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Primaxin IM Side Effects

Generic Name: cilastatin / imipenem

Note: This document contains side effect information about cilastatin / imipenem. Some of the dosage forms listed on this page may not apply to the brand name Primaxin IM.

For the Consumer

Applies to cilastatin / imipenem: powder for solution

Along with its needed effects, cilastatin / imipenem may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking cilastatin / imipenem:

More Common

Less Common

  • Dizziness
  • increased sweating
  • nausea or vomiting
  • unusual tiredness or weakness


  • Fever
  • severe abdominal or stomach cramps and pain
  • watery and severe diarrhea, which may also be bloody (these side effects may also occur up to several weeks after you stop receiving this medicine)

Some side effects of cilastatin / imipenem may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More Common

For Healthcare Professionals

Applies to cilastatin / imipenem: injectable powder for injection, intramuscular powder for injection


Imipenem is generally well tolerated.[Ref]


Local side effects associated with IV administration have included phlebitis or thrombophlebitis at the injection site (3.1%), pain at the injection site (0.7%), erythema at the injection site (0.4%), vein induration (0.2%), infused vein infection (0.1%), and injection site reaction.[Ref]


Gastrointestinal side effects have included nausea (2%), vomiting (1.5%), and diarrhea (1.8%). Pseudomembranous colitis, hemorrhagic colitis, gastroenteritis, abdominal pain, glossitis, tongue papillar hypertrophy, staining of the teeth or tongue, heartburn, pharyngeal pain, and increased salivation have been reported in less than 0.2% of patients. Constipation has also been reported.[Ref]

Nervous system

Seizures may be dose-related and are generally reported in patients with renal insufficiency, central nervous system pathology (stroke or neoplasm), or a history of seizure disorder, head trauma, or alcoholism.

A 49-year-old woman with advanced ovarian adenocarcinoma experienced severe myoclonus of the upper extremities while receiving imipenem 500 mg every 6 hours. The myoclonus started to improve within 12 hours of imipenem discontinuation.[Ref]

Neurologic side effects have included seizures (0.4%), dizziness (0.3%), and somnolence (0.2%). Encephalopathy, tremors, confusion, myoclonus, paresthesia, vertigo, headache, psychic disturbances, including hallucinations have been reported in less than 0.2% of patients. Exacerbation of myasthenia gravis has also been reported.[Ref]


Dermatologic side effects have included rash (0.9%), pruritus (0.3%), and urticaria (0.2%). Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, angioneurotic edema, flushing cyanosis, hyperhidrosis, skin texture changes and candidiasis have been reported in less than 0.2% of patients.[Ref]


One study demonstrated an increased incidence of allergic reactions in patients with cystic fibrosis who were given imipenem.[Ref]

Hypersensitivity to imipenem is unusual. However, fever, pruritus, rash, eosinophilia, or positive direct Coombs' test may indicate the presence of hypersensitivity. Patients allergic to other beta-lactam antibiotics may be allergic to imipenem.[Ref]


Cardiovascular side effects have rarely included hypotension, palpitations, and tachycardia.[Ref]


Genitourinary side effects have included pruritus vulvae and urine discoloration in less than 0.2% of patients. Urine protein, red and/or white blood cells, casts, bacteria, bilirubin, and urobilinogen have also been reported.[Ref]


Hematologic side effects have included pancytopenia, bone marrow depression, neutropenia, thrombocytosis, thrombocytopenia, leukopenia, and hemolytic anemia in less than 0.2% of patients. Increased eosinophils, positive Coombs test, increased white blood cells, increased platelets, decreased hemoglobin and hematocrit, anemia, agranulocytosis, increased monocytes, abnormal prothrombin time, increased lymphocytes, and increased basophils have also been reported.[Ref]


Hepatic side effects have included hepatitis (including fulminant hepatitis) and jaundice in less than 0.2% of patients. Transient elevations in liver function tests (ALT, AST, alkaline phosphatase, bilirubin, and LDH) and hepatic failure have also been reported.[Ref]


Metabolic side effects have included decreased serum sodium, increased potassium, and increased chloride.[Ref]


Musculoskeletal side effects have included polyarthralgia in less than 0.2% of patients.[Ref]


Renal side effects have included acute renal failure, oliguria, anuria, and polyuria in less than 0.2% of patients. Increased BUN and creatinine have also been reported.[Ref]


Respiratory side effects have included chest discomfort, dyspnea, hyperventilation, and thoracic spine pain in less than 0.2% of patients.[Ref]


Up to 4% of patients treated with imipenem develop superinfection during therapy. The most common organisms are Enterococcus faecium, Stenotrophomonas maltophilia, methicillin-resistant Staphylococcus aureus, and Candida species.[Ref]

Other side effects have included hearing loss, tinnitus, taste perversion, drug fever, and asthenia/weakness in less than 0.2% of patients. Pain has also been reported.[Ref]


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Further information

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

Some side effects may not be reported. You may report them to the FDA.