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Overview: Imipenem/cilastatin is an antibiotic that is used for infections caused by certain bacteria. Common side effects are pain and redness at the injection site, nausea, vomiting, diarrhea, fever, dizziness, and drowsiness. Tell your health care provider if you are taking seizure medicine or have a history of seizures before starting imipenem/cilastatin. Talk to your health care provider right away if you develop severe diarrhea, even several months after stopping the medicine.

Uses

What is imipenem/cilastatin used for?

Imipenem/cilastatin is an antibiotic that is commonly used to treat the following serious infections caused by certain bacteria.

Imipenem/cilastatin may not be appropriate for some of the infections listed above, depending on which germs are causing the infection. Bacteria in some locations may have developed resistance to imipenem/cilastatin, which will make it not work as well.

Imipenem/cilastatin may also be used for other conditions as determined by your health care provider.

How does imipenem/cilastatin work (mechanism of action)?

Imipenem kills certain types of bacteria by blocking their ability to create their cell wall. Cilastatin works to keep imipenem in the body longer.

How is imipenem/cilastatin supplied (dosage forms)?

Brands and other names

  • Primaxin

Dosage forms and strengths

Imipenem/cilastatin is available in an injectable form that is given by a health care provider.

How should I store imipenem/cilastatin?

Imipenem/cilastatin is usually given by a health care provider in a hospital or clinic. You will not store it at home.

Side Effects

What are the most common side effects of imipenem/cilastatin?

The most common side effects of imipenem/cilastatin are listed below. These side effects may vary based on the age of the person being treated. Tell your health care provider if you have any of these side effects that bother you. 

  • Pain, itching, hardness, and swelling or redness near the injection site
  • Nausea, vomiting, diarrhea
  • Rash or itching
  • Fever
  • Low blood pressure
  • Seizures (see below)
  • Dizziness and drowsiness
  • Stomach flu (gastroenteritis)
  • Changes in urine (pee), including the amount and color of pee
  • Oral thrush (candidiasis)
  • Fast heartbeat

There may be other side effects of imipenem/cilastatin that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of imipenem/cilastatin?

While less common, the most serious side effects of imipenem/cilastatin are described below, along with what to do if they happen.

Severe Allergic Reactions. Imipenem/cilastatin may cause allergic reactions, which can be serious. Stop using imipenem/cilastatin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Seizures. Some people who have used imipenem/cilastatin have reported having seizures and confusion. This happens most often in people who have a history of seizures, kidney problems, or other brain conditions. People who take certain medicines to treat a seizure disorder may also be at an increased risk for seizures while using imipenem/cilastatin. There are many types of seizures and some of them are not easy to recognize. Tell your health care provider if you have any of the following signs that a seizure is happening or could happen.

  • Muscle twitching, jerking, spasms, tremors, or other uncontrolled movements
  • Stiffening of your arms and legs
  • Feeling anxious, nervous, confused, or a sense of dread
  • Feeling dizzy or lightheaded
  • Falling or losing consciousness

Antibiotic-associated Diarrhea. An overgrowth of germs called Clostridioides difficile, or C. diff, can happen in your gut with many types of antibiotics, including imipenem/cilastatin. This can cause a condition known as antibiotic-associated diarrhea and can happen two or more months after stopping the antibiotic. Tell your health care provider right away if you have any of the following symptoms of this condition.

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

Warnings & Precautions

Who should not use imipenem/cilastatin?

Allergies to Ingredients. People who are allergic to any of the following should not use imipenem/cilastatin.

  • Imipenem/cilastatin
  • Primaxin
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific imipenem/cilastatin products they stock.

What should I know about imipenem/cilastatin before using it?

Imipenem/cilastatin is usually given by a health care provider in a hospital or clinic.

Imipenem/cilastatin can increase your risk of seizures and confusion. See the Side Effects section for more details. If you have a history of seizures, it is important that you take any seizure medicine as prescribed while using imipenem/cilastatin. Do not drive or do other activities that require alertness or coordination until you know how imipenem/cilastatin affects you.

What should I tell my health care provider before using imipenem/cilastatin?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if imipenem/cilastatin is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Seizures
  • Stroke
  • Kidney problems
  • Allergy to an antibiotic, especially a penicillin or cephalosporin

Other Medicines and Supplements. Imipenem/cilastatin may interact with other medicines and supplements. Before using imipenem/cilastatin, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how imipenem/cilastatin could affect pregnancy or harm an unborn baby. Tell your health care provider if you are or plan to become pregnant.

Breastfeeding. It is unknown if imipenem/cilastatin passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will advise you if you should use imipenem/cilastatin while breastfeeding.

Interactions

Does imipenem/cilastatin interact with foods or drinks?

There are no known interactions between imipenem/cilastatin and foods or drinks. 

It is unknown if drinking alcohol will affect imipenem/cilastatin, but heavy drinking can slow your immune response and make it harder for your body to fight infection. Both alcohol and imipenem/cilastatin can cause confusion. It is best to limit the amount of alcohol you drink while using imipenem/cilastatin.

Does imipenem/cilastatin interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. 

In particular, make sure that you discuss if you are using any of the following before using imipenem/cilastatin. 

  • Ganciclovir, which is a medicine used to treat certain viral infections caused by a virus called cytomegalovirus (CMV) 
  • Probenecid, which is a medicine commonly used for gout
  • Valproic acid, divalproex sodium, and valproate sodium (Depakote and others), which is a medicine used for seizures and other conditions

This may not be a complete list of medicines that can interact with imipenem/cilastatin. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much imipenem/cilastatin?

If you or someone else has used too much imipenem/cilastatin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of imipenem/cilastatin?

Imipenem/cilastatin is usually given by a health care provider in a hospital. Your health care provider will make sure you are receiving imipenem/cilastatin as scheduled. 

It is important to complete your prescribed course of imipenem/cilastatin, even if your symptoms get better or go away. This will reduce the risk that future infections are resistant to imipenem/cilastatin or other similar medicines.