Doxycycline Pediatric Dose Calculator
Weight-based doxycycline dosing for children — 2.2 mg/kg/dose · every 12 hours · max 100 mg/dose. Enter age and weight for the dose in mg and syrup mL or tablets.
Pediatric dosing
Rickettsial infection (scrub typhus, spotted fevers) — any age
Other infections (≥8 years)
Doxycycline dose chart by age and weight
Rickettsial infection (scrub typhus, spotted fevers) — any age. Weights are WHO/IAP reference medians for age — always dose on the measured weight.
| Age | Weight | Dose (mg) | Suspension 25 mg/5 mL (where available) | Frequency |
|---|---|---|---|---|
| 1 month | 4.3 kg | 9.46 mg | 1.9 mL | Every 12 hours |
| 3 months | 6.1 kg | 13.4 mg | 2.7 mL | Every 12 hours |
| 6 months | 7.6 kg | 16.7 mg | 3.3 mL | Every 12 hours |
| 9 months | 8.6 kg | 18.9 mg | 3.8 mL | Every 12 hours |
| 1 year | 9.3 kg | 20.5 mg | 4.1 mL | Every 12 hours |
| 18 months | 10.6 kg | 23.3 mg | 4.7 mL | Every 12 hours |
| 2 years | 11.8 kg | 26 mg | 5.2 mL | Every 12 hours |
| 3 years | 14.1 kg | 31 mg | 6.2 mL | Every 12 hours |
| 4 years | 16.2 kg | 35.6 mg | 7.1 mL | Every 12 hours |
| 5 years | 17.5 kg | 38.5 mg | 7.7 mL | Every 12 hours |
| 6 years | 19 kg | 41.8 mg | 8.4 mL | Every 12 hours |
| 8 years | 24.4 kg | 53.7 mg | 10.5 mL | Every 12 hours |
| 10 years | 31.1 kg | 68.4 mg | 13.5 mL | Every 12 hours |
| 12 years | 39.4 kg | 86.7 mg | 17.5 mL | Every 12 hours |
Strengths in the calculator
- Suspension 25 mg/5 mL (where available) (Oral)
- Tablet 100 mg (Oral)
- Capsule 100 mg (Oral)
Different strength on your bottle? Use “Different strength on the bottle?” under the result.
Safety
Contraindications and cautions
- Pregnancy (except life-threatening rickettsial disease).
- Longer courses in children under 8 years (dental staining).
Pregnancy and breastfeeding
Legacy FDA category D. Avoid in pregnancy except for life-threatening rickettsial disease.
Short courses are considered acceptable.
Clinical notes
Swallow with a full glass of water and stay upright for 30 minutes (oesophageal ulceration). Avoid taking with milk, antacids, iron or zinc. Photosensitivity.
Adult and adolescent (≥40 kg) dose
100 mg — Every 12 hours (200 mg on day 1 for some indications) (max 100 mg per dose).
Other names and brands
- India: Doxy-1
- USA: Vibramycin
Brand examples only — products and strengths vary by country. Always check the label.
Frequently asked questions
What is the doxycycline dose for children?
Rickettsial infection (scrub typhus, spotted fevers) — any age: 2.2 mg/kg/dose · every 12 hours · max 100 mg/dose. Usual duration: 7 days, and at least 3 days after fever settles. Always use the child's measured weight and check the strength on the bottle.
How many mL of suspension 25 mg/5 mL (where available) for an 11.8 kg child?
For rickettsial infection (scrub typhus, spotted fevers) — any age, an 11.8 kg child (about 2 years) needs 26 mg per dose — 5.2 mL of Suspension 25 mg/5 mL (where available), every 12 hours. Recalculate with the child's actual weight.
From what age can doxycycline be given?
Age range in PediaRx: Rickettsial disease: any age · other uses: ≥8 years. The calculator does not calculate a dose below 1 month. Each indication can have its own age and weight limits, shown with its regimen.
Is doxycycline safe in pregnancy?
Legacy FDA category D. Avoid in pregnancy except for life-threatening rickettsial disease.
Sources and editorial process
- Diagnosis and management of tickborne rickettsial diseases (Biggs et al., MMWR Recomm Rep 2016;65(2)) — U.S. Centers for Disease Control and Prevention
- Red Book: Report of the Committee on Infectious Diseases (tetracyclines) — American Academy of Pediatrics
- BNF for Children — Doxycycline — NICE / BMJ Group / Royal Pharmaceutical Society
Dosing data last updated 2026-09-27. PediaRx is built and maintained by Dr. Shounak Pal, MBBS (Medical Officer, Government of West Bengal, India — founder and developer of PediaRx). Every regimen is encoded with explicit units, maximum doses and age/weight limits and is checked by automated tests before publication. Report an error: hello@pediarx.com.
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Clinical disclaimer: reference tool for qualified health professionals. Verify every dose against current guidance and the product label before prescribing.
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