How the dose is calculated
Like other fluoroquinolones, levofloxacin is generally reserved for infections with no equally effective, safer alternative. Younger children (roughly 6 months–5 years) clear the drug faster and need twice-daily dosing, while older children and adults use a once-daily regimen at the same per-kg dose per administration.
Typical dosing by indication
| Indication | Dose | Frequency | Max |
|---|---|---|---|
| ≥5 years | 10 mg/kg once daily | once daily | 750 mg/day |
| 6 months–5 years | 10 mg/kg per dose, twice daily | every 12h (2×/day) | 500 mg/day |
| Adult (fixed dose, PO/IV) | 500 mg once daily | once daily | 500-750 mg/day* |
*Adults are generally dosed with a fixed 500 mg once daily for most standard indications (community-acquired pneumonia, complicated UTI/pyelonephritis, skin/soft-tissue infection); 750 mg once daily is used for more severe infections (e.g. nosocomial pneumonia, complicated intra-abdominal infection) per indication-specific guidance — oral and IV doses are equivalent because of levofloxacin's near-complete oral bioavailability.
Clinical use
- Fluoroquinolones like levofloxacin are generally reserved in children under 18 for infections where no equally effective, safer alternative exists, because of an animal-model cartilage-toxicity signal — used more often for specific indications (e.g. complicated infection, multidrug-resistant organisms) than as routine first-line therapy.
- Younger children (roughly 6 months to 5 years) clear levofloxacin faster and require twice-daily dosing to maintain adequate levels, while older children and adults achieve the same exposure with once-daily dosing.
- Strong 'respiratory quinolone' activity against Streptococcus pneumoniae and atypical organisms makes it useful for community-acquired pneumonia when specifically indicated.
- Can prolong the QT interval and lower seizure threshold — use caution with relevant comorbidities or interacting medications, and avoid co-administration with calcium/iron/antacids (reduced absorption).
- IV infusion must be given slowly (over at least 60-90 minutes) — rapid administration is associated with hypotension.
- Blood glucose disturbances (both hyperglycaemia and hypoglycaemia) have been reported, particularly in diabetic patients on oral hypoglycaemics or insulin — monitor glucose more closely during treatment.
Frequently asked questions
Why is levofloxacin dosed differently in young children?
Children roughly 6 months to 5 years old clear levofloxacin from their body faster than older children and adults, so they need the same per-kg dose split twice daily to maintain adequate drug levels, whereas older children and adults can use once-daily dosing.
Why is levofloxacin not first-line in children?
Like other fluoroquinolones, it's generally reserved for infections where no equally effective, safer alternative exists, because of an animal-model signal for cartilage toxicity — its use in children is a considered decision, not a routine first choice.
Can levofloxacin be taken with milk or antacids?
It's best avoided — calcium, iron, and antacids reduce levofloxacin absorption significantly, similar to other fluoroquinolones. Separate dosing from these by at least 2 hours.
What is levofloxacin used for?
It's used for specific respiratory tract infections (including some resistant Streptococcus pneumoniae), complicated urinary tract infections, and other infections where its broad Gram-negative and 'respiratory' Gram-positive coverage is specifically needed.
What is the standard adult levofloxacin dose?
500 mg once daily (PO or IV — the two are equivalent) for most standard indications, or 750 mg once daily for more severe infections per the specific indication. This is a fixed adult dose rather than weight-based, unlike the paediatric dosing above.
Why must IV levofloxacin be given slowly?
Rapid IV infusion is associated with hypotension — each dose should be infused over at least 60-90 minutes, not given as a rapid push or short infusion.
Is levofloxacin safe in diabetes?
Use with caution — fluoroquinolones including levofloxacin can disturb blood glucose control in either direction (hyperglycaemia or hypoglycaemia), particularly in patients on oral hypoglycaemic agents or insulin. Monitor glucose more closely during treatment.
References
- Bradley JS, et al. PIDS/IDSA Community-Acquired Pneumonia Guideline. Clin Infect Dis. 2011.
- American Academy of Pediatrics Red Book — Fluoroquinolone use in children.
- British National Formulary for Children (BNFc) — Levofloxacin.