Polymix G

Approved Indications:

• Superficial skin infections caused by susceptible Gram-positive and Gram-negative bacteria.
• Minor cuts, abrasions, and burns at risk of bacterial contamination.
• Secondary bacterial infections in eczema or dermatitis.
• Otitis externa (external ear infections) caused by susceptible bacteria.
• Prophylaxis of infection in minor wounds or surgical incisions (topical).

Clinically Accepted Off-Label Uses:

• Treatment of acne lesions with secondary bacterial infection.
• Prevention of infection in minor dermatologic procedures.

Adults & Children (>2 years):

• Apply a thin layer to the affected area 2–3 times daily.
• Duration: Typically 7–10 days or until infection resolves.
• Avoid prolonged use to prevent local irritation or resistance.

Infants (<2 years):

• Use only under medical supervision due to potential systemic absorption of neomycin.

Special Populations:

• Renal impairment: No dose adjustment necessary for topical use, but systemic absorption risk should be considered for extensive skin lesions.
• Hepatic impairment: No dose adjustment required for topical administration.

Administration Notes:

• Clean and dry affected area before application.
• Avoid contact with eyes, mouth, and large open wounds.
• Wash hands after application.

Gramacidin + Neomycin + Polymyxin B combines three antibiotics with complementary mechanisms:

• Gramacidin disrupts bacterial cell wall synthesis, leading to bactericidal activity against Gram-positive organisms.
• Neomycin binds to the 30S ribosomal subunit, inhibiting bacterial protein synthesis, resulting in bactericidal effects primarily against Gram-negative bacteria.
• Polymyxin B interacts with the bacterial outer membrane of Gram-negative bacteria, increasing membrane permeability and causing cell lysis.
  The combination provides broad-spectrum coverage, effectively eliminating both Gram-positive and Gram-negative bacteria in superficial infections.

• Absorption: Minimal systemic absorption from intact skin; higher absorption possible through large wounds or burns.
• Distribution: Limited to the application site; systemic distribution negligible under normal use.
• Metabolism: Not significantly metabolized due to minimal systemic absorption.
• Excretion: Excreted primarily via renal route if absorbed systemically.
• Onset of Action: Rapid bactericidal activity at the site of infection.
• Half-life: Not clinically relevant for topical application.

• Pregnancy: Generally considered Category C—topical use is preferred only if clearly needed; systemic absorption is minimal but caution is advised.
• Lactation: Topical use is considered safe; minimal absorption into breast milk. Avoid application on large areas or broken skin during breastfeeding.

• Primary Class: Topical Antibiotic
• Subclass: Combination antibiotic for superficial skin infections

• Known hypersensitivity to gramacidin, neomycin, polymyxin B, or any excipients.
• History of aminoglycoside-induced nephrotoxicity or ototoxicity.
• Open wounds with extensive tissue damage unless directed by a physician.

• High-risk patients:
• Individuals with renal or hepatic impairment (due to potential systemic absorption).
• Patients with pre-existing auditory or vestibular dysfunction.
• Serious risks:
• Rare risk of systemic toxicity if applied to large wounds or used excessively.
• Monitoring:
• Watch for signs of local hypersensitivity (rash, itching, burning).
• Discontinue if severe irritation occurs.

Common:

• Mild burning, itching, or redness at application site.
• Dryness or peeling of skin.

Serious/Rare:

• Allergic reactions: rash, swelling, anaphylaxis (rare).
• Ototoxicity or nephrotoxicity with prolonged or extensive use, primarily due to neomycin.

• Drug-Drug: Avoid concurrent topical use with other nephrotoxic or ototoxic agents on large areas.
• Drug-Food: No significant interactions.
• Drug-Alcohol: No interaction with topical alcohol-based products, but excessive use may increase local irritation.
• Enzyme systems: Not metabolically significant; CYP450 not involved.

• Current guidelines emphasize short-term use to minimize resistance and toxicity.
• FDA and WHO recommend avoiding prolonged use on large skin surfaces due to potential systemic aminoglycoside absorption.
• Newer clinical guidance suggests combination topical therapy only for confirmed bacterial infections and not for routine prophylaxis.

• Store at 20°C–25°C (room temperature).
• Protect from moisture and direct light.
• Do not freeze.
• Keep container tightly closed when not in use.
• For creams or ointments, avoid contamination by not touching the tip of the tube to skin or wound.