Polymyxin-b-and-trimethoprim Ophthalmic Solution

Polymyxin B Sulfate and Trimethoprim Ophthalmic Solution, USP* is a sterile antimicrobial solution for topical ophthalmic use. It has a pH of 4.0 to 6.2 and osmolality of 270 to 310 mOsm/kg.

Chemical Names: Trimethoprim sulfate, 2,4-diamino-5-(3,4 5-trimethoxybenzyl)pyrimidine sulfate (2:1), is a white, odorless, crystalline powder with a molecular weight of 678.72 and the following structural formula:

C28H38N8O10S
Mol. Wt. 678.72

Polymyxin B sulfate is the sulfate salt of polymyxin B1 and B2 which are produced by the growth of Bacillus polymyxa  (Prazmowski) Migula (Fam. Bacillaceae). It has a potency of not less than 6,000 polymyxin B units per mg, calculated on an anhydrous basis. The structural formula is:

Each mL contains: ACTIVES: Polymyxin B Sulfate equal to 10,000 polymyxin B units, Trimethoprim Sulfate (equivalent to trimethoprim 1 mg); INACTIVES: Purified Water, Sodium Chloride. Sulfuric acid and, if necessary, sodium hydroxide may be added to adjust pH (4.0 – 6.2). PRESERVATIVE ADDED: Benzalkonium Chloride 0.004%.

Polymyxin B sulfate and trimethoprim ophthalmic solution is contraindicated in patients with known hypersensitivity to any of its components.

In mild to moderate infections, instill one drop in the affected eye(s) every three hours (maximum of 6 doses per day) for a period of 7 to 10 days.

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Side effects that you should report to your doctor or health care professional as soon as possible:

• burning, stinging, or swelling
• change in vision or blurred vision that will not go away
• eye pain
• itching and redness
• rash

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

• temporary blurred vision after applying
• temporary watering or stinging

Interactions are not expected. Do not use any other eye products without advice of your doctor or health care professional.