Flagyl vs. Zosyn

Flagyl, Flagyl ER, and Flagyl Injection (metronidazole) and Zosyn (piperacillin and tazobactam for injection) are antibiotics used to treat bacterial infections.

Flagyl and Zosyn are different types of antibiotics. Flagyl is a nitroimidazole antibiotic and Zosyn is a combination of a penicillin-class antibacterial and a beta-lactamase inhibitor.

Side effects of Flagyl include:

• nausea,
• abdominal cramps,
• stomach upset,
• vomiting,
• diarrhea,
• constipation,
• headache,
• weight loss (anorexia),
• dizziness,
• dry mouth,
• dark-colored urine, or
• a metallic taste in the mouth or changes in taste.

Uncomfortable side effects that may become serious are:

• fevers,
• pain with urination,
• mouth sores,
• tingling or pricking sensations that may become permanent,
• brain disease, and
• seizures.

Serious but unlikely side effects of Flagyl include:

• unsteadiness,
• seizures,
• mood changes,
• numbness or tingling of the hands or feet, and
• painful urination.

Common side effects of Zosyn include:

• injection site reactions like
  • swelling,
  • redness,
  • pain,
  • soreness or
  • irritation;
• 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.

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

Flagyl, Flagyl ER, and Flagyl Injection (metronidazole) are antimicrobial drugs used to treat bacterial vaginosis, trichomonas, amebiasis, and anaerobic bacterial infections.

What is Zosyn?

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..

Flagyl may interact with blood thinners or seizure medications.

Flagyl may also interact with cimetidine, lithium, or disulfiram.

Zosyn may interact with medication to prevent blood clots, probenecid, or other antibiotic.

Flagyl is supplied in 250 and 500 mg strength tablets, Flagyl ER is available in 750 mg strength tablets, and Flagyl Injection in 500 mg strength in a buffered 100 ml vial. Dosage is quite variable and dependent upon the severity of disease and other considerations made by the treating physician. Most of the serious side effects may occur with any of these three preparations of Flagyl. Flagyl may cause liver enzyme levels to increase; lithium and creatinine levels should be checked to avoid lithium toxicity or renal compromise. Alcohol may increase the side effects of Flagyl. Patients on disulfiram should not take Flagyl until they have had a two week interval without taking disulfiram, especially alcoholic patients, to avoid psychotic reactions. Treatment in pregnant women (during first 3 months is not advised) or women who are breastfeeding should only be done if the benefits outweigh the potential problems. Flagyl passes into breast milk and may harm a nursing baby. Consult your doctor before breastfeeding. Except for use in amebiasis, studies in pediatric patients are not available; Flagyl ER has no pediatric studies.

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).