Baby Safety / Compounds / Isoniazid

Is Isoniazid safe for babies and kids?

Moderate risk for kids

Infants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Isoniazid poses heightened risk.

What is isoniazid?

Also known as: Isonicotinic acid hydrazide, Isonicotinohydrazide, pyridine-4-carbohydrazide, Isoniazide.

CAS number
54-85-3
Molecular formula
C6H7N3O
Molecular weight
137.14 g/mol
SMILES
C1=CN=CC=C1C(=O)NN
PubChem CID
3767

Risk for babies

Moderate risk

Infants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Isoniazid poses heightened risk.

Neonates and infants up to 12 months have incomplete blood-brain barrier development, immature Phase I/II metabolic enzymes (particularly CYP3A4, UGT1A1), and higher gastrointestinal permeability. Equivalent doses produce higher internal concentrations and longer residence times.

What to do: Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

Risk for pregnant and nursing people

Elevated risk

Isoniazid poses pregnancy risk through potential teratogenicity, altered pharmacokinetics (increased blood volume, changed CYP activity), and placental transfer. FDA pregnancy category should be evaluated.

Suspected reproductive toxicant (GHS H361) or suspected endocrine disruptor. Precautionary approach warranted. Animal studies or limited human data suggest developmental toxicity potential.

What to do: Minimize exposure during pregnancy and lactation. Consult healthcare provider regarding specific risks. Consider alternative products with lower hazard profiles.

Regulatory consensus

1 regulatory bodyhas classified Isoniazid.

AgencyYearClassificationNotes
Regulatory Framework—Regulated as pharmaceutical (FDA/EMA); not typically classified under industrial chemical regulations

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where kids encounter isoniazid

  • Consumer Products — various

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Isoniazid:

  • Alternative drug class
    Trade-offs: Direct chemical substitution requires verification that the replacement does not introduce new hazards (regrettable substitution). Conduct full hazard assessment of proposed alternative before adoption.
    Relative cost: 1.2-2×

Frequently asked questions

Is isoniazid safe for kids?

Infants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Isoniazid poses heightened risk.

What products contain isoniazid?

Isoniazid appears in: various (Consumer products).

What should I do if my child is exposed to isoniazid?

Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

See Isoniazid in the baby app

Look up products containing isoniazid, compare to alternatives, and explore the full data record.

Open in baby View raw API data

Sources (1)
  1. PubChem (2026) — database

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →