Unasyn 1.5gm Inj 1 Vial
It is used to treat bacterial infections.
Drug Class
Antibiotic, Beta-lactamase inhibitor combination
Pharmacologic Class
Penicillin antibiotic; Beta-lactamase inhibitor
Pregnancy Category
Category B
FDA Approved
Feb 1986
DEA Schedule
Not Controlled
Overview
What is this medicine?
Unasyn is an antibiotic medication given by injection to treat serious bacterial infections. It contains two active ingredients: ampicillin, which kills bacteria by stopping them from building their cell walls, and sulbactam, which protects ampicillin from being destroyed by certain bacteria, making the antibiotic more effective.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Administer the medication as directed, which may involve receiving it as an injection into a muscle or as an infusion into a vein over a period of time. In some cases, it may 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 proper storage procedure.
Missing a Dose
If you miss a dose, contact your doctor to receive guidance on what to do next.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Administer the medication as directed, which may involve receiving it as an injection into a muscle or as an infusion into a vein over a period of time. In some cases, it may 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 proper storage procedure.
Missing a Dose
If you miss a dose, contact your doctor to receive guidance on what to do next.
Lifestyle & Tips
- It is crucial to complete the entire course of treatment as prescribed, even if symptoms improve, to prevent the infection from returning and to reduce the risk of antibiotic resistance.
- Report any new or worsening symptoms, especially severe diarrhea, rash, or difficulty breathing, to your healthcare provider immediately.
- Maintain good hydration, especially if experiencing diarrhea.
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:
severeInfections:
3 g every 6 hours (maximum 4 g sulbactam per day)
mildToModerateInfections:
1.5 g every 6 hours
Pediatric Dosing
Neonatal:
Not established for routine use; off-label use may be considered in specific severe infections (e.g., 75 mg/kg/dose IV every 8-12 hours for infants <7 days old or <2 kg, or every 6-8 hours for infants >7 days old or >2 kg)
Infant:
300 mg/kg/day (200 mg/kg/day ampicillin and 100 mg/kg/day sulbactam) IV or IM in divided doses every 6 hours
Child:
300 mg/kg/day (200 mg/kg/day ampicillin and 100 mg/kg/day sulbactam) IV or IM in divided doses every 6 hours (maximum 4 g sulbactam per day)
Adolescent:
Adult dosing (1.5 g to 3 g IV or IM every 6 hours)
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 <15 mL/min)
Dialysis:
Administer after dialysis on dialysis days; 1.5 g to 3 g every 24 hours on non-dialysis days
Hepatic Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
No adjustment needed
Pharmacology
Mechanism of Action
Ampicillin 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-lactamase enzymes, thereby protecting ampicillin from hydrolysis and extending its spectrum of activity against beta-lactamase-producing bacteria.
Pharmacokinetics
Absorption:
Bioavailability:
100% (IV administration)
Tmax:
End of infusion (IV)
FoodEffect:
Not applicable for IV/IM formulation
Distribution:
Vd:
Ampicillin: Approximately 0.28 L/kg; Sulbactam: Approximately 0.24 L/kg
ProteinBinding:
Ampicillin: Approximately 28%; Sulbactam: Approximately 38%
CnssPenetration:
Limited in the absence of meningeal inflammation; increased penetration with inflamed meninges
Elimination:
HalfLife:
Ampicillin: Approximately 1 hour; Sulbactam: Approximately 1 hour (in patients with normal renal function)
Clearance:
Ampicillin: Approximately 200-300 mL/min; Sulbactam: Approximately 150-250 mL/min
ExcretionRoute:
Primarily renal (glomerular filtration and tubular secretion)
Unchanged:
Approximately 75-85% of both ampicillin and sulbactam are excreted unchanged in urine within 8 hours
Pharmacodynamics
OnsetOfAction:
Rapid (within minutes of IV administration)
PeakEffect:
Achieved at the end of IV infusion
DurationOfAction:
Dependent on MIC of pathogen and dosing frequency; 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 immediate medical attention:
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 C. diff-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
In rare cases, this medication can cause liver problems, which can be 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 minor ones. If you are bothered by any of the following side effects or if they do not go away, contact your doctor:
Diarrhea
* Pain at the injection site (if given intramuscularly)
Reporting Side Effects
This is not an exhaustive list of possible 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 immediate medical attention:
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 C. diff-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
In rare cases, this medication can cause liver problems, which can be 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 minor ones. If you are bothered by any of the following side effects or if they do not go away, contact your doctor:
Diarrhea
* Pain at the injection site (if given intramuscularly)
Reporting Side Effects
This is not an exhaustive list of possible 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 or watery diarrhea (especially if persistent or bloody, which could indicate C. difficile infection)
- New or worsening skin rash, hives, or itching
- Swelling of the face, lips, tongue, or throat
- Difficulty breathing or wheezing
- Unusual bleeding or bruising
- Signs of a new infection (e.g., fever, sore throat, white patches in mouth, vaginal itching or discharge)
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 (turned 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 if 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 plan.
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 (turned 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 if 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 plan.
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 all 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 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 you and your baby.
Overdose Information
Overdose Symptoms:
- Neurological effects, including seizures (especially in patients with impaired renal function)
- Gastrointestinal upset (nausea, vomiting, diarrhea)
- Electrolyte imbalances
What to Do:
In case of suspected overdose, seek immediate medical attention or call a poison control center (e.g., 1-800-222-1222 in the US). Treatment is symptomatic and supportive. Hemodialysis can remove ampicillin and sulbactam from the circulation.
Drug Interactions
Major Interactions
- Allopurinol (increased incidence of skin rash with ampicillin)
- Oral Contraceptives (may reduce efficacy of oral contraceptives; advise backup birth control)
- Probenecid (decreases renal tubular secretion of ampicillin and sulbactam, resulting in increased and prolonged plasma concentrations)
- Tetracyclines (may antagonize the bactericidal effect of penicillins)
Moderate Interactions
- Methotrexate (penicillins may decrease renal clearance of methotrexate, increasing toxicity)
- Anticoagulants (may enhance the effect of anticoagulants by affecting platelet aggregation and gut flora)
Monitoring
Baseline Monitoring
Renal function (Serum Creatinine, BUN)
Rationale: To establish baseline kidney function and guide dosing adjustments, especially in elderly or renally impaired patients.
Timing: Prior to initiation of therapy
Liver function (AST, ALT)
Rationale: To establish baseline liver function, though hepatic impairment rarely requires dose adjustment.
Timing: Prior to initiation of therapy
Complete Blood Count (CBC) with differential
Rationale: To establish baseline hematologic status, especially for prolonged therapy.
Timing: Prior to initiation of therapy
Routine Monitoring
Renal function (Serum Creatinine, BUN)
Frequency: Periodically, especially in patients with pre-existing renal impairment or prolonged therapy
Target: Maintain within patient's baseline or acceptable limits
Action Threshold: Significant increase in creatinine or BUN may necessitate dose adjustment
Signs and symptoms of superinfection (e.g., oral candidiasis, vaginal candidiasis, C. difficile-associated diarrhea)
Frequency: Daily during therapy and for several weeks post-therapy
Target: Absence of new infections
Action Threshold: Development of new infections requires evaluation and appropriate treatment
Complete Blood Count (CBC) with differential
Frequency: Weekly for prolonged therapy (>2 weeks)
Target: Maintain within normal limits
Action Threshold: Significant changes (e.g., leukopenia, thrombocytopenia) may warrant discontinuation
Symptom Monitoring
- Allergic reactions (rash, pruritus, urticaria, dyspnea, angioedema)
- Gastrointestinal disturbances (nausea, vomiting, diarrhea, abdominal pain)
- Signs of Clostridioides difficile-associated diarrhea (CDAD) (severe, persistent diarrhea, abdominal cramps, fever)
- Injection site reactions (pain, tenderness, phlebitis)
- Neurological symptoms (seizures, especially with high doses in renal impairment)
- Signs of superinfection (e.g., new fever, worsening symptoms, white patches in mouth, vaginal itching/discharge)
Special Patient Groups
Pregnancy
Ampicillin/sulbactam is classified as Pregnancy Category B. Studies in animals have not shown evidence of harm to the fetus, but there are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if clearly needed and the potential benefits outweigh the potential risks.
Trimester-Specific Risks:
First Trimester:
No specific increased risk identified, but generally, drug exposure should be minimized during organogenesis.
Second Trimester:
Considered relatively safe if clinically indicated.
Third Trimester:
Considered relatively safe if clinically indicated; no known adverse effects on labor or delivery.
Lactation
Both ampicillin and sulbactam are excreted into breast milk in low concentrations. The American Academy of Pediatrics considers ampicillin compatible with breastfeeding. Sulbactam is also generally considered safe. Monitor breastfed infants for potential adverse effects such as diarrhea, candidiasis (thrush, diaper rash), or allergic reactions (e.g., rash).
Infant Risk:
Low risk; potential for mild gastrointestinal upset or sensitization.
Pediatric Use
Dosing is weight-based and adjusted for age. Neonatal use is off-label and requires careful consideration due to immature renal function. Children are at risk for C. difficile-associated diarrhea. Close monitoring for adverse effects is essential.
Geriatric Use
Dose adjustment is necessary for elderly patients with renal impairment, as renal function often declines with age. Elderly patients may be more susceptible to adverse effects, including C. difficile infection and neurological effects (e.g., seizures) if accumulation occurs due to impaired renal clearance.
Clinical Information
Clinical Pearls
- Unasyn is a broad-spectrum antibiotic effective against many Gram-positive, Gram-negative, and anaerobic bacteria, including those that produce beta-lactamase enzymes.
- It is commonly used for polymicrobial infections, such as intra-abdominal infections, gynecological infections, and skin and skin structure infections.
- Unasyn is NOT effective against MRSA (Methicillin-Resistant Staphylococcus aureus) or Pseudomonas aeruginosa.
- Administer IV infusions slowly over 15-30 minutes to minimize the risk of infusion-related reactions.
- Due to its renal excretion, significant dose adjustments are required in patients with renal impairment.
- Always confirm patient allergies to penicillins or cephalosporins before administration due to potential cross-reactivity.
Alternative Therapies
- Carbapenems (e.g., Imipenem/cilastatin, Meropenem, Ertapenem) for broader spectrum or more severe infections
- Certain cephalosporins (e.g., Cefoxitin, Cefotetan) for anaerobic coverage
- Metronidazole (for anaerobic infections, often in combination with other agents)
- Fluoroquinolones (e.g., Moxifloxacin) for some intra-abdominal or skin infections
- Tigecycline (for complicated skin and skin structure infections, intra-abdominal infections)
Cost & Coverage
Average Cost:
Varies widely by pharmacy, formulation, and quantity (e.g., $10-$50 per 1.5g vial) per 1.5g vial
Generic Available:
Yes
Insurance Coverage:
Generally covered by most insurance plans, often as a Tier 1 or Tier 2 medication due to generic availability.
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 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 contact your local poison control center or seek medical attention. Be prepared to provide information about the medication taken, the quantity, and the time of ingestion.