Besivance Side Effects: What to Expect and When to Call Your Doctor

Besivance (besifloxacin 0.6% ophthalmic suspension) is generally well-tolerated, but like any medication, it can cause side effects. Because Besivance is applied directly to the eye surface, most side effects are localized — you won't experience the systemic effects you'd see with an oral antibiotic. Here's what to expect when using Besivance, and the warning signs that should prompt a call to your doctor.

How Common Are Besivance Side Effects?

Clinical trials involving approximately 1,000 patients between ages 1 and 98 showed that Besivance is well-tolerated. The vast majority of patients complete the 7-day treatment without significant adverse effects. Side effects, when they occur, are typically mild and temporary.

Common Side Effects of Besivance (Mild)

The following side effects were reported in clinical trials in approximately 1–2% of patients:

Conjunctival redness (most common, ~2% of patients) — Some redness is also a symptom of the infection being treated, making it difficult to distinguish from the infection itself.

Blurred vision — Usually brief and occurs immediately after instilling the drop due to the suspension's viscous DuraSite formulation. This is expected and resolves within a few minutes.

Eye pain or discomfort — Mild stinging or burning upon instillation is common and typically brief.

Eye irritation — A sensation of something in the eye may occur but usually resolves quickly.

Itchy eye (pruritus) — Mild itching during treatment is not uncommon.

Headache — Reported in a small percentage of patients; typically mild.

About the Temporary Blurred Vision After Each Dose

Besivance is formulated with DuraSite, a mucoadhesive polymer that gives the suspension a thick, gel-like consistency. When you instill a drop, you may notice a gray-white coating on the eye and brief blurring of vision — this is completely normal and expected. This temporary blurring typically resolves within 1–3 minutes as the drop distributes across the ocular surface. Plan to instill drops when you don't need clear vision immediately (not while driving or operating machinery).

Serious Side Effects — Call Your Doctor or Seek Emergency Care

While rare, the following serious reactions require immediate medical attention:

Severe allergic reaction: Hives, difficulty breathing, swelling of face, lips, tongue, or throat. Stop using Besivance immediately and seek emergency care.

Worsening eye infection: If your eye symptoms are not improving within 2–3 days or are getting worse, stop treatment and call your doctor. This could indicate a resistant organism, a viral infection, or a superinfection.

Superinfection with resistant organisms: Prolonged use of Besivance beyond 7 days may allow overgrowth of fungi or non-susceptible bacteria. If you develop new symptoms after initial improvement, contact your doctor.

Sudden vision loss or visual changes: Not expected with Besivance for conjunctivitis, but any sudden changes in vision require urgent evaluation.

Important Precautions During Treatment

Do not wear contact lenses while you have signs of an eye infection or during Besivance treatment. A preservative in soft contact lens solutions could interact with the lens material.

Do not inject into the eye. Besivance is for topical ophthalmic use only.

Complete the full 7-day course even if symptoms improve early. Stopping early can lead to treatment failure and potential resistance.

Wait 5 minutes between eye drops if you are using other ophthalmic medications concurrently.

Pregnancy and Breastfeeding

There are no adequate human studies of Besivance during pregnancy or breastfeeding. Animal studies of oral besifloxacin did not show fetal harm at clinically relevant exposures — but systemic absorption from topical ophthalmic use is very low. If you are pregnant or breastfeeding, discuss the risks and benefits with your doctor before using Besivance.

The Bottom Line

Besivance is well-tolerated, and serious side effects are rare. The most common experience is brief blurring immediately after use — a normal effect of the DuraSite formulation. If your symptoms worsen after 2–3 days, contact your doctor. For information on drug interactions, see our guide to Besivance drug interactions.