Polytrim is a combination of which antibiotics?

Polytrim is a combination of which antibiotics?

• A. Neomycin + Polymyxin B
• B. Trimethoprim + Polymyxin B
• C. Erythromycin + Polymyxin B
• D. Ofloxacin + Dexamethasone

Answer: (B)

Recognizing fixed-combination antibiotics used in eye care helps you know what Polytrim contains. Polytrim is a fixed combination of trimethoprim and polymyxin B. The two drugs work together because polymyxin B disrupts the bacterial outer membrane, especially affecting Gram-negative organisms, while trimethoprim blocks bacterial DNA synthesis by inhibiting dihydrofolate reductase. This complementary action provides broad coverage against the common pathogens causing conjunctivitis, including many Gram-positive cocci and Gram-negative rods, with dual mechanisms helping reduce resistance risk. Other antibiotic pairs listed involve different agents or include a steroid combination, so they don’t match Polytrim’s trimethoprim plus polymyxin B formulation.

Recognizing fixed-combination antibiotics used in eye care helps you know what Polytrim contains. Polytrim is a fixed combination of trimethoprim and polymyxin B. The two drugs work together because polymyxin B disrupts the bacterial outer membrane, especially affecting Gram-negative organisms, while trimethoprim blocks bacterial DNA synthesis by inhibiting dihydrofolate reductase. This complementary action provides broad coverage against the common pathogens causing conjunctivitis, including many Gram-positive cocci and Gram-negative rods, with dual mechanisms helping reduce resistance risk.

Other antibiotic pairs listed involve different agents or include a steroid combination, so they don’t match Polytrim’s trimethoprim plus polymyxin B formulation.