Ceftriaxone
Ceftriaxone sodium
Also known as: Rocephin · ceftriaxonum natricum · Ro-139904 · Ro-13-9904/000
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceBorreliosis | Lyme disease | Borrelia burgdorferi infection (extra-label)
Verified clinician required
- q24h
NA
Governing clinical context (2)
- NOTE: In humans, it is recommended that IV infusions be administered over 30 minutes (60 minutes in neonates) at concentrations between 10 – 40 mg/mL. 9
- The sterile powder for reconstitution should be stored between 20°C to 25°C (68°F-77°F) and protected from light.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Ceftriaxone is a potent, injectable third-generation cephalosporin antibiotic.
- Broad Spectrum: It retains the gram-positive activity of first- and second-generation agents but features significantly expanded gram-negative coverage (e.g., Enterobacteriaceae).
- Clinical Utility: Often reserved for serious infections where less expensive agents are ineffective, or to avoid the nephrotoxicity associated with aminoglycosides.
- Key Advantages: Exhibits excellent penetration into the central nervous system (CNS), making it highly effective for meningitis. Its long half-life and activity against Borrelia burgdorferi also make it a viable option for treating Lyme disease.
Mechanism of action
Like all beta-lactam antibiotics, ceftriaxone is bactericidal.
- Mechanism: It binds to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall.
- Pathway: Binding to PBPs → Inhibition of the third and final stage of bacterial cell wall synthesis → Disruption of peptidoglycan cross-linking → Autolysin-mediated bacterial cell lysis and death.
Safety & warnings
Contraindications
- Prior allergic reaction to cephalosporins
Adverse effects
- Pain on IM injection
- Hypersensitivity reactions (rash)
- Granulocytopenia / thrombocytopenia
- Diarrhea
- Mild azotemia
- Biliary sludging (at very high doses)
- Increased liver enzymes, BUN, and creatinine
Precautions
Important: Give IV injections slowly over at least 30 minutes to minimize adverse reactions.
- Hypersensitivity: Contraindicated in patients with known cephalosporin allergies. Use with caution in penicillin-allergic patients due to potential cross-reactivity.
- Hepatic/Coagulation Issues: Use cautiously in patients with severe hepatic disease or vitamin K synthesis abnormalities, as cephalosporins can rarely affect bleeding times.
- Renal Impairment: Dosage adjustments may be necessary in severe uremia, especially if concomitant hepatic impairment exists.
- Biliary Sludging: High doses may cause biliary sludging (pseudolithiasis), particularly noted in dogs at very high doses (100 mg/kg/day).
Drug interactions
Potential additive nephrotoxicity; in vitro studies show synergistic or additive antibacterial activity.
Concomitant use with calcium-containing solutions has caused fatal calcium-ceftriaxone precipitates in neonates. Do not mix with calcium or administer within 48 hours of ceftriaxone.
Monitoring
- Clinical efficacy
- CBC (with long-term therapy)
- Renal function (BUN, Serum Creatinine, urinalysis)
- Liver enzymes (AST, ALT)
Pharmacokinetics
Half-life
Absorption
Not absorbed after oral administration; must be given parenterally. In dogs, IM and SC bioavailability equals IV. Peak levels occur faster after IM (~30 minutes) than SC (~80 minutes).
Distribution
Widely distributed throughout the body. CSF levels are higher when meninges are inflamed. Crosses the placenta and enters maternal milk in low concentrations.
Metabolism
Not extensively metabolized.
Elimination
Excreted by both renal and non-renal (biliary) mechanisms.
Overdose
Limited information is available regarding acute toxicity. Overdoses should be monitored and treated symptomatically and supportively if required.
Available products
Formulations
- Injection powder for solution
Human-labeled
- Ceftriaxone Injection Powder for Solution: 250 mg, 500 mg, 1 g, 2 g, & 10 g (as base) in vials, single-use duplex containers, and in bulk
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store sterile powder at or below 25°C and protect from light. Reconstituted solutions (100 mg/mL) are stable for 3 days at room temperature and 10 days refrigerated. Solutions of 250 mg/mL are stable for 24 hours at room temperature and 3 days refrigerated. Frozen solutions (10-40 mg/mL) at -20°C are stable for 26 weeks.
Client information
Note: Ceftriaxone is an injectable medication typically administered in a hospital setting by veterinary professionals.
- Injection Site Pain: Your pet may experience some pain or discomfort at the site of an intramuscular (IM) injection.
- Gastrointestinal Upset: Watch for signs of diarrhea or loose stools, which can occur with many antibiotics.
- Allergic Reactions: Contact your veterinarian immediately if you notice signs of an allergic reaction, such as facial swelling, hives, rash, or difficulty breathing.
- Monitoring: If your pet is receiving this medication long-term, your veterinarian may recommend periodic blood tests to monitor liver and kidney function.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.