Injectable (Parenteral) Treatment of Typhoid Fever

Injectable antibiotics are reserved for severe, complicated typhoid fever (high fever with toxemia, GI bleeding, intestinal perforation, encephalopathy, shock) or when the patient cannot tolerate oral therapy, and in areas with multidrug-resistant (MDR) or fluoroquinolone-resistant Salmonella Typhi.

First-line injectable options

1. Ceftriaxone (third-generation cephalosporin) - drug of choice for severe/resistant cases

Adults: 2 g IV once daily (or 1 g IV every 12 hours)
Children: 60-75 mg/kg/day IV once daily
Duration: 10-14 days (severe illness) or step down to oral therapy once afebrile and clinically improving
Preferred where extensively drug-resistant (XDR) strains circulate, since it retains activity when fluoroquinolones and older agents fail - Harrison's Principles of Internal Medicine, 22E

2. Cefotaxime

Alternative third-generation cephalosporin used in severe or complicated cases, especially in children - Tintinalli's Emergency Medicine

3. Ciprofloxacin (IV)

Used when the organism is fluoroquinolone-susceptible; can be given IV in severely ill or vomiting patients, then switched to oral
Fluoroquinolone resistance is increasing, particularly in strains from South and Southeast Asia, so local susceptibility should guide use - Tintinalli's Emergency Medicine

4. Azithromycin

Mainly oral, but relevant to mention because it has shown lower relapse rates than fluoroquinolones or ceftriaxone in some studies and is a key alternative in areas of high fluoroquinolone/cephalosporin resistance - Yamada's Textbook of Gastroenterology

Older/alternative injectable agents (used less now, but still described in resistance-based regimens)

From Park's Textbook of Preventive and Social Medicine (Table: Treatment of uncomplicated typhoid fever, susceptibility-based regimens):

Chloramphenicol - 50-75 mg/kg/day, 14-21 days (multidrug-resistant strains often no longer respond)
Ampicillin/Amoxicillin - 75-100 mg/kg/day, 14 days
TMP-SMX - 8-40 mg/kg/day, 14 days

These are now largely superseded by cephalosporins/fluoroquinolones/azithromycin due to widespread MDR S. Typhi.

Adjunct therapy in severe toxic illness

For patients who are severely ill and profoundly toxic (e.g., with delirium, obtundation, shock), IV/IM hydrocortisone 100 mg daily for 3-4 days (or IV dexamethasone in some protocols) is added as adjunctive therapy alongside antibiotics - Park's Textbook of Preventive and Social Medicine.

Resistance context (important for drug choice)

H58 clone MDR strains and an emerging extensively drug-resistant (XDR) S. Typhi clone (with plasmid-mediated ESBL resistance) are now the dominant cause of typhoid in Pakistan and have spread internationally via air travel - Harrison's Principles of Internal Medicine, 22E
Azithromycin resistance has also emerged in some regions, so empiric choice should factor in local/travel-related resistance patterns.

Recent evidence check

A 2024 systematic review of RCTs (PMID: 39623850) compared oral azithromycin against ceftriaxone, chloramphenicol, and fluoroquinolones for typhoid across age groups - findings are broadly consistent with the textbook guidance above (azithromycin as an effective alternative, especially where resistance to other agents is a concern). A 2025 Cochrane review (PMID: 40326553) focused on typhoid conjugate vaccines for prevention rather than treatment, and a 2023 eLife meta-analysis of ~13,000 S. Typhi genomes (PMID: 37697804) confirms the widespread ciprofloxacin resistance driving the shift toward ceftriaxone/azithromycin as first-line therapy. None of these contradict the textbook-based recommendations above; they reinforce them.

Bottom line: for injectable therapy, IV ceftriaxone (or cefotaxime) is the standard first choice for severe or drug-resistant typhoid fever, with IV ciprofloxacin as an option only where fluoroquinolone susceptibility is confirmed, and hydrocortisone as an adjunct in toxic/shock states. Actual drug selection should always be guided by local antimicrobial susceptibility data given the rise of MDR and XDR S. Typhi.

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