated diarrhea)
Frequency: Daily
Target: Absence of new infections
Action Threshold: Development of new infections requires appropriate management.
Symptom Monitoring
- Skin rash, itching, hives (signs of allergic reaction)
- Difficulty breathing, swelling of face/throat (signs of severe allergic reaction)
- Severe diarrhea, abdominal pain, fever (signs of Clostridioides difficile-associated diarrhea)
- New or worsening fever, chills, sore throat (signs of superinfection)
- Unusual bleeding or bruising (rare hematologic effects)
- Seizures (rare CNS effect, especially with high doses in renal impairment)
Special Patient Groups
Pregnancy
Category B. Studies in animals have shown no evidence of impaired fertility or harm to the fetus. Ampicillin and sulbactam cross the placenta. Use during pregnancy only if clearly needed.
Trimester-Specific Risks:
First Trimester:
No increased risk of congenital anomalies observed in human studies.
Second Trimester:
Generally considered safe; no specific risks identified.
Third Trimester:
Generally considered safe; no specific risks identified. May be used for peripartum prophylaxis if indicated.
Lactation
L1 (Compatible). Both ampicillin and sulbactam are excreted in small amounts into breast milk. Generally considered safe for nursing infants, but monitor for potential effects such as diarrhea, candidiasis (thrush), or allergic reactions.
Infant Risk:
Low risk. Potential for mild gastrointestinal upset (diarrhea) or sensitization (allergic reaction) in the infant, but generally well-tolerated.
Pediatric Use
Dosing must be carefully calculated based on age, weight, and renal function. Neonates and young infants have immature renal function, requiring specific dosing adjustments. Safety and efficacy in neonates have not been fully established for all indications.
Geriatric Use
No specific dose adjustment is required based solely on age, but elderly patients are more likely to have decreased renal function. Renal function should be assessed, and dosage adjusted accordingly to prevent accumulation and potential toxicity.
Clinical Information
Clinical Pearls
- Unasyn is a broad-spectrum antibiotic effective against many Gram-positive, Gram-negative, and anaerobic bacteria, including beta-lactamase producing strains.
- Commonly used for skin and soft tissue infections, intra-abdominal infections, gynecological infections, and community-acquired pneumonia.
- Not effective against MRSA, Pseudomonas aeruginosa, or atypical pathogens.
- Reconstituted solutions should be used promptly; stability varies with diluent and concentration.
- Monitor for C. difficile-associated diarrhea, which can occur even weeks after discontinuation of antibiotics.
- Consider therapeutic drug monitoring for ampicillin/sulbactam in critically ill patients or those with fluctuating renal function, although not routinely performed.
Alternative Therapies
- Carbapenems (e.g., Meropenem, Imipenem/cilastatin, Ertapenem) for broader spectrum or resistant infections
- Cephalosporins (e.g., Ceftriaxone, Cefoxitin, Cefotetan) for specific indications
- Fluoroquinolones (e.g., Moxifloxacin, Levofloxacin) for certain infections
- Metronidazole (for anaerobic coverage, often in combination with other agents)
Cost & Coverage
Average Cost:
Varies widely by pharmacy, dosage, and insurance plan per vial
Generic Available:
Yes
Insurance Coverage:
Typically covered by most insurance plans, often as a Tier 2 or Tier 3 medication, or as a preferred generic.
General Drug Facts
If your symptoms or health problems persist or worsen, it is essential to contact your doctor promptly. 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 the 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 pour them down the 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 call your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication taken, the amount, and the time it was taken to ensure timely and effective treatment.