Ceftriaxone IM for Urinary Tract Infection
Recommended Dose and Duration
For uncomplicated pyelonephritis or complicated UTI requiring parenteral therapy, administer ceftriaxone 1-2 grams IM once daily, with treatment duration of 7-14 days depending on clinical response. 1, 2
Specific Dosing Algorithm
- Standard dose: 1 gram IM once daily is effective for most complicated UTIs 1, 3
- Severe infections: 2 grams IM once daily for hospitalized patients or those with systemic symptoms 1, 2
- Maximum daily dose: Do not exceed 4 grams per day 2
Treatment Duration Decision Tree
- Patient becomes afebrile within 48 hours
- Hemodynamically stable
- Prompt symptom resolution
- No evidence of prostatitis
- Delayed clinical response (fever persisting >72 hours)
- Male patients where prostatitis cannot be excluded
- Presence of diabetes, immunosuppression, or urologic abnormalities
- Catheter-associated UTI with long-term catheter
Administration Technique
Reconstitute ceftriaxone powder with 1.8 mL diluent for 500 mg vial or 3.6 mL for 1 gram vial to achieve 250 mg/mL concentration. 2 Inject deeply into a large muscle mass with aspiration to avoid intravascular injection. 2
Transition to Oral Therapy
Switch to oral step-down therapy once the patient is afebrile for 48 hours and clinically stable. 1, 4
Preferred oral options (in order):
- Ciprofloxacin 500-750 mg twice daily for 7 days - if organism susceptible and local fluoroquinolone resistance <10% 1, 4
- Levofloxacin 750 mg once daily for 5 days - alternative fluoroquinolone option 1, 4
- Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 14 days - if fluoroquinolone-resistant but susceptible to TMP-SMX 1, 4
- Cefpodoxime 200 mg twice daily for 10 days - acceptable but inferior efficacy to fluoroquinolones 1, 4
Critical Management Steps
Always obtain urine culture before initiating antibiotics to guide targeted therapy, as complicated UTIs have broader microbial spectrum and increased antimicrobial resistance. 1
Replace indwelling catheters that have been in place ≥2 weeks at treatment onset, as this hastens symptom resolution and reduces recurrence risk. 1
Reassess at 72 hours if no clinical improvement with defervescence; extended treatment and urologic evaluation may be needed for delayed response. 1
Important Caveats
When NOT to use ceftriaxone:
- Suspected carbapenem-resistant Enterobacterales (CRE): Use ceftazidime/avibactam, meropenem/vaborbactam, or carbapenems instead 1
- Known ESBL-producing organisms: Consider carbapenems as first-line 1
- Multidrug-resistant Pseudomonas: Use ceftolozane/tazobactam or ceftazidime/avibactam 1
Limitations of ceftriaxone:
Ceftriaxone exhibits significant biliary excretion, and in patients with severe renal dysfunction, only minimal urinary concentrations may be present. 5 However, the FDA label confirms no dosage adjustment is necessary for renal or hepatic impairment in standard dosing. 2
Clinical Efficacy Evidence
The single most recent high-quality evidence demonstrates ceftriaxone 1 gram once daily achieved 85-91% clinical efficacy in complicated UTIs with 62.8-86% bacteriologic eradication rates. 6, 7 Ceftriaxone showed superior bacteriologic cure compared to cefazolin three times daily, with similar clinical efficacy but greater convenience. 3, 8