Recommended Topic Related To:


"On April 1, 2013, the World Health Organization (WHO) first reported 3 human infections with a new influenza A (H7N9) virus in China. Since then, additional cases have been reported. Most reported cases have severe respiratory illness and, in som"...


Zosyn Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 5/15/2015

Zosyn (piperacillin and tazobactam for injection) is a combination of two antibiotics used to treat many different infections caused by bacteria, such as urinary tract infections, bone and joint infections, severe vaginal infections, stomach infections, skin infections, and pneumonia. Zosyn is available in generic form. Common side effects of Zosyn include swelling/redness/pain/soreness at the injection site, dizziness, agitation, trouble sleeping (insomnia), nausea, vomiting, stomach pain or upset, diarrhea, constipation, headache, runny nose, anxiety, skin rash or itching, or vaginal discharge or itching.

The usual total daily dose of Zosyn for adults is 3.375 g every six hours totaling 13.5 g (12.0 g piperacillin/1.5 g tazobactam). Zosyn may interact with probenecid, antibiotics, blood thinners, or any other medication used to prevent blood clots. Tell your doctor all medications you use. During pregnancy, Zosyn should be used only when prescribed. This medication may pass into breast milk. Consult your doctor before breast-feeding.

Our Zosyn (piperacillin and tazobactam for injection, USP) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

Zosyn in Detail - Patient Information: Side Effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

  • diarrhea that is watery or bloody;
  • pale or yellowed skin, dark colored urine, fever, confusion or weakness;
  • feeling light-headed or short of breath, rapid heart rate, trouble concentrating;
  • easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;
  • dry mouth, increased thirst, confusion, increased urination, muscle pain or weakness, fast heart rate, feeling light-headed, fainting;
  • fever, chills, body aches, flu symptoms;
  • white patches or sores inside your mouth or on your lips; or
  • seizure (convulsions).

Less serious side effects may include:

  • nausea, vomiting, stomach pain or upset;
  • constipation, mild diarrhea;
  • headache, dizziness, agitation;
  • runny nose;
  • anxiety, sleep problems (insomnia);
  • skin rash or itching;
  • pain, swelling, or other irritation where the injection was given; or
  • vaginal itching or discharge.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Zosyn (Piperacillin and Tazobactam Injection)

What is Patient Information Overview?

A concise overview of the drug for the patient or caregiver from First DataBank.

Zosyn Overview - Patient Information: Side Effects

SIDE EFFECTS: Swelling, redness, pain, and soreness at the injection site may occur. Dizziness, trouble sleeping, nausea, vomiting, diarrhea, and headache may also occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: muscle cramps/spasms, swelling of the arms/legs/hands/feet, easy bruising/bleeding, chest pain, confusion, new signs of infection (such as fever, persistent sore throat), severe abdominal/stomach pain, slow/fast/irregular heartbeat, persistent nausea/vomiting, seizures, extreme tiredness, dark/cloudy urine, change in the amount of urine, yellowing eyes/skin.

Serious skin reactions can occur. Tell your doctor right away if you develop rash, peeling, sores or blisters on the skin.

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.

Do not use anti-diarrhea products or narcotic pain medications if you have any of these symptoms because these products may make them worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the entire patient information overview for Zosyn (Piperacillin and Tazobactam Injection)

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Zosyn FDA Prescribing Information: Side Effects
(Adverse Reactions)


Adverse Events From Clinical Trials

During the initial clinical investigations, 2621 patients worldwide were treated with ZOSYN (piperacillin and tazobactam for injection, USP) in phase 3 trials. In the key North American clinical trials (n=830 patients), 90% of the adverse events reported were mild to moderate in severity and transient in nature. However, in 3.2% of the patients treated worldwide, ZOSYN was discontinued because of adverse events primarily involving the skin (1.3%), including rash and pruritus; the gastrointestinal system (0.9%), including diarrhea, nausea, and vomiting; and allergic reactions (0.5%).

Adverse local reactions that were reported, irrespective of relationship to therapy with ZOSYN, were phlebitis (1.3%), injection site reaction (0.5%), pain (0.2%), inflammation (0.2%), thrombophlebitis (0.2%), and edema (0.1%).

Based on patients from the North American trials (n=1063), the events with the highest incidence in patients, irrespective of relationship to ZOSYN therapy, were diarrhea (11.3%); headache (7.7%); constipation (7.7%); nausea (6.9%); insomnia (6.6%); rash (4.2%), including maculopapular, bullous, urticarial, and eczematoid; vomiting (3.3%); dyspepsia (3.3%); pruritus (3.1%); stool changes (2.4%); fever (2.4%); agitation (2.1%); pain (1.7%); moniliasis (1.6%); hypertension (1.6%); dizziness (1.4%); abdominal pain (1.3%); chest pain (1.3%); edema (1.2%); anxiety (1.2%); rhinitis (1.2%); and dyspnea (1.1%).

Additional adverse systemic clinical events reported in 1.0% or less of the patients in the initial North American trials are listed below within each body system.

AutonomicNervous System-hypotension, ileus, syncope

Body as a whole-rigors, back pain, malaise

Cardiovascular-tachycardia, including supraventricular and ventricular; bradycardia; arrhythmia, including atrial fibrillation, ventricular fibrillation, cardiac arrest, cardiac failure, circulatory failure, myocardial infarction

Central Nervous System-tremor, convulsions, vertigo

Gastrointestinal-melena, flatulence, hemorrhage, gastritis, hiccough, ulcerative stomatitis

Pseudomembranous colitis was reported in one patient during the clinical trials. The onset of pseudomembranous colitis symptoms may occur during or after antibacterial treatment. (See WARNINGS.)

Hearing and Vestibular System-tinnitus


Metabolic and Nutritional-symptomatic hypoglycemia, thirst

Musculoskeletal-myalgia, arthralgia

Platelets, Bleeding, Clotting-mesenteric embolism, purpura, epistaxis, pulmonary embolism (see PRECAUTIONS, General).

Psychiatric-confusion, hallucination, depression

Reproductive, Female-leukorrhea, vaginitis

Respiratory-pharyngitis, pulmonary edema, bronchospasm, coughing

Skin and Appendages-genital pruritus, diaphoresis

Special senses-taste perversion

Urinary-retention, dysuria, oliguria, hematuria, incontinence


Vascular (extracardiac)-flushing

Nosocomial Pneumonia Trials

In a completed study of nosocomial lower respiratory tract infections, 222 patients were treated with ZOSYN in a dosing regimen of 4.5 g every 6 hours in combination with an aminoglycoside and 215 patients were treated with imipenem/cilastatin (500 mg/500 mg q6h) in combination with an aminoglycoside. In this trial, treatment-emergent adverse events were reported by 402 patients, 204 (91.9%) in the piperacillin/tazobactam group and 198 (92.1%) in the imipenem/cilastatin group. Twenty-five (11.0%) patients in the piperacillin/tazobactam group and 14 (6.5%) in the imipenem/cilastatin group (p > 0.05) discontinued treatment due to an adverse event.

In this study of ZOSYN in combination with an aminoglycoside, adverse events that occurred in more than 1% of patients and were considered by the investigator to be drug-related were: diarrhea (17.6%), fever (2.7%), vomiting (2.7%), urinary tract infection (2.7%), rash (2.3%), abdominal pain (1.8%), generalized edema (1.8%), moniliasis (1.8%), nausea (1.8%), oral moniliasis (1.8%), BUN increased (1.8%), creatinine increased (1.8%), peripheral edema (1.8%), abdomen enlarged (1.4%), headache (1.4%), constipation (1.4%), liver function tests abnormal (1.4%), thrombocythemia (1.4%), excoriations (1.4%), and sweating (1.4%).

Drug-related adverse events reported in 1% or less of patients in the nosocomial pneumonia study of ZOSYN with an aminoglycoside were: acidosis, acute kidney failure, agitation, alkaline phosphatase increased, anemia, asthenia, atrial fibrillation, chest pain, CNS depression, colitis, confusion, convulsion, cough increased, thrombocytopenia, dehydration, depression, diplopia, drug level decreased, dry mouth, dyspepsia, dysphagia, dyspnea, dysuria, eosinophilia, fungal dermatitis, gastritis, glossitis, grand mal convulsion, hematuria, hyperglycemia, hypernatremia, hypertension, hypertonia, hyperventilation, hypochromic anemia, hypoglycemia, hypokalemia, hyponatremia, hypophosphatemia, hypoxia, ileus, injection site edema, injection site pain, injection site reaction, kidney function abnormal, leukocytosis, leukopenia, local reaction to procedure, melena, pain, prothrombin decreased, pruritus, respiratory disorder, SGOT increased, SGPT increased, sinus bradycardia, somnolence, stomatitis, stupor, tremor, tachycardia, ventricular extrasystoles, and ventricular tachycardia.

In a previous nosocomial pneumonia study conducted with a dosing regimen of 3.375 g given every 4 hours with an aminoglycoside, the following adverse events, irrespective of drug relationship, were observed: diarrhea (20%); constipation (8.4%); agitation (7.1%); nausea (5.8%); headache (4.5%); insomnia (4.5%); oral thrush (3.9%); erythematous rash (3.9%); anxiety (3.2%); fever (3.2%); pain (3.2%); pruritus (3.2%); hiccough (2.6%); vomiting (2.6%); dyspepsia (1.9%); edema (1.9%); fluid overload (1.9%); stool changes (1.9%); anorexia (1.3%); cardiac arrest (1.3%); confusion (1.3%); diaphoresis (1.3%); duodenal ulcer (1.3%); flatulence (1.3%); hypertension (1.3%); hypotension (1.3%); inflammation at injection site (1.3%); pleural effusion (1.3%); pneumothorax (1.3%); rash, not otherwise specified (1.3%); supraventricular tachycardia (1.3%); thrombophlebitis (1.3%); and urinary incontinence (1.3%).

Adverse events irrespective of drug relationship observed in 1% or less of patients in the above study with ZOSYN and an aminoglycoside included: aggressive reaction (combative), angina, asthenia, atelectasis, balanoposthitis, cerebrovascular accident, chest pain, conjunctivitis, deafness, dyspnea, earache, ecchymosis, fecal incontinence, gastric ulcer, gout, hemoptysis, hypoxia, pancreatitis, perineal irritation/pain, urinary tract infection with trichomonas, vitamin B12 deficiency anemia, xerosis, and yeast in urine.


Studies of ZOSYN in pediatric patients suggest a similar safety profile to that seen in adults. In a prospective, randomized, comparative, open-label clinical trial of pediatric patients with severe intra-abdominal infections (including appendicitis and/or peritonitis), 273 patients were treated with ZOSYN (112.5 mg/kg every 8 hours) and 269 patients were treated with cefotaxime (50 mg/kg) plus metronidazole (7.5 mg/kg) every 8 hours. In this trial, treatment-emergent adverse events were reported by 146 patients, 73 (26.7%) in the ZOSYN group and 73 (27.1%) in the cefotaxime/metronidazole group. Six patients (2.2%) in the ZOSYN group and 5 patients (1.9%) in the cefotaxime/metronidazole group discontinued due to an adverse event.

In this study, adverse events that were reported in more than 1% of patients, irrespective of relationship to therapy with ZOSYN, were: diarrhea (7.0%), fever (4.8%), vomiting (3.7%), local reaction (3.3%), abscess (2.2%), sepsis (2.2%), abdominal pain (1.8%), infection (1.8%), bloody diarrhea (1.1%), pharyngitis (1.5%), constipation (1.1%), and SGOT increase (1.1%).

Adverse events reported in 1% or less of pediatric patients receiving ZOSYN are consistent with adverse events reported in adults.

Additional controlled studies in pediatric patients showed a similar safety profile as that described above.

Post-Marketing Experience

Additional adverse events reported from worldwide marketing experience with ZOSYN, occurring under circumstances where causal relationship to ZOSYN is uncertain:

Gastrointestinal-hepatitis, cholestatic jaundice

Hematologic-hemolytic anemia, anemia, thrombocytosis, agranulocytosis, pancytopenia

Immune-hypersensitivity reactions, anaphylactic/anaphylactoid reactions (including shock)

Infections-candidal superinfections

Renal-interstitial nephritis, renal failure

Skin and Appendages-erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis

Post-marketing experience with ZOSYN in pediatric patients suggests a similar safety profile to that seen in adults.

Adverse Laboratory Events (Seen During Clinical Trials)

Of the studies reported, including that of nosocomial lower respiratory tract infections in which a higher dose of ZOSYN (piperacillin and tazobactam for injection, USP) was used in combination with an aminoglycoside, changes in laboratory parameters, without regard to drug relationship, include:

Hematologic-decreases in hemoglobin and hematocrit, thrombocytopenia, increases in platelet count, eosinophilia, leukopenia, neutropenia. The leukopenia/neutropenia associated with ZOSYN administration appears to be reversible and most frequently associated with prolonged administration, i.e., ≥ 21 days of therapy. These patients were withdrawn from therapy; some had accompanying systemic symptoms (e.g., fever, rigors, chills).

Coagulation-positive direct Coombs' test, prolonged prothrombin time, prolonged partial thromboplastin time

Hepatic-transient elevations of AST (SGOT), ALT (SGPT), alkaline phosphatase, bilirubin

Renal-increases in serum creatinine, blood urea nitrogen

Urinalysis-proteinuria, hematuria, pyuria

Additional laboratory events include abnormalities in electrolytes (i.e., increases and decreases in sodium, potassium, and calcium), hyperglycemia, decreases in total protein or albumin, blood glucose decreased, gamma-glutamyltransferase increased, hypokalemia, and bleeding time prolonged.

The following adverse reaction has also been reported for PIPRACIL® (piperacillin for injection):

Skeletal -prolonged muscle relaxation (See PRECAUTIONS: DRUG INTERACTIONS.)

Piperacillin therapy has been associated with an increased incidence of fever and rash in cystic fibrosis patients.

Read the entire FDA prescribing information for Zosyn (Piperacillin and Tazobactam Injection)


Zosyn - User Reviews

Zosyn User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Zosyn sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Women's Health

Find out what women really need.