Get emergency medical help if you have signs of an allergic reaction to Zosyn (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.
To make sure Zosyn is safe for you, tell your doctor if you have ever had:
severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);
confusion;
muscle twitching or stiffness, trouble walking;
a seizure;
low white blood cell counts: may experience fever, mouth sores, skin sores, sore throat, cough, trouble breathing; or
low potassium: may experience leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.
Common Zosyn side effects 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.
 Zosyn side effects (more detail)
