Drug information of Natamycin


Drug group:

Amphoteric macrolide antifungal antibiotic from Streptomyces natalensis or S. chattanoogensis. It is used for a variety of fungal infections, mainly topically.

Mechanism of effect

LIke other polyene antibiotics, Natamycin inhibits fungal growth by binding to sterols. Specifically, Natamycin binds to ergosterol in the plasma membrane, preventing ergosterol-dependent fusion of vacuoles, as well as membrane fusion and fission. This differs from the mechanism of most other polyene antibiotics, which tend to work by altering fungal membrane permeability instead.


Topical administration appears to produce effective concentrations of natamycin within the corneal stroma but not in intraocular fluid.


  • Absorption: Systemic absorption should not be expected following topical administration
  • Metabolism: N/A
  • Excretion: N/A

Drug indications




Fungal Keratitis

1 gtt in conjunctival sac q1-2hr

May decrease to 1 gtt 6-8 times/day after 3-4 days

Continue for 14-21 days until infection eradicated

Fungal Blepharitis/Conjunctivitis

1 gtt in conjunctival sac 4-6 times/day


Safety & efficacy not established

Drug contraindications


Side effects

eye itching


For keratitis, consider alternative tx if no improvement in 7-10 d

Points of recommendation

Follow all directions on your prescription label. Do not use natamycin ophthalmic in larger or smaller amounts or for longer than recommended.

Wash your hands before using the eye drops.

Shake this medicine well just before each use.

To apply the eye drops:

  • Tilt your head back slightly and pull down your lower eyelid to create a small pocket. Hold the dropper above the eye with the tip down. Look up and away from the dropper and squeeze out a drop.
  • Close your eyes for 2 or 3 minutes with your head tipped down, without blinking or squinting. Gently press your finger to the inside corner of the eye for about 1 minute, to keep the liquid from draining into your tear duct.
  • Wait at least 10 minutes before using any other eye drops your doctor has prescribed.

Do not touch the tip of the eye dropper or place it directly on your eye. A contaminated dropper can infect your eye, which could lead to serious vision problems.

Do not use the eye drops if the liquid has changed colors or has particles in it. Call your pharmacist for new medicine.

Store at room temperature away from moisture, heat, and light. Do not freeze. Keep the bottle tightly closed when not in use.

Use this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics.

Call your doctor if your symptoms do not improve after 7 to 10 days of treatment, or if you have a fever with a headache, cough, or skin rash.

Apply the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Pregnancy level


Related drugs

Gentamicin , Tobramycin , Garamycin

Ask a Pharmacist

User's questions
    No comments yet.