Zaynich Side Effects and Interactions: What to Expect and How to Manage Them

Written by Beth Johnston, BCPS, PharmD
Medically Reviewed by Patricia Weiser, PharmD on June 09, 2026

Zaynich (cefepime/zidebactam) is a combination antibiotic used to treat complicated urinary tract infections (UTIs), including pyelonephritis.

Like other medicines, Zaynich can cause side effects and interact with other medicines, supplements, or alcohol.

Keep reading to learn about possible Zaynich side effects, how to manage them, and which medicines may interact with Zaynich.

This article does not include all possible side effects or interactions. Tell your health care provider about any symptoms that concern you or do not improve.

Common side effects

The most common side effects reported with Zaynich include:

  • Diarrhea
  • Headache
  • Increased or high blood pressure

Serious side effects

While less common, potentially serious side effects of Zaynich include:

  • Severe skin reactions
  • Central nervous system effects, such as confusion, seizures, or seeing/hearing things that others do not see or hear
  • Antibiotic-associated diarrhea

If you have symptoms that feel serious or life-threatening, seek medical care right away.

While not a complete guide, the following tips can help you prevent or manage possible side effects of Zaynich.

1. Diarrhea

Diarrhea is a common side effect of Zaynich. Possible symptoms include loose or watery stools, stomach cramps, and an urgent need to use the bathroom.

Mild diarrhea often improves on its own within a short time. Tips to help manage diarrhea include:

  • Eat bland foods, such as rice, bananas, or toast.
  • Avoid greasy, spicy, or high-fiber foods that may worsen symptoms.
  • Avoid caffeine and alcohol.
  • Drink fluids often to prevent dehydration. Opt for water, broth, or electrolyte drinks such as Gatorade or Pedialyte.
  • Ask your health care provider if an over-the-counter (OTC) antidiarrheal medicine may help.

 

Diarrhea can sometimes be severe and may require treatment from your health care provider. Certain antibiotics, including Zaynich, can result in an overgrowth of germs called Clostridioides difficile (C. diff). This can lead to severe diarrhea that is hard to treat, known as antibiotic-associated diarrhea. This can happen even up to two months after stopping the antibiotic. Call your health care provider right away if you have any of the following symptoms:

  • Watery diarrhea
  • Diarrhea that does not go away
  • Blood in your stool (poop)
  • Severe stomach cramps
  • A fever that starts after you start or finish the medicine

2. Headache

Headache is a commonly reported side effect of Zaynich. Symptoms may include mild-to-moderate head pain or pressure.

To help manage headaches:

  • Rest in a quiet, dark room if needed.
  • Try relaxation techniques, such as deep breathing.
  • Maintain a regular sleep schedule.
  • Minimize stress.
  • Drink enough fluids throughout the day and eat regular meals or snacks.

An OTC pain reliever may help ease headache pain, but check with your health care provider or pharmacist first to make sure it is safe for you.

3. High blood pressure

An increase in your blood pressure is common with Zaynich. If you already have high blood pressure, your health care provider may need to monitor your blood pressure more closely. 

Blood pressure often rises without causing noticeable symptoms, so monitoring is important. 

Small increases in blood pressure may not be a problem. But if your blood pressure gets too high, you may need medicines to control your blood pressure, a change in your Zaynich dose, or to stop it altogether.

Here are some general suggestions to lower your risk of high blood pressure:

  • Follow a healthy low-fat diet with plenty of fruits and vegetables.
  • Get regular exercise and maintain a healthy weight.
  • Avoid smoking.
  • Limit the amount of alcohol that you drink.
  • Get plenty of sleep and minimize stress.

Zaynich can interact with other medicines. An interaction happens when a substance changes how a medicine works or affects the body. Some interactions may increase the risk of side effects.

When you are being treated with Zaynich, your kidneys help your body get rid of it through your pee. If your kidneys are damaged, your body may not be able to clear Zaynich properly, which can increase your risk of side effects. If your kidneys are not working as well as they should, your health care provider may need to lower your dose of Zaynich. 

This is not a complete list of interactions, but the following are important to note when taking Zaynich.

Diuretics

A diuretic (water pill) is a medicine used to help you get rid of extra fluid and to lower your blood pressure. Using Zaynich with certain diuretics may lead to problems.

Examples of diuretics that may interact with Zaynich include bumetanide and furosemide.

Diuretics help you get rid of extra fluid, which may dehydrate you and keep your kidneys from working as well as they should. Because your kidneys are the main way your body gets rid of Zaynich, your dose may need to be adjusted to keep your blood levels from getting too high and causing side effects.

If you take certain diuretics while you are receiving Zaynich, you may need closer monitoring of your kidney function. Your health care provider will let you know if you need any kidney tests or treatment changes.

Aminoglycosides

An aminoglycoside is a type of antibiotic that is given by injection to treat certain infections.

Examples include:

  • Amikacin
  • Gentamicin
  • Tobramycin

Aminoglycosides can damage your kidneys, affecting how well they function. Your risk for side effects, including from Zaynich or the aminoglycoside, may increase if your kidneys are not working well.

If you are receiving an aminoglycoside while you are getting Zaynich, you may need closer monitoring of your kidney function.

Does Zaynich interact with alcohol?

In general, it is best to limit alcohol consumption to lower your risk of infections. It is unknown if drinking alcohol will affect Zaynich, but alcohol weakens your immune system, making it harder for your body to fight infections.

Does Zaynich interact with lab tests?

Yes, Zaynich can affect the results of certain lab tests. Specifically, if your pee is tested for sugar while using Zaynich, it can lead to a false positive. This means the test will show you have sugar in your pee when you really do not. If any of your health care providers are ordering lab tests, including a urine test, let them know you are using Zaynich. This will help them understand your test results.

You can lower your risk of Zaynich side effects and interactions by following all instructions from your health care provider.

Helpful tips include:

  • Always tell your health care provider and pharmacist about all prescription drugs, OTC medicines, and any vitamins, herbs, or other supplements you use.
  • Ask your health care provider before you start or stop any medicine, vitamin, or supplement.
  • Keep all follow-up appointments and lab tests.
  • Tell any health care provider ordering lab tests that you are using Zaynich.
  • Report any new or worsening symptoms to your health care provider.

Your health care provider can review your treatment plan and make adjustments if needed to help ensure that this medicine is safe for you.

 

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