- Imipenem and Cilastatin for Injection (I.V.), as supplied in single dose vials and reconstituted with the appropriate diluents
[see Dosage and Administration (
2.5)]
, maintains satisfactory potency for 4 hours at room temperature or for 24 hours under refrigeration (5°C). Do not freeze solutions of Imipenem and Cilastatin for Injection (I.V.).
Adult Patients
During clinical investigations 1,723 patients were treated with Imipenem and Cilastatin for Injection (I.V.).
Table 4 shows the incidence of adverse reactions reported during the clinical investigations of adult patients treated with Imipenem and Cilastatin for Injection (I.V.).
Table 4: Incidence (%)* of Adverse Reactions Reported During Clinical Investigations of Adult Patients Treated with Imipenem and Cilastatin for Injection (I.V.)
|
| Body System | Adverse Reactions | Frequency (%) |
| Local Administration site
| Phlebitis/ thrombophlebitis
| 3.1%
|
| Pain at the injection site
| 0.7%
|
| Erythema at the injection site
| 0.4%
|
| Vein induration
| 0.2%
|
| Gastrointestinal
| Nausea
| 2%
|
| Diarrhea
| 1.8%
|
| Vomiting
| 1.5%
|
| Skin
| Rash
| 0.9%
|
| Pruritus
| 0.3%
|
| Urticaria
| 0.2%
|
| Vascular
| Hypotension
| 0.4%
|
| Body as a Whole
| Fever
| 0.5%
|
| Nervous system
| Seizures
| 0.4%
|
| Dizziness
| 0.3%
|
| Somnolence
| 0.2%
|
Additional adverse reactions reported in less than 0.2% of the patients or reported since the drug was marketed are listed within each body system in order of decreasing severity
[see
Table 5].
Table 5: Additional Adverse Reactions Occurring in Less than 0.2% of Adult Patients Listed within Each Body System in Order of Decreasing Severity
| Body System | Adverse Reactions |
| Gastrointestinal
| Pseudomembranous Colitis (the onset of Pseudomembranous colitis symptoms), Hemorrhagic Colitis
|
|
| Gastroenteritis
|
| Abdominal Pain
|
| Glossitis
|
| Tongue Papillar
|
| Hypertrophy
|
| Heartburn
|
| Pharyngeal Pain
|
| Increased Salivation
|
| CNS
| Encephalopathy
|
| Confusion
|
| Myoclonus
|
| Paresthesia
|
| Vertigo
|
| Headache
|
| Special Senses
| Hearing Loss
|
| Tinnitus
|
| Respiratory
| Chest Discomfort
|
| Dyspnea
|
| Hyperventilation
|
| Thoracic Spine Pain
|
| Cardiovascular
| Palpitations
|
| Tachycardia
|
| Skin
| Erythema Multiforme
|
| Angioneurotic Edema
|
| Flushing
|
| Cyanosis
|
| Hyperhidrosis
|
| Skin Texture Changes
|
| Candidiasis
|
| Pruritus Vulvae
|
| Local Administration site
| Infused vein infection
|
| Body as a Whole
| Polyarthralgia
|
| Asthenia/Weakness
|
| Renal
| Oliguria/Anuria
|
| Polyuria
|
Adverse Laboratory Changes
The following adverse laboratory changes were reported during clinical trials:
Hepatic: Increased alanine aminotransferase (ALT or SGPT), aspartate aminotransferase (AST or SGOT), alkaline phosphatase, bilirubin, and lactate dehydrogenase (LDH)
Hemic: Increased eosinophils, positive Coombs test, increased WBC, increased platelets, decreased hemoglobin and hematocrit, increased monocytes, abnormal prothrombin time, increased lymphocytes, increased basophils
Electrolytes: Decreased serum sodium, increased potassium, increased chloride
Renal: Increased BUN, creatinine
Urinalysis: Presence of urine protein, urine red blood cells, urine white blood cells, urine casts, urine bilirubin, and urine urobilinogen.
Pediatric Patients
Table 6: Incidence (%)* of Adverse Reactions Reported During Clinical Investigations of Pediatric Patients Greater Than or Equal to 3 Months of Age Treated with Imipenem and Cilastatin for Injection (I.V.)
|
| Body System | Adverse Reactions | Frequency (%) |
| Local Administration Site
| Phlebitis
| 2.2%
|
| Intravenous Site Irritation
| 1.1%
|
| Gastrointestinal
| Diarrhea
| 3.9%
|
| Gastroenteritis
| 1.1%
|
| Vomiting
| 1.1%
|
| Skin
| Rash
| 2.2%
|
| Renal
| Urine Discoloration
| 1.1%
|
Table 7: Incidence (%)* of Adverse Reactions Reported During Clinical Investigations of Pediatric Patients Neonates to 3 Months of Age Treated with Imipenem and Cilastatin for Injection (I.V.)
|
| Body System | Adverse Reactions | Frequency (%) |
| Gastrointestinal
| Diarrhea
| 3%
|
| CNS
| Convulsions
| 5.9%
|
| Cardiovascular
| Tachycardia
| 1.5%
|
| Skin
| Rash
| 1.5%
|
| Body as a Whole
| Oral Candidiasis
| 1.5%
|
| Renal
| Oliguria/Anuria
| 2.2%
|
Adverse Laboratory Changes
The following adverse laboratory changes were reported in studies of 178 pediatric patients 3 months of age: increased AST (SGOT), decreased hemoglobin/hematocrit, increased platelets, increased eosinophils, increased ALT (SGPT), increased urine protein, decreased neutrophils.
The following adverse laboratory changes were reported in studies of 135 patients (neonates to 3 months of age): increased eosinophils, increased AST (SGPT), increased serum creatinine, increased/decreased platelet count, increased/decreased bilirubin, increased ALT (SGPT), increased alkaline phosphatase, increased/decreased hematocrit.
Adverse Laboratory Changes
Adverse laboratory changes reported since the drug was marketed were:
Hematologic: agranulocytosis.
Examination of published literature and spontaneous adverse reactions reports suggested a similar spectrum of adverse reactions in adult and pediatric patients.
Risk Summary
Available data from a small number of postmarketing cases with Imipenem and Cilastatin for Injection (I.V.) use in pregnancy are not sufficient to identify any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes.
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 the RHD (based on body surface area) showed an increase in embryonic loss
(see
Data)
.
The background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The background risk of major birth defects is 2-4% and of miscarriage is 15-20% of clinically recognized pregnancies within the general population.
Data
Animal Data
Reproductive toxicity studies with imipenem and cilastatin (alone or in combination) administered to mice, rats, and rabbits showed no evidence of effects on embryofetal (mice, rats and rabbits) or pre/postnatal (rats) development.
Imipenem was administered intravenously to rats (gestation days (GD) 7 to 17) and rabbits (GD 6 to 18) at doses up to 900 and 60 mg/kg/day, respectively, approximately 2.9 and 0.4 times the RHD (based on body surface area).
Cilastatin was administered subcutaneously to rats (GD 6 to 17) and intravenously to rabbits (GD 6 to 18) at doses up to 1000 and 300 mg/kg/day, respectively, approximately 3.2 and 1.9 times the RHD (based on body surface area).
Imipenem/cilastatin was administered intravenously to mice at doses up to 320 mg/kg/day (GD 6 to 15). In two separate studies, imipenem/cilastatin was administered to rats (GD 6 to 17 and GD 15 to day 21 postpartum) both intravenously at doses up to 80 mg/kg/day and subcutaneously at 320 mg/kg/day. The higher dose is approximately equal to the RHD (based on body surface area).
Imipenem/cilastatin administered intravenously to pregnant cynomolgus monkeys during organogenesis at 100 mg/kg/day, approximately 0.6 times the RHD (based on body surface area), at an infusion rate mimicking human clinical use, was not associated with fetal malformations, but there was an increase in embryonic loss relative to controls. Imipenem/cilastatin administered to pregnant cynomolgus monkeys during organogenesis at 40 mg/kg/day by bolus intravenous injection caused significant maternal toxicity including death and embryofetal loss.
Risk Summary
There are insufficient data on the presence of imipenem/cilastatin in human milk, and no data on the effects on the breastfed child, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Imipenem and Cilastatin for Injection (I.V.) and any potential adverse effects on the breastfed child from Imipenem and Cilastatin for Injection (I.V.) or from the underlying maternal condition.
Distribution
The binding of imipenem to human serum proteins is approximately 20% and that of cilastatin is approximately 40%.
Imipenem has been shown to penetrate into human tissues, including vitreous humor, aqueous humor, lung, peritoneal fluid, CSF, bone, interstitial fluid, skin, and fascia. As there are no adequate and well-controlled studies of imipenem treatment in these additional body sites, the clinical significance of these tissue concentration data is unknown.
After a 1 gram dose of Imipenem and Cilastatin for Injection (I.V.), the following average levels of imipenem were measured (usually at 1 hour post dose except where indicated) in the tissues and fluids listed in
Table 9:
Table 9: Average Levels of Imipenem
Tissue or Fluid
| N
| Imipenem Level mcg/mL or mcg/g
| Range
|
| Vitreous Humor
| 3
| 3.4 (3.5 hours post dose)
| 2.88 to 3.6
|
| Aqueous Humor
| 5
| 2.99 (2 hours post dose)
| 2.4 to 3.9
|
| Lung Tissue
| 8
| 5.6 (median)
| 3.5 to 15.5
|
| Sputum
| 1
| 2.1
| —
|
| Pleural
| 1
| 22
| —
|
| Peritoneal
| 12
| 23.9 S.D.±5.3 (2 hours post dose)
| —
|
| Bile
| 2
| 5.3 (2.25 hours post dose)
| 4.6 to 6
|
| CSF (uninflamed)
| 5
| 1 (4 hours post dose)
| 0.26 to 2
|
| CSF (inflamed)
| 7
| 2.6 (2 hours post dose)
| 0.5 to 5.5
|
| Fallopian Tubes
| 1
| 13.6
| —
|
| Endometrium
| 1
| 11.1
| —
|
| Myometrium
| 1
| 5
| —
|
| Bone
| 10
| 2.6
| 0.4 to 5.4
|
| Interstitial Fluid
| 12
| 16.4
| 10 to 22.6
|
| Skin
| 12
| 4.4
| NA
|
| Fascia
| 12
| 4.4
| NA
|
Metabolism
Imipenem, when administered alone, is metabolized in the kidneys by dehydropeptidase I, resulting in relatively low levels in urine. Cilastatin an inhibitor of this enzyme, effectively prevents renal metabolism of imipenem so that when imipenem and cilastatin sodium are given concomitantly, adequate antibacterial levels of imipenem are achieved in the urine.
Elimination
The plasma half-life of each component is approximately 1 hour. Approximately 70% of the administered imipenem is recovered in the urine within 10 hours after which no further urinary excretion is detectable. Urine concentrations of imipenem in excess of 10 mcg/mL can be maintained for up to 8 hours with Imipenem and Cilastatin for Injection (I.V.) at the 500 mg dose. Approximately 70% of the cilastatin sodium dose is recovered in the urine within 10 hours of administration of Imipenem and Cilastatin for Injection (I.V.). Imipenem and Cilastatin for Injection (I.V.) is hemodialyzable
[see Overdosage (
10)]
.
No accumulation of imipenem/cilastatin in plasma or urine is observed with regimens administered as frequently as every 6 hours in patients with normal renal function.
Specific Populations
Geriatric Patients
In healthy elderly volunteers (65 to 75 years of age with normal renal function for their age), the pharmacokinetics of a single dose of imipenem 500 mg and cilastatin 500 mg administered intravenously over 20 minutes are consistent with those expected in subjects with slight renal impairment for which no dosage alteration is considered necessary. The mean plasma half-lives of imipenem and cilastatin are 91 ± 7 minutes and 69 ± 15 minutes, respectively. Multiple dosing has no effect on the pharmacokinetics of either imipenem or cilastatin, and no accumulation of imipenem/cilastatin is observed.
Pediatric Patients
Doses of 25 mg/kg/dose in patients 3 months to < 3 years of age, and 15 mg/kg/dose in patients 3 to 12 years of age were associated with mean trough plasma concentrations of imipenem of 1.1±0.4 mcg/mL and 0.6±0.2 mcg/mL following multiple 60-minute infusions, respectively; trough urinary concentrations of imipenem were in excess of 10 mcg/mL for both doses. These doses have provided adequate plasma and urine concentrations for the treatment of non-CNS infections.
In a dose-ranging study of smaller premature infants (670 to 1,890 g) in the first week of life, a dose of 20 mg/kg q12h by 15 to 30 minutes infusion was associated with mean peak and trough plasma imipenem concentrations of 43 mcg/mL and 1.7 mcg/mL after multiple doses, respectively. However, moderate accumulation of cilastatin in neonates may occur following multiple doses of Imipenem and Cilastatin for Injection (I.V.). The safety of this accumulation is unknown.
Mechanism of Action
Imipenem and Cilastatin for Injection (I.V.) is a combination of imipenem and cilastatin. The bactericidal activity of imipenem results from the inhibition of cell wall synthesis. Its greatest affinity is for penicillin binding proteins (PBPs) 1A, 1B, 2, 4, 5 and 6 of
Escherichia coli, and 1A, 1B, 2, 4 and 5 of
Pseudomonas aeruginosa. The lethal effect is related to binding to PBP 2 and PBP 1B.
Imipenem has a high degree of stability in the presence of beta-lactamases, both penicillinases and cephalosporinases produced by Gram-negative and Gram-positive bacteria. It is a potent inhibitor of beta-lactamases from certain Gram-negative bacteria which are inherently resistant to most beta-lactam antibacterials, e.g.,
Pseudomonas aeruginosa,
Serratia spp., and
Enterobacter spp.
Resistance
Imipenem is inactive
in vitro against
Enterococcus faecium,
Stenotrophomonas maltophilia and some isolates of
Burkholderia cepacia. Methicillin-resistant staphylococci should be reported as resistant to imipenem.
Interaction with Other Antimicrobials
In vitro tests show imipenem to act synergistically with aminoglycoside antibacterials against some isolates of
Pseudomonas aeruginosa.
Antimicrobial Activity
Imipenem has been shown to be active against most isolates of the following microorganisms, both
in vitro and in clinical infections
[see Indications and Usage (
1)]
.
Aerobic bacteria
Gram-positive bacteria
Enterococcus faecalis
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus agalactiae (Group B streptococci)
Streptococcus pneumoniae Streptococcus pyogenes
Gram-negative bacteria
Acinetobacter spp.
Citrobacter spp.
Enterobacter spp.
Escherichia coli
Gardnerella vaginalis
Haemophilus influenzae
Haemophilus parainfluenzae
Klebsiella spp.
Morganella morganii
Proteus vulgaris
Providencia rettgeri
Pseudomonas aeruginosa
Serratia spp., including
S. marcescens
Anaerobic bacteria
Gram positive bacteria
Bifidobacterium spp.
Clostridium spp.
Eubacterium spp.
Peptococcus spp.
Peptostreptococcus spp.
Propionibacterium spp.
Gram-negative bacteria
Bacteroides spp.
, including B. fragilis
Fusobacterium spp.
The following
in vitro data are available, but their clinical significance is unknown. At least 90 percent of the following bacteria exhibit an
in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for imipenem against isolates of similar genus or organism group. However, the efficacy of imipenem in treating clinical infections due to these bacteria has not been established in adequate and well-controlled clinical trials.
Aerobic bacteria
Gram-positive bacteria
Bacillus spp.
Listeria monocytogenes
Nocardia spp.
Staphylococcus saprophyticus
Group C streptococci
Group G streptococci
Viridans group streptococci
Gram-negative bacteria
Aeromonas hydrophila
Alcaligenes spp.
Capnocytophaga spp.
Haemophilus ducreyi
Neisseria gonorrhoeae
Pasteurella spp.
Providencia stuartii
Anaerobic bacteria
Prevotella bivia
Prevotella disiens
Prevotella melaninogenica Veillonella spp.
Susceptibility Testing
For specific information regarding susceptibility test methods, interpretive criteria, and associated test methods and quality control standards recognized by FDA for this drug, please see: https://www.fda.gov/STIC.
Before Reconstitution:
Imipenem and Cilastatin for Injection, USP (I.V.) sterile powder should be stored at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature].