Besivance Drug Interactions: What to Avoid and What to Tell Your Doctor

One of the first questions patients ask when starting a new medication is: "Will this interact with anything else I'm taking?" For Besivance (besifloxacin 0.6% ophthalmic suspension), the good news is that drug interactions are minimal. Here's what the research shows, what you need to tell your doctor, and what precautions to take during your 7-day treatment course.

Why Besivance Has Minimal Drug Interactions

The key reason Besivance has very few drug interactions is that it is a topical ophthalmic medication applied directly to the eye surface. Systemic absorption from topical ophthalmic use is extremely low — measurable blood levels of besifloxacin following recommended dosing are essentially undetectable in clinical studies. This means Besivance does not meaningfully interact with drugs you take by mouth, injection, or other routes.

As stated in the FDA-approved labeling: there are no known severe, serious, or moderate drug interactions with besifloxacin ophthalmic.

Key Precaution: Other Eye Drop Medications

The most clinically relevant "interaction" for Besivance is with other topical ophthalmic medications — not because of a chemical drug-drug interaction, but because of a practical timing issue. If you're using any other eye drops (for glaucoma, dry eye, allergies, or any other condition), you need to wait at least 5 minutes between instilling each drop.

Why 5 minutes? Each drop needs time to be absorbed by the eye tissues before the next drop is instilled. Applying multiple drops in rapid succession causes the first drops to be washed out before they can work properly, reducing effectiveness.

Contact Lenses: A Critical Precaution

Do not wear contact lenses during Besivance treatment and while you have signs or symptoms of an eye infection. This is not a drug-drug interaction per se, but it is an important practical precaution. Soft contact lenses can absorb ophthalmic preservatives and may be permanently stained or damaged. More importantly, wearing contact lenses during an active eye infection can worsen the infection and delay healing.

Ask your doctor when it's safe to resume wearing contact lenses after completing your course of Besivance.

Fluoroquinolone Allergy: A Contraindication, Not an Interaction

If you have a known allergy to besifloxacin or to other fluoroquinolone antibiotics (such as ciprofloxacin, levofloxacin, moxifloxacin, or ofloxacin), you should not use Besivance. Cross-reactivity among fluoroquinolones is possible. This is a contraindication — tell your prescriber and pharmacist about any fluoroquinolone allergy before starting Besivance.

Pregnancy and Breastfeeding Considerations

There is limited human safety data for Besivance during pregnancy and breastfeeding. Because systemic absorption from topical ophthalmic use is very low, the risk to a fetus or nursing infant is considered minimal. However, there is not enough data to definitively rule out risk. Always tell your prescriber if you are pregnant, planning to become pregnant, or breastfeeding before using Besivance.

What to Tell Your Doctor and Pharmacist Before Using Besivance

Before starting Besivance, always inform your healthcare team about:

Any allergy to besifloxacin or other fluoroquinolone antibiotics

All other eye drop medications you are currently using

All prescription medications, over-the-counter drugs, vitamins, supplements, and herbal products you take

Pregnancy or breastfeeding status

Any history of prior antibiotic eye drop treatment failure or eye infections that were difficult to treat

Alcohol and Food Interactions

There are no known interactions between Besivance eye drops and food, alcohol, or beverages. Since the medication is applied to the eye and is not taken by mouth, typical food-drug or alcohol-drug interactions do not apply.

Prolonged Use Warning: Risk of Superinfection

Using Besivance for longer than the prescribed 7 days can allow growth of non-susceptible organisms — bacteria or fungi that besifloxacin cannot kill. This can lead to a new (superinfection) on top of your original infection. Always follow your doctor's prescribed course length and do not use leftover Besivance for future infections without a new prescription.

The Bottom Line

Besivance has an excellent safety profile with no known severe or moderate drug interactions. The most important precautions are: wait 5 minutes between eye drops if using multiple ophthalmic medications, avoid contact lenses during treatment, and do not use it if you have a fluoroquinolone allergy. For more on side effects, see our guide to Besivance side effects.