Corticosteroid Eye Drops
Moderate
Database
Steroids worsen fungal keratitis
Avoid concurrent ocular corticosteroids
Source: Kimi deep-research + Cla
Drug reference
Natamycin
Polyene antifungal (ophthalmic) · Antifungal
Also known as Pimaricin
START
5% suspension 1 drop q1–2h ×3–4 days, then 6–8×/day; total ~2–3 weeks
TYPICAL MAX
Hourly initial dosing then taper (no systemic ceiling)
STOP IF
Lack of clinical improvement after 7–10 days (reassess; consider deep infection/alternative)
WATCH
Clinical/microscopic response, corneal scraping if no improvement, consider systemic antifungal for deep keratitis
CDSCO approvedSchedule HATC S01AA10
KDIGO 2024 + manufacturer label
- ONSET
- 2h · surface antifungal action
- PEAK
- 2h · local
- t½
- 1h · surface (illustrative; not systemic)
- DURATION
- 2h · frequent dosing interval
EXCRETION
Topical; negligible systemic absorption
route + CYP
INTERACTIONS
—
none in our sources
PREGNANCY
Topical — minimal systemic exposure; use if needed for sight-threatening infection
FDA category + note
Available in India
28 branded formulations. Look up specific brands in the Drugs workspace.
Mechanism
Binds fungal membrane ergosterol, disrupting membrane integrity and transport → fungistatic/fungicidal; topical ophthalmic, negligible systemic/ocular penetration (acts on corneal surface).
Indications
Fungal keratitis, blepharitis and conjunctivitis (esp. filamentous fungi e.g. Fusarium, Aspergillus)
Dosing
- Adult
- 5% ophthalmic suspension: 1 drop every 1–2 h for 3–4 days, then 1 drop 6–8×/day; continue 14–21 days, taper by response.
- Pediatric
- As adult (specialist ophthalmology).
- Renal adjustment
- Not applicable (topical, negligible absorption).
- Hepatic adjustment
- Not applicable.
- Geriatric
- No specific adjustment.
- Max dose
- Hourly initial dosing then taper (no systemic ceiling)
Pharmacokinetics
Onset
Antifungal at corneal surface over days
Peak effect
Local
Duration
Frequent topical dosing
Half-life
Not systemically relevant (poor penetration/absorption)
Bioavailability
Negligible systemic; remains on corneal surface
Protein binding
Not relevant
Metabolism
Not relevant (topical)
Excretion
Not relevant (topical)
Contraindications
- Hypersensitivity to natamycin
Side effects
Common
Eye irritation/stingingBlurred visionConjunctival chemosis/hyperaemiaAdherent white deposits on cornea
Serious
- Allergic/hypersensitivity reaction (rare)
- Treatment failure for deep stromal/endophthalmitis (poor penetration) — needs systemic therapy
Pregnancy & lactation
Pregnancy
Topical — minimal systemic exposure; use if needed for sight-threatening infection
Lactation
Topical ophthalmic — negligible systemic; considered low risk
Drug interactions
Contact Lenses
Mild
Database
Lenses impede therapy/harbour fungus
Do not wear lenses during treatment
Source: Kimi deep-research + Cla
None Significant Systemic
Mild
Database
Negligible absorption → minimal systemic interactions
No systemic action
Source: Kimi deep-research + Cla
Other Ophthalmic Preparations
Mild
Database
Dilution/washout if instilled together
Separate instillation by ≥5–10 min
Source: Kimi deep-research + Cla
Systemic Antifungals
Mild
Database
Combined for deep keratitis (beneficial)
Use systemic agent for stromal/deep involvement
Source: Kimi deep-research + Cla
Ask House about Natamycin
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: Goodman & Gilman 14e, Katzung·Verified: 2026-05-19 · House clinical team·Cockpit curated: 2026-05-19