Home Drug Doses Ceftriaxone
💊 3rd-generation cephalosporin · Broad-spectrum IV/IM antibiotic

Ceftriaxone Dose Calculator

India · Paediatric mg/kg · Neonatal · Adult · Meningitis · Sepsis · Typhoid · CAP · UTI · Monocef · Oframax

Meningitis: 100 mg/kg/day Sepsis: 50–100 mg/kg/day Once daily dosing BNF · IDSA aligned

Ceftriaxone Dose Calculator

Ceftriaxone Dose
Per dose (mg)
Vials required
Daily dose
Duration
💉 Reconstitution guide
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💊 Drug profile
Class3rd-gen cephalosporin
RoutesIV · IM (not oral)
Half-life6–9 hours (adults)
CSF penetrationGood (meningitis)
Renal adj.Not needed (biliary)
Max adult dose4g/day
🏷️ Indian brands
250mg vialMonocef 250 · Oframax 250
500mg vialMonocef 500 · Oframax 500
1g vialMonocef 1g · Oframax 1g · Ceftriax
2g vialMonocef 2g · Oframax 2g
✅ Spectrum coverage

✓ Streptococcus pneumoniae (meningitis, CAP)

✓ Neisseria meningitidis / gonorrhoeae

✓ H. influenzae

✓ Salmonella typhi (typhoid)

✓ E. coli, Klebsiella (UTI, sepsis)

✗ Pseudomonas (use ceftazidime)

✗ MRSA · Enterococcus · Anaerobes

✗ Listeria (neonatal meningitis — add ampicillin)

Ceftriaxone Dosing Reference — Paediatric, Neonatal & Adult

IndicationPaediatric doseAdult doseFrequencyDuration
Bacterial meningitis100 mg/kg/day (max 4g)2g every 12 hoursBD (q12h) for meningitis7–10d (pneumococcal); 7d (meningococcal)
Sepsis / severe infection50–80 mg/kg/day (max 4g)2g once dailyOD or BD7–14 days (guided by clinical response)
Typhoid — severe / IV75 mg/kg/day (max 2.5g)2–3g once dailyOnce daily10–14 days
Community pneumonia (CAP)50 mg/kg/day (max 2g)1–2g once dailyOnce daily5–7 days
Complicated UTI50 mg/kg/day (max 2g)1–2g once dailyOnce daily10–14 days
Gonorrhoea (single dose)125–250 mg IM (single)500mg IM (single) — WHO 2016Single doseSingle dose
Surgical prophylaxis50 mg/kg (max 2g)1–2gSingle dose 30–60 min pre-incisionSingle dose
Neonatal sepsis (term)50 mg/kg ODOnce daily10–14 days
Neonatal meningitis50 mg/kg BDEvery 12 hours21 days

Ceftriaxone — Clinical Guide India

Ceftriaxone is a third-generation cephalosporin and one of the most widely used IV/IM antibiotics in Indian hospitals. It provides broad Gram-negative and Gram-positive coverage with excellent tissue penetration, including the central nervous system — making it first-line for bacterial meningitis in India. Its long half-life (6–9 hours) allows once-daily dosing for most indications, reducing nursing workload and improving compliance. Available as Monocef and Oframax in 250mg, 500mg, 1g, and 2g vials.

Meningitis — the highest-dose indication

Bacterial meningitis requires the highest ceftriaxone doses because adequate CSF drug levels are essential and the blood-brain barrier limits CNS penetration. Paediatric dose: 100 mg/kg/day — given as 50 mg/kg every 12 hours. Adult dose: 2g every 12 hours. Always give dexamethasone 0.15 mg/kg IV before or with the first antibiotic dose in suspected bacterial meningitis — this significantly reduces hearing loss (particularly in H. influenzae meningitis) and meningeal inflammation. If Listeria monocytogenes is possible (neonates, immunocompromised, elderly), add ampicillin — ceftriaxone does not cover Listeria.

Critical neonatal caution — calcium interaction

Ceftriaxone is contraindicated in neonates receiving calcium-containing IV fluids simultaneously — including total parenteral nutrition (TPN) and Ringer's lactate. Ceftriaxone-calcium precipitates form in the lungs and kidneys and have caused neonatal deaths. Use cefotaxime instead in neonates requiring concurrent calcium administration. This is a critical patient safety issue — the interaction is not relevant in older children and adults at the doses used clinically.

IM reconstitution — reducing injection pain

For IM ceftriaxone, the vial should be reconstituted with 1% lignocaine (lidocaine) solution (not water) to significantly reduce injection pain. For a 1g vial: add 3.5ml of 1% lignocaine. For a 500mg vial: add 2ml of 1% lignocaine. Inject deep IM into the upper outer gluteal quadrant. Never exceed 1g per injection site — if 2g is needed IM, give 1g at each gluteal site. Never reconstitute with lignocaine for IV use.

Typhoid — when to use ceftriaxone vs azithromycin

For uncomplicated typhoid in ambulatory patients, azithromycin oral remains the first-line agent in India (see Azithromycin page). Ceftriaxone IV is used when: the patient cannot take oral medications (vomiting), severe typhoid with complications (intestinal perforation, hepatitis, encephalopathy), failed oral azithromycin, or when confirmed ceftriaxone-sensitive isolate on culture. Duration: 10–14 days IV for severe cases.

Frequently Asked Questions

How to reconstitute ceftriaxone 1g for IV infusion?+
For IV infusion: reconstitute ceftriaxone 1g vial with 10ml of sterile water for injection to make a 100mg/ml solution. Then dilute further in 50–100ml of normal saline (0.9% NaCl) or 5% dextrose. Infuse over 30 minutes. Do NOT dilute in calcium-containing solutions (Ringer's lactate, Hartmann's) — precipitate forms. For IM use: reconstitute with 3.5ml of 1% lignocaine (not water) to reduce pain.
Does ceftriaxone need dose adjustment for kidney disease?+
No. Ceftriaxone is eliminated 40–65% by biliary/faecal route and 35–60% by renal route. Unlike most cephalosporins, it does not require dose adjustment for renal impairment — including patients on dialysis. This makes it particularly valuable in patients with CKD or AKI where other antibiotics require complex dose adjustments. In severe hepatorenal failure (both liver and kidney), the maximum dose should be limited to 2g/day.
Can ceftriaxone be given as a once-daily dose for meningitis?+
For meningitis, 12-hourly (BD) dosing is preferred over once-daily dosing to maintain more consistent CSF drug levels. Some studies show once-daily dosing at 100 mg/kg is adequate for pneumococcal meningitis, but BNF, BNF for Children, and most Indian guidelines recommend BD dosing for meningitis to ensure adequate coverage throughout the full 24-hour period.
⚠️Never mix ceftriaxone with calcium-containing IV fluids. Neonates: use cefotaxime if concurrent calcium/TPN is required. Verify doses against BNF, local antibiotic policy, and sensitivity results.

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