Can Ceftriaxone (Ceftriaxone) be administered intramuscularly (IM)?

Can Ceftriaxone Be Given Intramuscularly?

Yes, ceftriaxone can be administered intramuscularly and is FDA-approved for IM administration across all age groups, with complete absorption and pharmacokinetics comparable to IV administration. 1

FDA-Approved Routes of Administration

• The FDA label explicitly states that "Ceftriaxone for Injection may be administered intravenously or intramuscularly" for all approved indications 1
• Ceftriaxone is completely absorbed following IM administration, with mean maximum plasma concentrations occurring between 2 and 3 hours post-dose 1
• IM administration achieves plasma concentrations equal to IV administration by 2.5 hours after dosing 2

Standard IM Dosing by Indication

Adults

• Uncomplicated gonococcal infections: 250 mg IM as a single dose 1
• Disseminated gonococcal infection: 1 gram IM every 24 hours 3
• Most serious infections: 1-2 grams IM once daily, with total daily dose not exceeding 4 grams 1
• Surgical prophylaxis: 1 gram IM (though IV is preferred for timing) 1

Pediatric Patients

• Acute bacterial otitis media: Single IM dose of 50 mg/kg (not to exceed 1 gram) 1
• Gonococcal infections in children <45 kg: 125 mg IM single dose for uncomplicated infections 3
• Bacteremia or arthritis: 50 mg/kg IM daily for 7 days (maximum 1 gram) 1
• Serious infections: 50-75 mg/kg IM once daily or divided twice daily 1

Reconstitution for IM Administration

The FDA provides specific reconstitution instructions to achieve appropriate concentrations for IM injection: 1

• For 500 mg vial: Add 1.8 mL diluent for 250 mg/mL concentration, or 1.0 mL for 350 mg/mL concentration
• For 1 gram vial: Add 3.6 mL diluent for 250 mg/mL concentration, or 2.1 mL for 350 mg/mL concentration
• For 2 gram vial: Add 7.2 mL diluent for 250 mg/mL concentration, or 4.2 mL for 350 mg/mL concentration

Administration Technique

• Inject well within the body of a relatively large muscle 1
• Aspiration helps avoid unintentional injection into a blood vessel 1
• IM injection of ceftriaxone is painful and patients should be counseled accordingly 3

Pharmacokinetic Equivalence of IM vs IV Routes

• Mean peak plasma concentration after 1 gram IM is 81 mcg/mL compared to 168 mcg/mL after IV infusion, but concentrations equalize by 2.5 hours 2
• Plasma half-life is essentially identical: 8.3 hours for IM vs 7.6 hours for IV 2
• Urinary recovery within 24 hours is 33-34% for IM vs 40% for IV, demonstrating comparable bioavailability 2
• Plasma concentrations exceed MICs of most susceptible organisms for 24 hours regardless of route 2

Clinical Evidence Supporting IM Use

• A comparative study demonstrated that serum and pleural fluid concentrations following IM administration were well above MIC90 of most common respiratory pathogens, with pharmacokinetics very similar to IV route 4
• IM administration is particularly useful for domiciliary/outpatient parenteral therapy with significant cost-saving potential 4
• Single IM dose of ceftriaxone has been shown highly effective for gonorrhea due to both non-penicillinase-producing and penicillinase-producing strains of Neisseria gonorrhoeae 5

Critical Contraindications for IM Use

• No calcium-containing diluents (such as Ringer's solution or Hartmann's solution) should be used for reconstitution, as particulate formation can result 1
• Hyperbilirubinemic neonates should not receive ceftriaxone IM 1
• Premature neonates are contraindicated from receiving ceftriaxone by any route 1

Practical Advantages of IM Administration

• Once-daily dosing is feasible for most infections due to the long half-life (5.8-8.7 hours) 6
• Eliminates need for IV access in outpatient settings 4
• Particularly advantageous for single-dose therapy (gonorrhea, otitis media) where IV access would be impractical 1, 5
• Multiple dosing at 12- or 24-hour intervals results in only 15-36% accumulation with no change in elimination half-life 6

Common Pitfalls to Avoid

• Do not use IM route for meningitis in neonates—IV administration over 60 minutes is required to reduce risk of bilirubin encephalopathy 1
• Do not assume IM administration is less painful than IV—counsel patients that IM injection causes significant discomfort 3
• Do not exceed 2 grams per injection site—if higher doses are needed, divide between multiple sites or use IV route 1
• Ensure proper reconstitution concentration (250-350 mg/mL) to avoid injection of excessive volumes 1