imipenem/cilastatin (Rx)

Brand and Other Names:Primaxin
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

imipenem/cilastatin

powder for injection

  • 250mg/250mg
  • 500mg/500mg

Lower Respiratory Tract, Skin/Skin Structure, & Gynecologic Infections

Mild to moderate: 500-750 mg IV q12hr

Intra-abdominal Infections

Mild to moderate: 250-500 mg IV q6hr

Severe: 500 mg IV q6hr or 1 g q8hr for 4-7 days, provided that infection is brought under control

Pseudomonas Infections

500 mg IV q6hr; higher dosages may be administered, depending on organism sensitivity

Urinary Tract Infections

Uncomplicated: 250 mg IV q6hr

Complicated: 500 mg IV q6hr

Dosing Considerations

Dosages are based on imipenem component

Dosages given are for patients weighing >70 kg; use lower dosages in patients weighing <70 kg

Susceptible organisms

  • Acinetobacter spp, Alcaligenes xylosoxidans, Bacteroides spp, Citrobacter spp, Clostridium spp, Enterobacter spp, Escherichia coli, Gardnerella vaginalis, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella spp, Morganella morganii, Nocardia spp, Propionibacterium spp, Proteus vulgaris, Providencia rettgeri, Pseudomonas aeruginosa, Rhodococcus equi, Serratia marcescens, Staphylococcus aureus (penicillinase-producing), Staphylococcus epidermidis, enterococci, group B/D streptococci, Streptococcus pyogenes, Streptococcus pneumoniae

Mild infections (rarely used)

  • Fully susceptible organisms: 250 mg IV q6hr
  • Moderately susceptible organisms: 500 mg IV q6hr

Moderate infections

  • IV: Fully susceptible organisms: 500 mg IV q6-8hr
  • Moderately susceptible organisms: 500 mg IV q6hr or 1 g IV q8hr

Severe infections

  • Fully susceptible organisms: 500 mg IV q6hr
  • Moderately susceptible organisms: 1 g IV q6-8hr; not to exceed 50 mg/kg/day or 4 g/day, whichever is lower

Dosing Modifications

Renal impairment

  • CrCl ≥71 mL/min/1.73 m²: 250 mg IV q6hr
  • CrCl 41-70 mL/min/1.73m²: 250 mg IV q8hr
  • CrCl 21-40 mL/min/1.73 m²: 125-250 mg IV q12hr
  • CrCl ≤20 mL/min/1.73 m²: 125-250 mg IV q12hr
  • CrCl <5 mL/min/1.73 m²: Use IV only if hemodialysis is instituted within 48 hours
  • Hemodialysis: Give supplemental dose after each dialysis, then q12hr

Dosage Forms & Strengths

imipenem/cilastatin

powder for injection

  • 250mg/250mg

Dosages based on imipenem component

<1 week, >1.5 kg: 25 mg/kg IV q12hr for non-CNS infections  

1-4 weeks, >1.5 kg: 25 mg/kg IV q8hr for non-CNS infections

4 weeks-3 months, >1.5 kg: 25 mg/kg IV q6hr for non-CNS infections

>3 months: 15-25 mg/kg IV q6hr for non-CNS infections; not to exceed 2 g/day for fully susceptible organisms or 4 g/day for moderately susceptible organisms

>12 years: 10-15 mg/kg IV q6hr for mild-to-moderate infections

Cystic fibrosis patients: Up to 100 mg/kg/day IV divided q6hr; not to exceed 4 g/day (in older children)

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Interactions

Interaction Checker

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    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

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            Contraindicated (0)

              Serious - Use Alternative (7)

              • BCG intravesical live

                imipenem/cilastatin decreases effects of BCG intravesical live by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Intravesical BCG prescribing information states that antimicrobial therapy for other infections may interfere with the effectiveness of BCG intravesical. Antibiotics with activity against mycobacteria are of the greatest concern; however, avoiding all antimicrobial therapy during treatment is currently recommended.

              • cholera vaccine

                imipenem/cilastatin decreases effects of cholera vaccine by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.

              • divalproex sodium

                imipenem/cilastatin will decrease the level or effect of divalproex sodium by unknown mechanism. Avoid or Use Alternate Drug. Data from in vitro and animal studies suggest carbapenems may inhibit hydrolysis of the valproic acid glucuronide metabolite (VPA-g) back to valproic acid, thus decreasing the serum concentrations of valproic acid/divalproex sodium.

              • ganciclovir

                ganciclovir, imipenem/cilastatin. unknown mechanism. Avoid or Use Alternate Drug. Coadministration may increase risk of seizures. Avoid unless potential benefit outweighs the risk.

              • probenecid

                probenecid increases levels of imipenem/cilastatin by decreasing renal clearance. Avoid or Use Alternate Drug. Coadministration increases the plasma level and half-life of imipenem.

              • valacyclovir

                valacyclovir, imipenem/cilastatin. unknown mechanism. Avoid or Use Alternate Drug. Coadministration may increase risk of seizures. Avoid unless potential benefit outweighs the risk.

              • valproic acid

                imipenem/cilastatin will decrease the level or effect of valproic acid by unknown mechanism. Avoid or Use Alternate Drug. Data from in vitro and animal studies suggest carbapenems may inhibit hydrolysis of the valproic acid glucuronide metabolite (VPA-g) back to valproic acid, thus decreasing the serum concentrations of valproic acid/divalproex sodium.

              Monitor Closely (5)

              • BCG vaccine live

                imipenem/cilastatin decreases effects of BCG vaccine live by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. BCG vaccine prescribing information states that antimicrobial or immunosuppressive agents may interfere with the development of the immune response and should be used only under medical supervision.

              • cyclosporine

                cyclosporine, imipenem/cilastatin. Other (see comment). Use Caution/Monitor. Comment: Cyclosporine may increase the neurotoxic effects of imipenem. Cases reports describe imipenem increasing or decreasing cyclosporine serum concentration levels.

              • sodium picosulfate

                imipenem/cilastatin decreases effects of sodium picosulfate by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.

              • sodium picosulfate/magnesium oxide/anhydrous citric acid

                imipenem/cilastatin decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.

              • typhoid vaccine live

                imipenem/cilastatin decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Postpone administering vaccine until at least 3 days after completing antibiotic regimen.

              Minor (0)

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                Adverse Effects

                1-10%

                Phlebitis (2-5%)

                Eosinophilia (4%)

                Miscellaneous dermatologic effects (<3%)

                Potentially false-positive Coombs test (2%)

                Miscellaneous hematologic effects (<2%)

                Transient increase in blood urea nitrogen (BUN) or serum creatinine (<2%)

                Seizures (1.5%)

                Nausea, diarrhea, vomiting (1-2%)

                <1%

                Abnormal urinalysis

                Agitation

                Anaphylaxis

                Anemia

                Confusion (acute)

                Dizziness

                Dyskinesia

                Emergence of resistant strains of Pseudomonas aeruginosa

                Fever

                Hypersensitivity

                Hypotension

                Elevated liver function test (LFT) results

                Increased prothrombin time (PT)

                Neutropenia (including agranulocytosis)

                Palpitations

                Pruritus

                Pseudomembranous colitis

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                Warnings

                Contraindications

                Hypersensitivity to imipenem or cilastatin

                Cautions

                History of hypersensitivity to penicillins

                Use with caution in CNS disorders (eg., history of seizures); adjust dosage in renal impairment to avoid risk of seizures; carbapenem use has been associated with seizures

                Prolonged use increases risk of superinfections

                Use with caution in renal impairment; adjust dosage in moderate to severe renal dysfunction

                Carbapenem use may decrease serum levels of divalproex sodium or valproic acid

                Combination with aminoglycosides may thwart resistant P aeruginosa

                Not for use in children with CNS problems

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                Pregnancy & Lactation

                Pregnancy

                Available data from a small number of postmarketing cases in pregnancy are not sufficient to identify any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes

                Animal data

                • Developmental toxicity studies with imipenem and cilastatin sodium (alone or in combination) administered to mice, rats, rabbits, and monkeys at doses 0.4 to 2.9 times the recommended human dose (RHD), (based on body surface area), showed no drug-induced fetal malformations
                • Embryofetal development studies with imipenem/cilastatin administered to cynomolgus monkeys at doses similar to RHD (based on body surface area) showed an increase in embryonic loss

                Lactation

                There are insufficient data on presence of imipenem/cilastatin in human milk, and no data on effects on breastfed child, or on milk production; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed child from therapy or from the underlying maternal condition

                Pregnancy Categories

                A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

                B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

                C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

                D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

                X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

                NA: Information not available.

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                Pharmacology

                Mechanism of Action

                Imipenem inhibits bacterial cell-wall synthesis by binding to penicillin-binding proteins; cilastatin prevents renal metabolism of imipenem

                Distribution

                Distributed rapidly and widely to most tissues and fluids, including sputum, pleural fluid, peritoneal fluid, interstitial fluid, bile, aqueous humor, reproductive organs, and bone; highest concentrations in pleural fluid, interstitial fluid, peritoneal fluid, and reproductive organs; low concentrations in CSF; crosses placenta; enters breast milk

                Protein bound: Imipenem, 13-21%; cilastatin, 40%

                Metabolism

                Imipenem is metabolized in the kidney by dehydropeptidase 1; activity is blocked by cilastatin

                Elimination

                Half-life (both drugs): 60 min; prolonged with renal impairment

                Excretion (both drugs): Urine (~70% as unchanged drug)

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                Administration

                IV Incompatibilities

                Solution: D5/LR, LR, sodium bicarbonate, sodium lactate (D5W and NS causes some activity loss but are recommended for short-term use)

                Y-site: Allopurinol, amiodarone, amphotericin B cholesteryl sulfate, azithromycin, etoposide phosphate, fluconazole, gemcitabine, lorazepam, meperidine, midazolam, sargramostim, sodium bicarbonate

                IV Preparation

                Reconstitute infusion bottles with 100 mL of compatible diluent

                Reconstitute vials with a portion (usually 10 mL) of IV fluid withdawn from the IV container, dissolve, and return to container; repeat

                Reconstituted solutions are stable for 4 hours at room temperature and 24 hours refrigerated (4 C) in NS

                Normal color ranges from clear to yellow; these variations do not affect potency, but solution should be discarded if brown

                Imipenem is inactivated at acidic or alkaline pH

                IV Administration

                Do not administer by IV push

                Final concentration should not exceed 5 mg/mL

                Infuse ≤500 mg over 20-30 minutes (15-30 minutes in children); infuse >500 mg over 40-60 min

                Vial contents must be transferred to 100 mL of infusion solution

                If nausea or vomiting occurs during administration, reduce infusion rate

                Drug must not be mixed or physically added to other antibiotics; however, it may be administered concomitantly

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                Images

                BRAND FORM. UNIT PRICE PILL IMAGE
                Primaxin intravenous
                -
                500 mg vial
                imipenem-cilastatin intravenous
                -
                250 mg vial
                imipenem-cilastatin intravenous
                -
                500 mg vial
                imipenem-cilastatin intravenous
                -
                250 mg vial
                imipenem-cilastatin intravenous
                -
                500 mg vial
                imipenem-cilastatin intravenous
                -
                250 mg vial
                imipenem-cilastatin intravenous
                -
                500 mg vial

                Copyright © 2010 First DataBank, Inc.

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                Patient Handout

                Patient Education
                imipenem-cilastatin intravenous

                IMIPENEM/CILASTATIN - INJECTION

                (IM-i-PEM-em/SYE-la-STAT-in)

                COMMON BRAND NAME(S): Primaxin

                USES: This medication is used to treat a wide variety of bacterial infections. This medication is known as a carbapenem-type antibiotic. It works by stopping the growth of bacteria.

                HOW TO USE: This medication is given by injection into a muscle or vein, usually every 6 to 8 hours or as directed by your doctor. The dosage is based on your medical condition and response to treatment.If you are giving this medication to yourself at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.For the best effect, use this antibiotic at evenly spaced times. To help you remember, use this medication at the same time(s) every day.Continue to use this medication until the full prescribed treatment period is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.Tell your doctor if your condition persists or worsens.

                SIDE EFFECTS: Swelling, redness, pain, or soreness at the injection site may occur. This medication may also rarely cause upset stomach, nausea, vomiting, or diarrhea. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: dark urine, easy bruising/bleeding, hearing changes (e.g., decreased hearing, ringing in the ears), mental/mood changes (e.g., confusion, hallucinations), persistent sore throat/fever, tingling hands/feet, yellowing eyes/skin, muscle twitching/spasms.Get medical help right away if any of these rare but very serious side effects occur: seizures, unusual weakness.This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn't stop, abdominal or stomach pain/cramping, blood/mucus in your stool.If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

                PRECAUTIONS: Before using imipenem with cilastatin, tell your doctor or pharmacist if you are allergic to either of its ingredients; or to other carbapenems (such as meropenem); or to penicillins or cephalosporins; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: brain disorders (e.g., seizures, head injury, tumor), kidney disease, liver disease, stomach/intestinal diseases (e.g., colitis).This medication may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to.Kidney function declines as you grow older. This medication is removed by the kidneys. Elderly people may be at greater risk for side effects while using this drug.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This medication passes into breast milk. Though there have been no reports of harm to nursing infants, consult your doctor before breast-feeding.

                DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: ganciclovir, valproic acid and related drugs (such as divalproex sodium, sodium valproate).This medication may interfere with certain laboratory tests (e.g., urine glucose), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

                OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: seizures.

                NOTES: Do not share this medication with others.This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.Laboratory and/or medical tests (e.g., complete blood count, kidney/liver function tests) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

                MISSED DOSE: It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule. Do not double the dose to catch up.

                STORAGE: Consult the product instructions and your pharmacist for storage details. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

                Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

                IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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                Formulary

                FormularyPatient Discounts

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                The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

                Tier Description
                1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
                2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
                3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
                4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
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                NC NOT COVERED – Drugs that are not covered by the plan.
                Code Definition
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                Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.