From the FDA Drug Label
Instill one drop in the affected eye 3 times a day for 7 days. The dosing of moxifloxacin eye drops is 3 times a day, not 5 times daily 1.
From the Research
Moxifloxacin eye drops are typically dosed 3 times daily, not 5 times daily. The standard dosing regimen for generic moxifloxacin ophthalmic solution (0.5%) is one drop in the affected eye(s) three times per day for 7 days, though treatment duration may vary based on the specific eye infection being treated. For certain severe infections, some prescribers might initially recommend more frequent administration, but the standard maintenance dosing remains three times daily. This dosing schedule is effective because moxifloxacin is a fourth-generation fluoroquinolone antibiotic with excellent ocular penetration and a relatively long half-life in ocular tissues, allowing for less frequent dosing compared to some other antibiotic eye drops. According to the most recent study 2, moxifloxacin has a lower MIC and half inhibitory concentration values and a larger inhibition zone for all the strain tested, with high performance in controlling gram-negative growth. Additionally, a study from 3 suggests that the high potency and mean concentration in conjunctival tissue combined with the long residence time of topical moxifloxacin enables a dosing strategy of three times daily for 5 days. Patients should complete the full course of treatment even if symptoms improve before completion to ensure complete eradication of the infection and prevent antibiotic resistance. It's also worth noting that moxifloxacin has been shown to have a significant effect on nasal flora when applied topically to the ocular surface, as demonstrated in a study from 4. Overall, the standard dosing regimen of three times daily is supported by the available evidence and is effective in treating bacterial eye infections while minimizing the risk of antibiotic resistance.