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Primaxin IV Dosage

Generic name: IMIPENEM 250mg in 100mL, CILASTATIN SODIUM 250mg in 100mL
Dosage form: injection, powder, for solution
Drug class: Carbapenems

Medically reviewed by Drugs.com. Last updated on Dec 1, 2023.

Dosage in Adults

For Intravenous Injection Only

  • The dosage of PRIMAXIN in adult patients should be based on suspected or confirmed pathogen susceptibility as shown in Table 1 below. The dosage recommendations for PRIMAXIN represent the quantity of imipenem to be administered. An equivalent amount of cilastatin is also present in the solution.
  • These doses should be used for patients with creatinine clearance of greater than or equal to 90 mL/min. A reduction in dose must be made for patients with creatinine clearance less than 90 mL/min as shown in Table 3 [see Dosage and Administration (2.3)].
  • Recommend that the maximum total daily dosage not exceed 4 g/day.
  • Administer 500 mg by intravenous infusion over 20 to 30 minutes.
  • Administer 1000 mg by intravenous infusion over 40 to 60 minutes.
  • In patients who develop nausea during the infusion, the rate of infusion may be slowed.
Table 1: Dosage of PRIMAXIN in Adult Patients with Creatinine Clearance Greater than or Equal to 90 mL/min
Suspected or Proven Pathogen Susceptibility Dosage of PRIMAXIN
If the infection is suspected or proven to be due to a susceptible bacterial species 500 mg every 6 hours
OR
1000 mg every 8 hours
If the infection is suspected or proven to be due to bacterial species with intermediate susceptibility [see Microbiology (12.4)] 1000 mg every 6 hours

Dosage in Pediatric Patients

PRIMAXIN is not recommended in pediatric patients with CNS infections because of the risk of seizures [see Use in Specific Populations (8.4)].

PRIMAXIN is not recommended in pediatric patients <30 kg with renal impairment, as no data are available [see Use in Specific Populations (8.4)].

Based on studies in adults, the maximum total daily dose in pediatric patients should not exceed 4 g/day [see Dosage and Administration (2.1)].

The recommended dosage for pediatric patients with non-CNS infections is shown in Table 2 below:

Table 2: Recommended PRIMAXIN Dosage in Pediatric Patients for Non-CNS Infections
Age Dose (mg/kg) *,† Frequency (hours)
*
Doses less than or equal to 500 mg should be given by intravenous infusion over 20 to 30 minutes
†
Doses greater than 500 mg should be given by intravenous infusion over 40 to 60 minutes Recommend that the maximum total daily dosage not exceed 4g/day
Greater than or equal to 3 Months of Age
15-25 mg/kg Every 6 hours
Less than or equal to 3 months of age (Greater than or equal to 1,500 g body weight)
4 weeks to 3 months of age 25 mg/kg Every 6 hours
1 to 4 weeks of age 25 mg/kg Every 8 hours
Less than 1 week of age 25 mg/kg Every 12 hours

Dosage in Adult Patients with Renal Impairment

Patients with creatinine clearance less than 90 mL/min require dosage reduction of PRIMAXIN as indicated in Table 3. The serum creatinine should represent a steady state of renal function. Use the Cockcroft-Gault method described below to calculate the creatinine clearance:

Males: (weight in kg) × (140-age in years)
(72) × serum creatinine (mg/100 mL)
Females: (0.85) × (value calculated for males)
Table 3: Dosage of PRIMAXIN for Adult Patients in Various Renal Function Groups Based on Estimated Creatinine Clearance (CLcr)
Creatinine clearance (mL/min)
Greater than or equal to 90 Less than 90 to greater than or equal to 60 Less than 60 to greater than or equal to 30 Less than 30 to greater than or equal to 15
*
Administer doses less than or equal to 500 mg by intravenous infusion over 20 to 30 minutes. Discard unused portion of the infusion solution.
†
Administer doses greater than 500 mg by intravenous infusion over 40 to 60 minutes. In patients who develop nausea during the infusion, the rate of infusion may be slowed.
Dosage of PRIMAXIN*,†
If the infection is suspected or proven to be due to a susceptible bacterial species:		 500 mg every 6 hours 400 mg every 6 hours 300 mg every 6 hours 200 mg every 6 hours
OR
1000 mg every 8 hours 500 mg every 6 hours 500 mg every 8 hours 500 mg every 12 hours
Dosage of PRIMAXIN*,†
If the infection is suspected or proven to be due to bacterial species with intermediate susceptibility [see Microbiology (12.4)]:		 1000 mg every 6 hours 750 mg every 8 hours 500 mg every 6 hours 500 mg every 12 hours

In patients with creatinine clearances of less than 30 to greater than or equal to 15 mL/min, there may be an increased risk of seizures [see Warnings and Precautions (5.2) and Use in Specific Populations (8.6)]. Patients with creatinine clearance less than 15 mL/min should not receive PRIMAXIN unless hemodialysis is instituted within 48 hours. There is inadequate information to recommend usage of PRIMAXIN for patients undergoing peritoneal dialysis.

Dosage in Hemodialysis Patients

When treating patients with creatinine clearances of less than 15 mL/min who are undergoing hemodialysis, use the dosage recommendations for patients with creatinine clearances of less than 30 to greater than or equal to 15 mL/min in Table 3 above [see Dosage and Administration (2.3)]. Both imipenem and cilastatin are cleared from the circulation during hemodialysis. The patient should receive PRIMAXIN after hemodialysis and at intervals timed from the end of that hemodialysis session. Dialysis patients, especially those with background CNS disease, should be carefully monitored; for patients on hemodialysis, PRIMAXIN is recommended only when the benefit outweighs the potential risk of seizures [see Warnings and Precautions (5.2)].

Reconstitution and Preparation of PRIMAXIN Solution for Intravenous Administration

PRIMAXIN Vials

  • Do not use diluents containing benzyl alcohol to reconstitute PRIMAXIN for administration to neonates because it has been associated with toxicity in neonates. While toxicity has not been demonstrated in pediatric patients greater than three months of age, small pediatric patients in this age range may also be at risk for benzyl alcohol toxicity.
  • Contents of the vials must be reconstituted by adding approximately 10 mL of the appropriate diluent to the vial. List of appropriate diluents are as follows:
    • 0.9% Sodium Chloride Injection
    • 5% Dextrose Injection
    • 5% Dextrose and 0.9% Sodium Chloride Injection
    • 5% Dextrose Injection with 0.225% or 0.45% saline solution
  • Reconstituted Solutions of PRIMAXIN range from colorless to yellow. Variations of color within this range do not affect the potency of the product.
  • The reconstituted suspension must not be administered by direct Intravenous Infusion
  • After reconstitution, shake vial well and transfer the resulting suspension to 100 mL of an appropriate infusion solution before administering by intravenous infusion.
  • Repeat transfer of the resulting suspension with an additional 10 mL of infusion solution to ensure complete transfer of vial contents to the infusion solution. Agitate the resulting mixture until clear.
  • Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
  • Discard unused portion of the infusion solution where applicable.

Storage of Reconstituted Solutions

Vials (After Reconstitution)

  • PRIMAXIN, 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 PRIMAXIN.

Incompatibility and Compatibility of PRIMAXIN with other Antibacterial Drugs

  • Do not mix PRIMAXIN with, or physically add to, other antibacterial drugs.
  • PRIMAXIN may be administered concomitantly with other antibacterial drugs, such as aminoglycosides.

Further information

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