Generic name: piperacillin and tazobactam [ PI-per-a-SIL-in-and-TAZ-oh-BAK-tam ]
Brand name: Zosyn
Dosage forms: intravenous powder for injection (12 g-1.5 g; 2 g-0.25 g; 3 g-0.375 g; 36 g-4.5 g; 4 g-0.5 g), ... show all 2 dosage forms intravenous solution (2 g-0.25 g/50 mL; 3 g-0.375 g/50 mL; 4 g-0.5 g/100 mL)
Drug class: Penicillins / beta-lactamase inhibitors

Medically reviewed by Drugs.com on Nov 4, 2025. Written by Cerner Multum.

What is piperacillin and tazobactam?

Piperacillin and tazobactam is a combination penicillin antibiotic that is used to treat many bacterial infections, such as stomach infections, skin infections, pneumonia, and severe uterine infections.

piperacillin and tazobactam is sometimes given together with other antibiotics.

Piperacillin and tazobactam may also be used for purposes not listed in this medication guide.

Piperacillin and tazobactam side effects

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

Piperacillin and tazobactam may cause serious side effects. Call your doctor at once if you have:

• severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);

• unusual bleeding, easy bruising, fever, mouth sores, skin sores, sore throat, cough, trouble breathing, swollen lymph nodes, rash;

• a seizure;

• low blood cell counts;

• swelling or tenderness in the stomach area;

• kidney problems--swelling, urinating less, feeling tired or short of breath; or

• low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Common side effects of piperacillin and tazobactam may include:

• diarrhea, constipation;

• nausea;

• headache; or

• sleep problems (insomnia).

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.

Warnings

Use only as directed. Tell your doctor if you use other medicines or have other medical conditions or allergies.

Before taking this medicine

You should not use piperacillin and tazobactam if you are allergic to piperacillin and tazobactam or similar medicines such as:

• amoxicillin (Amoxil, Augmentin), ampicillin, penicillin, and others;

• cefuroxime, cefdinir, cefepime, ceftriaxone, cephalexin, and others; or

• clavulanate (clavulanic acid), tazobactam, sulbactam, avibactam, vaborbactam relebactam, and others.

Tell your doctor if you have or have ever had:

• a bleeding or blood clotting disorder;

• an electrolyte imbalance such as low levels of potassium in your blood;

• cystic fibrosis;

• epilepsy or other seizure disorder;

• you have a planned surgery or procedure where anesthesia may be used;

• any type of allergy;

• if you are on a low-salt diet; or

• kidney disease (or if you are on dialysis).

Tell your doctor if you are pregnant or breastfeeding.

How should I use piperacillin and tazobactam?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Piperacillin and tazobactam is given as an infusion into a vein. A healthcare provider may give you this injection or may teach you how to properly use this medicine by yourself. Your doctor will determine the right treatment schedule for you.

Read and carefully follow any Instructions for Use provided with your medicine. Prepare an injection only when you are ready to give it. Call your pharmacist if the medicine looks cloudy, has changed colors or has particles in it. Ask your doctor or pharmacist if you don't understand how to use an injection.

Be sure you understand how to properly mix this medicine with a liquid (diluent) and how to store the mixture.

Keep using this medicine even if your symptoms quickly improve. Skipping doses could make your infection resistant to medication. Piperacillin and tazobactam will not treat a viral infection (flu or a common cold).

Depending on the severity of the infection, piperacillin and tazobactam is usually given for as long as needed until lab tests show that the infection has cleared. Your doctor will determine how long to treat you with this medicine.

Your doctor will need to check your progress on a regular basis. Your blood and kidney function may need to be tested often.

Antibiotic medicines can cause diarrhea. Tell your doctor if you have diarrhea that is watery or bloody.

Doses are based on weight in children and teenagers. Your child's dose may change if the child gains or loses weight.

This medicine may affect the results of certain medical tests. Tell any doctor or laboratory staff who treats you that you are using piperacillin and tazobactam.

Follow all storage instructions provided with piperacillin and tazobactam. Your pharmacist can provide more information about how to store this medicine.

Related/similar drugs

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using piperacillin and tazobactam?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect piperacillin and tazobactam?

Tell your doctor about all your other medicines, especially:

• probenecid;

• a blood thinner--warfarin, Coumadin, Jantoven;

• vancomycin;

• a diuretic or "water pill"; or

• cancer medicine.

This list is not complete. Other drugs may affect piperacillin and tazobactam, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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