August 27, 2016
Recommended Topic Related To:

Zosyn Injection

"The U.S. Food and Drug Administration today approved Impavido (miltefosine) to treat a tropical disease called leishmaniasis.

Leishmaniasis is a disease caused by Leishmania, a parasite which is transmitted to humans through sand fly bites."...


Zosyn Injection

Side Effects


Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

During the initial clinical investigations, 2621 patients worldwide were treated with ZOSYN in phase 3 trials. In the key North American monotherapy 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%).

Table 3: Adverse Reactions from ZOSYN Monotherapy Clinical Trials System Organ Class

System Organ Class
Adverse Reaction
Gastrointestinal disorders
  Diarrhea (11.3%)
  Constipation (7.7%)
  Nausea (6.9%)
  Vomiting (3.3%)
  Dyspepsia (3.3%)
  Abdominal pain (1.3%)
  Pseudomembranous colitis ( ≤ 1%)
General disorders and administration site conditions
  Fever (2.4%)
  Injection site reaction ( ≤ 1%)
  Rigors ( ≤ 1%)
Immune system disorders
  Anaphylaxis ( ≤ 1%)
Infections and infestations
  Candidiasis (1.6%)
Metabolism and nutrition disorders
  Hypoglycemia ( ≤ 1%)
Musculoskeletal and connective tissue disorders
  Myalgia ( ≤ 1%)
  Arthralgia ( ≤ 1%)
Nervous system disorders
  Headache (7.7%)
  Insomnia (6.6%)
Skin and subcutaneous tissue disorders
  Rash (4.2%, including maculopapular, bullous, and urticarial)
  Pruritus (3.1%)
Vascular disorders
  Phlebitis (1.3%)
  Thrombophlebitis ( ≤ 1%)
  Hypotension ( ≤ 1%)
  Purpura ( ≤ 1%)
  Epistaxis ( ≤ 1%)
  Flushing ( ≤ 1%)

Nosocomial Pneumonia Trials

Two trials of nosocomial lower respiratory tract infections were conducted. In one study, 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.

The second trial used a dosing regimen of 3.375 g given every 4 hours with an aminoglycoside.

Table 4: Adverse Reactions from ZOSYN Plus Aminoglycoside Clinical Trialsa

System Organ Class Adverse Reaction  
Blood and lymphatic system disorders
  Thrombocythemia (1.4%)
  Anemia ( ≤ 1%)
  Thrombocytopenia ( ≤ 1%)
  Eosinophilia ( ≤ 1%)
Gastrointestinal disorders
  Diarrhea (20%)
  Constipation (8.4%)
  Nausea (5.8%)
  Vomiting (2.7%)
  Dyspepsia (1.9%)
  Abdominal pain (1.8%)
  Stomatitis ( ≤ 1%)
General disorders and administration site conditions
  Fever (3.2%)
  Injection site reaction ( ≤ 1%)
Infections and infestations
  Oral candidiasis (3.9%)
  Candidiasis (1.8%)
  BUN increased (1.8%)
  Blood creatinine increased (1.8%)
  Liver function test abnormal (1.4%)
  Alkaline phosphatase increased ( ≤ 1%)
  Aspartate aminotransferase increased ( ≤ 1%)
  Alanine aminotransferase increased ( ≤ 1%)
Metabolism and nutrition disorders
  Hypoglycemia ( ≤ 1%)
  Hypokalemia ( ≤ 1%)
Nervous system disorders
  Headache (4.5%)
  Insomnia (4.5%)
Renal and urinary disorders
  Renal failure ( ≤ 1%)
Skin and subcutaneous tissue disorders
  Rash (3.9%)
  Pruritus (3.2%)
Vascular disorders
  Thrombophlebitis (1.3%)
  Hypotension (1.3%)
aFor adverse drug reactions that appeared in both studies the higher frequency is presented


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.

Adverse Laboratory Events (Seen During Clinical Trials)

Of the trials reported, including that of nosocomial lower respiratory tract infections in which a higher dose of ZOSYN was used in combination with an aminoglycoside, changes in laboratory parameters include:

Hematologic—decreases in hemoglobin and hematocrit, thrombocytopenia, increases in platelet count, eosinophilia, leukopenia, neutropenia. 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

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.

Post-Marketing Experience

In addition to the adverse drug reactions identified in clinical trials in Table 3 and Table 4, the following adverse reactions have been identified during postapproval use of ZOSYN.

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish causal relationship to drug exposure.

Gastrointestinal—hepatitis, jaundice

Hematologic—hemolytic anemia, agranulocytosis, pancytopenia

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

Renal—interstitial nephritis

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

Additional Experience with piperacillin

The following adverse reaction has also been reported for piperacillin for injection:

Skeletal—prolonged muscle relaxation [see DRUG INTERACTIONS].

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

Read the Zosyn Injection (piperacillin and tazobactam pharmacy bulk vial) Side Effects Center for a complete guide to possible side effects



Piperacillin may inactivate aminoglycosides by converting them to microbiologically inert amides.

In vivo inactivation: When aminoglycosides are administered in conjunction with piperacillin to patients with end-stage renal disease requiring hemodialysis, the concentrations of the aminoglycosides (especially tobramycin) may be significantly reduced and should be monitored.

Sequential administration of ZOSYN and tobramycin to patients with either normal renal function or mild to moderate renal impairment has been shown to modestly decrease serum concentrations of tobramycin but no dosage adjustment is considered necessary.

In vitro inactivation: Due to the in vitro inactivation of aminoglycosides by piperacillin, ZOSYN and aminoglycosides are recommended for separate administration. ZOSYN and aminoglycosides should be reconstituted, diluted, and administered separately when concomitant therapy with aminoglycosides is indicated. ZOSYN, which contains EDTA, is compatible with amikacin and gentamicin for simultaneous Y-site infusion in certain diluents and at specific concentrations. ZOSYN is not compatible with tobramycin for simultaneous Y-site infusion [see DOSAGE AND ADMINISTRATION].


Probenecid administered concomitantly with ZOSYN prolongs the half-life of piperacillin by 21% and that of tazobactam by 71% because probenecid inhibits tubular renal secretion of both piperacillin and tazobactam. Probenecid should not be co-administered with ZOSYN unless the benefit outweighs the risk.


Coagulation parameters should be tested more frequently and monitored regularly during simultaneous administration of high doses of heparin, oral anticoagulants, or other drugs that may affect the blood coagulation system or the thrombocyte function. [see WARNINGS AND PRECAUTIONS]


Piperacillin when used concomitantly with vecuronium has been implicated in the prolongation of the neuromuscular blockade of vecuronium. ZOSYN could produce the same phenomenon if given along with vecuronium. Due to their similar mechanism of action, it is expected that the neuromuscular blockade produced by any of the non-depolarizing muscle relaxants could be prolonged in the presence of piperacillin. Monitor for adverse reactions related to neuromuscular blockade (See package insert for vecuronium bromide).


Limited data suggests that co-administration of methotrexate and piperacillin may reduce the clearance of methotrexate due to competition for renal secretion. The impact of tazobactam on the elimination of methotrexate has not been evaluated. If concurrent therapy is necessary, serum concentrations of methotrexate as well as the signs and symptoms of methotrexate toxicity should be frequently monitored.

Effects on Laboratory Tests

There have been reports of positive test results using the Bio-Rad Laboratories Platelia Aspergillus EIA test in patients receiving piperacillin/tazobactam injection who were subsequently found to be free of Aspergillus infection. Cross-reactions with non-Aspergillus polysaccharides and polyfuranoses with the Bio-Rad Laboratories Platelia Aspergillus EIA test have been reported. Therefore, positive test results in patients receiving piperacillin/tazobactam should be interpreted cautiously and confirmed by other diagnostic methods.

As with other penicillins, the administration of ZOSYN may result in a false-positive reaction for glucose in the urine using a copper-reduction method (CLINITEST®). It is recommended that glucose tests based on enzymatic glucose oxidase reactions be used.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 9/19/2013

Side Effects

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.