Ertapenem is available as a lyophilized powder in single-dose vials containing ertapenem 1 g (equivalent to 1.046 g of ertapenem sodium) with sodium bicarbonate 175 mg and sodium hydroxide to adjust the pH.2973 For intravenous administration, reconstitute the contents of a 1-g vial with 10 mL of sterile water for injection, bacteriostatic water for injection, or sodium chloride 0.9% and shake well,2973 yielding a concentration of 100 mg/mL.2975 For adult patients, immediately transfer the appropriate dose of the reconstituted solution to 50 mL of sodium chloride 0.9%.2973 For pediatric patients, transfer the appropriate dose of reconstituted solution to a volume of sodium chloride 0.9% that is sufficient to yield a final concentration of 20 mg/mL or less.2973
For intramuscular injection, reconstitute the contents of a 1-g vial with 3.2 mL of lidocaine hydrochloride 1% (without epinephrine) and shake well,2973 yielding a final volume of approximately 3.6 mL and a concentration of approximately 280 mg/mL.2975 Upon dissolution, administer within 1 hour.2973 Do not administer the reconstituted intramuscular injection intravenously.2973
pH
7.5.2973
Sodium Content
Each 1-g vial contains approximately 137 mg or 6 mEq of sodium.2973
Trade Name(s)
Invanz
Ertapenem sodium diluted in sodium chloride 0.9% may be administered by intravenous infusion over 30 minutes.2973 Ertapenem sodium prepared with lidocaine hydrochloride 1% for intramuscular administration is administered by deep intramuscular injection into a large muscle mass (e.g., gluteal muscle, lateral part of the thigh).2973
Ertapenem sodium is a white to off-white powder that forms a colorless to pale yellow solution upon reconstitution and dilution.2973 Intact vials should be stored at a temperature not exceeding 25°C.2973 Reconstituted solutions for intravenous administration should be diluted immediately in sodium chloride 0.9%,2973 but has been noted to remain stable in the vial for 2 hours at 25°C or 6 hours at 5°C when reconstituted with sterile water for injection, sodium chloride 0.9%, bacteriostatic water with benzyl alcohol 0.9%, or Ringer’s injection, lactated.2975
Reconstituted solutions of ertapenem sodium (Merck, 100 mg/mL of ertapenem, reconstituted with sodium chloride 0.9%) in the original glass vials or transferred to polypropylene syringes was found to be stable for 2 days at 4°C, or less than 1 day at 23°C.4139 Using data from the study to determine the degradation rate, the authors calculated the time to 90% of initial drug concentration to be approximately 2.3 days at 4°C or 5.5 hr at room temperature.4139 The authors concluded that ertapenem solutions reconstituted with sodium chloride 0.9% in the original glass vials or polypropylene syringes will retain over 90.5% of the initial concentration when stored up to 48 hours at 4°C followed by 1 additional hour at 23°C.4139
The manufacturer recommends that solutions of ertapenem not be frozen.2973
Dextrose-containing solutions should not be used to dilute ertapenem2973 as an unacceptable loss due to degradation has been observed with their use; however, limited contact over a short period of time (e.g., ertapenem run as a piggyback into the same line as dextrose) should not adversely affect ertapenem stability.2975
Diluted solutions for infusion may be stored and used within 6 hours at room temperature or may be stored for 24 hours under refrigeration and used within 4 hours after removal from refrigeration.2973
Reconstituted solutions prepared for intramuscular administration should be used within 1 hour.2973
Freezing Solutions
The manufacturer recommends that solutions of ertapenem not be frozen due to degradation of the drug.2973; 2975
Ertapenem (Merck) 100 mg/mL in sodium chloride 0.9% in polypropylene syringes was frozen at -20°C for 14 or 28 days immediately after preparation, followed by thawing at room temperature for 1 hour.2974 Upon thawing for 1 hour, the solution frozen for 28 days was found to have undergone about 5% loss.2974 The solution frozen for 14 days was found to have undergone about 7% loss after 5 hours at room temperature (including the 1 hour of thawing time).2974
Syringes
Ertapenem (Merck) 100 mg/mL in sodium chloride 0.9% was packaged as 10 mL in 20-mL polypropylene syringes (Monoject).2974 The drug was found to be stable for approximately 30 minutes at room temperature or 24 hours under refrigeration followed by up to 4 hours at room temperature after removal from refrigeration.2974
In another study, reconstituted ertapenem sodium (Merck, 100 mg/mL of ertapenem, reconstituted with sodium chloride 0.9%) stored in 10-mL polypropylene syringes was found to be stable for 2 days at 4°C, or less than 1 day at 23°C.4139 The calculated time to 90% of initial drug concentration was approximately 2.3 days at 4°C or 5.5 hr at room temperature.4139
Elastomeric Reservoir Pumps
Ertapenem sodium (Merck) was reconstituted with sterile water for injection and diluted in sodium chloride 0.9% to a concentration of 10 mg/mL of ertapenem in Homepump Eclipse elastomeric pumps (100-mL capacity, 100-mL/hr flow rate) and stored at 4 to 7°C for 7 days.2723 Although physical compatibility was not evaluated, HPLC analysis indicated all solutions retained at least 90% of drug concentration in 72 hours.2723
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