unasyn
Pharmaranks rates Unasyn 2.8/5 for recall safety — an independent score from its FDA recall history and its manufacturer's record. Unasyn is a combination medicine containing Ampicillin Sodium and Sulbactam Sodium.
Ampicillin Sodium and Sulbactam Sodium · by Pfizer
Available as a generic: Ampicillin and Sulbactam
Based on 1 source · Recall-safety score from FDA recall history — this product's own recalls and its manufacturer's record. Not an efficacy or quality rating. methodology →
Key facts
- Active ingredient
- Ampicillin Sodium and Sulbactam Sodium
- Form
- Injectable
- Strength
- Ampicillin Sodium EQ 10GM BASE/VIAL; Sulbactam Sodium EQ 5GM BASE/VIAL · Ampicillin Sodium EQ 1GM BASE/VIAL; Sulbactam Sodium EQ 500MG BASE/VIAL · Ampicillin Sodium EQ 2GM BASE/VIAL; Sulbactam Sodium EQ 1GM BASE/VIAL · Ampicillin Sodium EQ 500MG BASE/VIAL; Sulbactam Sodium EQ 250MG BASE/VIAL
- Type
- Prescription (Rx)
- Brand or generic
- Brand-name
- Manufacturer
- Pfizer
- What the pharmacy pays
- ~$13.74 for 30 — not your price
- FDA application
- NDA050608
What is Unasyn?
From the FDA label:UNASYN (ampicillin and sulbactam) for injection, USP is a sterile antibacterial fixed-combination drug product consisting of the semisynthetic antibacterial ampicillin sodium and the beta-lactamase inhibitor sulbactam sodium for intravenous and intramuscular administration. Ampicillin sodium is derived from the penicillin nucleus, 6-aminopenicillanic acid. Chemically, it is monosodium (2S, 5R, 6R)-6-[(R)-2-amino-2-phenylacetamido]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate and has a molecular weight of 371.39. Its chemical formula is C 16 H 18 N 3 NaO 4 S. The structural formula is: Sulbactam sodium is a derivative of the basic penicillin nucleus. Chemically, sulbactam sodium is sodium penicillinate sulfone; sodium (2S, 5R)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo [3.2.0]heptane-2-carboxylate 4,4-dioxide. Its chemical formula is C 8 H 10 NNaO 5 S with a molecular weight of 255.22. The structural formula is: UNASYN is available as a white to off-white dry powder for reconstitution. UNASYN dry powder is freely soluble in aqueous diluents to yield pale yellow to yellow solutions. The pH of the solutions is between 8.0 and 10.0. Dilute solutions (up to 30 mg ampicillin and 15 mg sulbactam per mL) are essentially colorless to pale yellow. The pH of dilute solutions remains the same. UNASYN pharmacy bulk package is a vial containing a sterile preparation for…
How to use
The pharmacy bulk package is for preparation of solutions for IV infusion only. UNASYN should be administered diluted with 50 mL to 100 mL of a compatible diluent as an intravenous infusion over 15–30 minutes. The recommended adult dosage of UNASYN is 1.5 g (ampicillin 1 g and sulbactam 0.5 g) to 3 g (ampicillin 2 g and sulbactam 1 g) every six hours. This 1.5 g to 3 g range represents the total of ampicillin content plus the sulbactam content of UNASYN, and corresponds to a range of 1 g ampicillin and 0.5 g sulbactam to 2 g ampicillin and 1 g sulbactam. The total dose of sulbactam should not exceed 4 g per day. Pediatric Patients 1 Year of Age or Older The recommended daily dose of UNASYN in pediatric patients is 300 mg per kg of body weight administered via intravenous infusion in equally divided doses every 6 hours. This 300 mg/kg/day dosage represents the total ampicillin content plus the sulbactam content of UNASYN, and corresponds to 200 mg ampicillin and 100 mg sulbactam per kg per day. The safety and efficacy of UNASYN administered via intramuscular injection in pediatric patients have not been established. Pediatric patients weighing 40 kg or more should be dosed according to adult recommendations, and the total dose of sulbactam should not exceed 4 g per day. The course of intravenous therapy should not routinely exceed 14 days. In clinical trials, most pediatric…
Side effects
Adult Patients UNASYN is generally well tolerated. The following adverse reactions have been reported in clinical trials. Local Adverse Reactions Pain at IM injection site – 16% Pain at IV injection site – 3% Thrombophlebitis – 3% Phlebitis – 1.2% Systemic Adverse Reactions The most frequently reported adverse reactions were diarrhea in 3% of the patients and rash in less than 2% of the patients. Additional systemic reactions reported in less than 1% of the patients were: itching, nausea, vomiting, candidiasis, fatigue, malaise, headache, chest pain, flatulence, abdominal distension, glossitis, urine retention, dysuria, edema, facial swelling, erythema, chills, tightness in throat, substernal pain, epistaxis and mucosal bleeding. Pediatric Patients Available safety data for pediatric patients treated with UNASYN demonstrate a similar adverse events profile to those observed in adult patients. Additionally, atypical lymphocytosis has been observed in one pediatric patient receiving UNASYN. Adverse Laboratory Changes Adverse laboratory changes without regard to drug relationship that were reported during clinical trials were: Hepatic: Increased AST (SGOT), ALT (SGPT), alkaline phosphatase, and LDH. Hematologic: Decreased hemoglobin, hematocrit, RBC, WBC, neutrophils, lymphocytes, platelets and increased lymphocytes, monocytes, basophils, eosinophils, and platelets. Blood…
Warnings
Important safety information
Hypersensitivity Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients on penicillin therapy. These reactions are more apt to occur in individuals with a history of penicillin hypersensitivity and/or hypersensitivity reactions to multiple allergens. There have been reports of individuals with a history of penicillin hypersensitivity who have experienced severe reactions when treated with cephalosporins. Before therapy with a penicillin, careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, and other allergens. If an allergic reaction occurs, UNASYN should be discontinued and the appropriate therapy instituted. Hepatotoxicity Hepatic dysfunction, including hepatitis and cholestatic jaundice has been associated with the use of UNASYN. Hepatic toxicity is usually reversible; however, deaths have been reported. Hepatic function should be monitored at regular intervals in patients with hepatic impairment. Severe Cutaneous Adverse Reactions UNASYN may cause severe skin reactions, such as toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), drug reaction with eosinophilia and systemic symptoms (DRESS), dermatitis exfoliative, erythema multiforme, and Acute generalized exanthematous pustulosis (AGEP). If patients develop a skin rash they should be monitored closely and UNASYN discontinued if lesions progress (see CONTRAINDICATIONS and ADVERSE REACTIONS sections). Clostridioides difficile -Associated Diarrhea Clostridioides difficile -associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including UNASYN, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibacterial drug use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibacterial drug use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile , and surgical evaluation should be instituted as clinically indicated.
Who should not take Unasyn
The use of UNASYN is contraindicated in individuals with a history of serious hypersensitivity reactions (e.g., anaphylaxis or Stevens-Johnson syndrome) to ampicillin, sulbactam or to other beta-lactam antibacterial drugs (e.g., penicillins and cephalosporins). UNASYN is contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with UNASYN.
Overdose — what happens if you take too much
Neurological adverse reactions, including convulsions, may occur with the attainment of high CSF levels of beta-lactams. Ampicillin may be removed from circulation by hemodialysis. The molecular weight, degree of protein binding and pharmacokinetics profile of sulbactam suggest that this compound may also be removed by hemodialysis.
U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.
Interactions
Probenecid decreases the renal tubular secretion of ampicillin and sulbactam. Concurrent use of probenecid with UNASYN may result in increased and prolonged blood levels of ampicillin and sulbactam. The concurrent administration of allopurinol and ampicillin increases substantially the incidence of rashes in patients receiving both drugs as compared to patients receiving ampicillin alone. It is not known whether this potentiation of ampicillin rashes is due to allopurinol or the hyperuricemia present in these patients. There are no data with UNASYN and allopurinol administered concurrently. UNASYN and aminoglycosides should not be reconstituted together due to the in vitro inactivation of aminoglycosides by the ampicillin component of UNASYN.
Dosage forms
Injectable
The forms currently marketed in the U.S., per the FDA National Drug Code Directory.
Ways to save
Ask for the generic
Same active ingredient, far cheaper. Is there a generic? →
Request a 90-day supply
Bulk fills usually lower the per-dose price vs monthly refills.
Use copay cards
Manufacturer copay cards & patient-assistance programs — especially for brand drugs.
Compare alternatives
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Frequently asked questions
- How is Unasyn rated?
- pharmaranks gives Unasyn a composite score of 2.8 out of 5, currently based on 1 weighted source (FDA regulatory recall-safety data weighted highest). See our methodology at /how-we-rate.
- How much does Unasyn cost?
- Nobody can tell you what you will pay — your price is set by your insurer's formulary, your deductible and the pharmacy's markup, and none of those are published. What IS published is what the pharmacy paid to acquire it: about $13.74 for 30, per the CMS NADAC survey. Treat that as the floor, not the quote — ask the pharmacist for the cash price as well as your copay, because for cheap generics the cash price often wins.
- Is there a coupon or discount for Unasyn?
- pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Unasyn. To pay less, ask your prescriber or pharmacist whether a generic equivalent exists, check the manufacturer's copay/savings card and patient-assistance program, and compare a pharmacy discount card against your insurance copay. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
- Who makes Unasyn?
- Unasyn is marketed by Pfizer. You can see Pfizer's full profile, rating, and other products on pharmaranks.
- Is Unasyn a brand-name or generic drug?
- Unasyn is a brand-name product with the active ingredient Ampicillin Sodium and Sulbactam Sodium. Lower-cost generic equivalents containing Ampicillin Sodium and Sulbactam Sodium are available — ask your pharmacist.
- Is Unasyn available over the counter?
- No. Unasyn is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
- What forms does Unasyn come in?
- Unasyn is currently marketed as injectable, per the FDA's National Drug Code Directory.
- Is Unasyn FDA-registered?
- Unasyn is on record with the U.S. FDA under application number NDA050608. You can verify this on its official FDA label.
- Has Unasyn been recalled by the FDA?
- Yes. Unasyn has 1 recorded FDA recall event in the openFDA enforcement database. A recall removes specific lots from the market — usually for manufacturing, contamination, potency, or labeling issues — and does not mean the drug is unsafe to take; your specific lot was almost certainly never affected. This recall history is factored into its safety score above. Always check the FDA recall database or your pharmacist for current alerts.
- Is Unasyn safe?
- There's no single safe-or-not verdict. pharmaranks gives Unasyn a recall-safety score of 56/100, based on its FDA recall history (1 recorded recall event) — not an efficacy or side-effect rating. Review its FDA-label side effects and warnings before use, and always consult a licensed professional.
- What are the side effects of Unasyn?
- Unasyn's side effects are taken directly from its FDA label. From the label: Adult Patients UNASYN is generally well tolerated. The following adverse reactions have been reported in clinical trials. Local Adverse Reactions Pain at IM injection site – 16% Pain at IV injection site – 3% Thrombophlebitis – 3% Phlebitis – 1.2% Systemic Adverse Reactions The most frequently repor… Both common and serious reactions are documented in full on this page. This is general reference from the FDA, not medical advice — always consult a professional.
Clinical content sourced from the FDA label via openFDA (U.S. FDA). View the FDA label on DailyMed → Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.
What people report to the FDA about AMPICILLIN SODIUM AND SULBACTAM SODIUM
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 24 reports naming AMPICILLIN SODIUM AND SULBACTAM SODIUM — the active ingredient in Unasyn, and the FDA flagged 100% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- pneumonia4 reports
- brain oedema3 reports
- hepatitis fulminant2 reports
- infection2 reports
- liver disorder2 reports
- platelet count decreased2 reports
- sepsis2 reports
- thrombocytopenia2 reports
Read these as a signal, not a rate. A report does not mean AMPICILLIN SODIUM AND SULBACTAM SODIUM caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label.
Source: openFDA drug/event (FAERS), retrieved September 25, 2026.
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unasyn
56/100