Zymaxid (Gatifloxacin) - Ophthalmic

What Is Zymaxid?

Zymaxid (gatifloxacin ophthalmic solution ) 0.5% is an eye drop used to treat bacterial conjunctivitis, an eye infection caused by bacteria. Conjunctivitis itself is the inflammation or infection of the conjunctiva. This is the clear membrane that covers the white part of your eye.

Zymaxid belongs to a class of antibiotics called fluoroquinolones. It works by inhibiting two important enzymes called DNA gyrase and topoisomerase IV. These are proteins that bacteria rely on to replicate and survive.

Gatifloxacin is a prescription drug, which means you can’t purchase it over-the-counter. You’ll need an order for it from your healthcare provider and will pick it up from your pharmacy. It’s also available as a generic product under the name gatifloxacin.

Drug Facts

Generic Name: Gatifloxacin

Brand Name: Zymaxid 

Drug Availability: Prescription

Therapeutic Classification: Fluoroquinolone

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Ophthalmic

Active Ingredient: Gatifloxacin

Dosage Form: Ophthalmic solution

What Is Zymaxid Used For?

The Food and Drug Administration (FDA) approved Zymaxid to treat bacterial conjunctivitis caused by strains of susceptible bacteria in people at least 1-year-old. Strains are specific subtypes of bacteria. Being susceptible to Zymaxid means these individual bacteria species can be killed by it.

Gatifloxacin is active mostly against gram-positive bacteria species including Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mitis group, Streptococcus oralis, and Streptococcus pneumoniae. It does also cover one gram-negative type of bacteria called Haemophilus influenzae.

It’s important to note that an antibiotic eye drop like gatifloxacin will not be used for a viral eye infection, another very common type of pink eye.

Since conjunctivitis can have several causes, you’ll want to see a healthcare provider to ensure you get the proper treatment.

Zymaxid (Gatifloxacin) Drug Information: A close up of a person's face showing the eye

Verywell / Zoe Hansen

How to Take Zymaxid

You will most likely have to give yourself gatifloxacin eye drops frequently for each day of your treatment, ranging from every two to every four hours. Fortunately, about a week of treatment is usually sufficient to clear the infection, but make sure to follow your healthcare provider’s instructions carefully regarding how long to use it.

Always wash your hands before using eye drops. Use your thumb and index finger to gently pull your lower eyelid down and form a pocket. Place one or two drops (whichever you are instructed) into this pouch formed in the lower lid, not directly onto your eyeball. Be careful not to touch the tip of the dropper bottle to your eye or fingers.

If instructed, you can close your eyes for one to three minutes to make sure the medicine is absorbed. Your healthcare provider will let you know if you need to use Zymaxid in just one eye or both.

If you are a contact lens wearer, do not wear your lenses for the entire duration of your conjunctivitis treatment. When your infection has cleared and you are ready to put your contacts in, put in a brand new pair.


Store your Zymaxid bottle at room temperature (59 F to 77 F) with the lid closed tightly. Do not leave Zymaxid out in the heat or direct sunlight. Do not refrigerate, freeze, or shake the dropper bottle either.

If you’re traveling by plane, keep gatifloxacin in your carry-on luggage in case your checked baggage gets lost.

How Long Does Zymaxid Take to Work?

You may start to experience some relief from irritating eye symptoms like redness and itching within a few days of starting to use Zymaxid, or it may take longer for your symptoms to improve.

To ensure the best treatment, use it exactly as prescribed. This may require you to set alarm reminders on your phone since the medicine needs to be given quite frequently.

Make sure you finish the entire course of treatment with gatifloxacin even if you feel like your infection has cleared. This will prevent antibiotic resistance and help ensure that your infection doesn't return.

What Are the Side Effects of Zymaxid?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

If you experience any of these effects or feel your infection is not improving, consult your healthcare provider. You may need to stop gatifloxacin and start a different treatment.

These are the most common side effects of Zymaxid:

  • Worsening of conjunctivitis
  • Eye irritation or pain
  • Dysgeusia, an altered or impaired sense of taste where all foods may taste sour, sweet, bitter, or metallic

Severe Side Effects

Call your healthcare provider right away if you have serious side effects such as any of the following. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency.

Severe side effects of this medication can include:

  • Chemosis, when the eyelid swells and looks similar to a big blister
  • Conjunctival hemorrhage, a bright red patch in the white area of your eye that may result from a broken blood vessel
  • Increased lacrimation, or the involuntary production of excess tears
  • Keratitis, which is inflammation or irritation of the cornea, the very front part of your eye that covers your pupil and iris
  • Papillary conjunctivitis, when small bumps and irritation occur on the inside of your eyelid
  • Reduced visual acuity, an impairment or negative change in your vision

Long-Term Side Effects

Using Zymaxid for longer than prescribed may result in the growth of resistant bacteria or bacteria that Zymaxid cannot kill. If you feel a new infection is growing, consult your healthcare provider immediately, as you will most likely need to discontinue use and start a new therapy.

Report Side Effects

Zymaxid may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Zymaxid Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For ophthalmic dosage form (eye drops):
    • For bacterial conjunctivitis:
      • Zymar®:
        • Adults and children—
          • Days 1 and 2: Put 1 drop in the affected eye every 2 hours while awake, up to 8 times a day.
          • Days 3 through 7: Put 1 drop in the affected eye up to 4 times a day while awake.
      • Zymaxid®:
        • Adults and children 1 year of age and older—
          • Day 1: Put 1 drop in the affected eye every 2 hours while awake, up to 8 times.
          • Days 2 through 7: Put 1 drop in the affected eye 2 to 4 times a day while awake.
        • Children younger than 1 year of age—Use and dose must be determined by your doctor.


Under certain circumstances, you may need to modify or adjust your treatment with Zymaxid.

These are common instances that can affect the use of some medications:

  • Pregnancy and nursing: It is not well known or well studied whether Zymaxid poses a risk in human pregnancy or if it shows up in human breast milk. It should be used during pregnancy or when nursing only if the benefit of treatment outweighs any potential risk to the fetus or infant.
  • Children: Zymaxid has been proven safe and effective in children 1 year or older but not below age 1.
  • Older populations (ages 65 and older): No differences in side effects were seen between younger and older people (over age 65). However, not enough older people were included in trials to know if they may be affected differently.

Missed Dose

Do your best not to miss doses of Zymaxid, as it is important to maintain a certain level of gatifloxacin in your eye to kill the bacteria causing your infection. If you miss a dose, administer the missed one unless it is closer to the time of your next dose. In that case, skip the missed dose and proceed with the next ones as scheduled.

Overdose: What Happens If I Take Too Much Zymaxid?

If you take Zymaxid only as directed, you shouldn’t be concerned about using too much or overdosing. Keep a schedule written down or set reminders on your phone for when to take your doses.

What Happens If I Overdose on Zymaxid?

If you think you or someone else may have overdosed on Zymaxid, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Zymaxid, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

If your or your child's eye infection does not improve within a few days, or if it becomes worse, check with your doctor.

This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you or your child have a rash, itching, red or swollen skin around the eye or eyelid, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

Serious skin reactions can occur with this medicine. Check with your doctor right away if you or your child have blistering, peeling, or loose skin, red skin lesions, severe acne or skin rash, sores or ulcers on the skin, or fever or chills while you are using this medicine.

What Are Reasons I Shouldn't Take Zymaxid?

You shouldn’t use Zymaxid if you have a known hypersensitivity or allergy to fluoroquinolone antibiotics, such as ciprofloxacin or levofloxacin. You will also need to avoid wearing contact lenses for the entire duration of your treatment with Zymaxid until your eye infection clears.

What Other Medications Interact With Zymaxid?

Since Zymaxid is an eye drop, you are receiving a minimal dose of medicine. Little to no gatifloxacin gets absorbed into your system to interact with other drugs you take by mouth.

Even so, let your healthcare provider know about other medicines you take, especially any other eye drops, while you’re using Zymaxid.

What Medications Are Similar?

Gatifloxacin is not the only fluoroquinolone antibiotic available as an eye drop. A few other fluoroquinolones that come in this dosage form include:

  • Ciloxan (ciprofloxacin)
  • Levaquin (levofloxacin)
  • Ocuflox (ofloxacin)
  • Vigamox (moxifloxacin)

This is a list of drugs also prescribed for bacterial conjunctivitis. It is not a list of drugs recommended to take with Zymaxid. You should not take these drugs together. Ask your pharmacist or a healthcare provider if you have questions.

Frequently Asked Questions

  • What is Zymaxid used for?

    Zymaxid is an eye drop used to treat bacterial conjunctivitis, or an infection of the conjunctiva. This is the clear membrane that covers the white part of your eye. Zymaxid should not be used to treat viral, allergic, or chemical conjunctivitis.

  • How does Zymaxid work?

    Zymaxid, or gatifloxacin, is a fluoroquinolone antibiotic. It works by inhibiting two important enzymes that bacteria rely on to replicate and survive. These enzymes are called DNA gyrase and topoisomerase IV.

  • How should I stop taking Zymaxid?

    Take Zymaxid exactly as your healthcare provider prescribes it for you and as long as they prescribe it for you. Stopping Zymaxid before completing the full course of treatment can lead to antibiotic resistance, further infections, or the return of your current infection.

How Can I Stay Healthy While Taking Zymaxid?

Eye infections can be annoying and sometimes majorly affect your day-to-day activities, especially if you are a contact lens wearer.

Fortunately, most cases of bacterial conjunctivitis are pretty treatable, and symptoms usually begin to resolve within a few days of proper treatment.

As you treat your eye infection, keep your hands clean, and don’t touch the tip of the dropper on your hands, eyes, or any other surface. Don’t wear contact lenses while treating an eye infection, as they can interfere with the infection clearing. Make sure to put in new contacts once your infection is cleared up, as your old ones most likely have bacteria you don’t want to reintroduce into your eyes.

Finally, as with any antibiotic, complete your entire course of treatment even if you feel much better or are back to normal. Doing this will help to avoid the development of antibiotic resistance and make sure your infection is fully cleared.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Zymaxid label.

  2. American Optometric Association. Conjunctivitis (pink eye).

  3. MedlinePlus. Gatifloxacin Ophthalmic.

By Sara Hoffman, PharmD
Sara is a clinical pharmacist that believes everyone should understand their medications, and aims to achieve this through her writing.