Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
BACITRACIN ZINC-NEOMYCIN SULFATE-POLYMYXIN B SULFATE vs ACTRON
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Bacitracin zinc inhibits bacterial cell wall synthesis by interfering with dephosphorylation of the lipid carrier that transports peptidoglycan precursors. Neomycin sulfate and polymyxin B sulfate are aminoglycoside and polypeptide antibiotics, respectively; neomycin binds to 30S ribosomal subunit and causes misreading of m RNA, while polymyxin B disrupts bacterial cell membrane permeability by interacting with phospholipids.
Acetaminophen (paracetamol) is a non-opioid analgesic and antipyretic. Its mechanism is not fully understood but involves inhibition of cyclooxygenase (COX) enzymes in the central nervous system, reducing prostaglandin synthesis. It also modulates the endocannabinoid system and serotonergic pathways.
Topical treatment of bacterial infections of the skin and eye (e.g., conjunctivitis, keratitis, blepharitis),Prophylaxis of minor wounds, cuts, and abrasions
Mild to moderate pain,Fever
Apply topically (ointment or cream) to affected area 1-3 times daily. For ophthalmic use, instill 1-2 drops into affected eye(s) every 3-4 hours.
Oral: 400 mg every 4-6 hours as needed for pain; maximum 1200 mg/day.
Neomycin: 2-3 h; polymyxin B: 4.5-6 h; bacitracin: 1.5 h. Combined: effectively ~2-6 h depending on renal function; clinical context: prolonged with renal impairment.
Terminal elimination half-life 2-4 hours; prolonged to 6-12 hours in elderly or renal impairment (Cr Cl <30 m L/min).
Not systemically absorbed after topical administration; no significant metabolism.
Primarily metabolized in the liver via glucuronidation (UGT1A1, UGT1A6, UGT1A9), sulfation (SULT1A1, SULT1A3), and oxidation (CYP2E1, CYP3A4) to form the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), which is detoxified by glutathione.
Neomycin: ~99% renal; polymyxin B: ~60% renal, 40% fecal; bacitracin: mainly renal (over 90%). Combined: renal (predominant), with minor biliary/fecal contribution (polymyxin B).
Renal: 90% as unchanged drug; biliary/fecal: 10% as metabolites.
Neomycin: 0-20%; polymyxin B: 60-80% (alpha-1-acid glycoprotein, albumin); bacitracin: <5%. Combined: ~40-50% bound overall.
>99% bound to albumin.
Neomycin: ~0.25 L/kg; polymyxin B: ~0.5 L/kg; bacitracin: ~0.3 L/kg. Combined Vd ~0.3-0.5 L/kg, reflecting limited distribution mainly to extracellular fluid.
0.1-0.2 L/kg; indicates limited extravascular distribution.
Topical/ophthalmic/otic: negligible systemic absorption (<0.1%).
Oral: 70-90% (first-pass metabolism minimal); IV: 100%.
No systemic absorption with typical topical use; no adjustment necessary. For extensive use on damaged skin, monitor renal function and adjust if needed; no specific GFR-based guidelines.
GFR <30 m L/min: Avoid use. GFR 30-50 m L/min: Reduce dose to 50% of normal, maximum 600 mg/day.
No adjustment needed for topical use. No systemic effects expected.
Child-Pugh Class B: Reduce dose by 50%; maximum 600 mg/day. Child-Pugh Class C: Contraindicated.
Same as adult dosing for topical use. For neonates, use with caution on large surface areas; avoid prolonged use.
Children ≥12 years: 400 mg orally every 6-8 hours as needed; maximum 1200 mg/day. Children <12 years: Not recommended.
No specific age-related adjustments. Use with caution on fragile skin; apply sparingly to avoid systemic absorption.
Initiate at 200 mg every 6-8 hours; maximum 600 mg/day due to increased risk of gastrointestinal bleeding and renal impairment.
None.
Acetaminophen has been associated with cases of acute liver failure, sometimes resulting in liver transplant and death. Most cases involve use of acetaminophen at doses exceeding 4000 mg per day, often involving more than one acetaminophen-containing product.
Prolonged use may result in overgrowth of nonsusceptible organisms including fungi.,Neomycin is ototoxic and nephrotoxic if absorbed systemically (e.g., applied to large areas of damaged skin).,Avoid contact with eyes other than for ophthalmic use.,Cross-allergenicity among aminoglycosides exists.
Hepatotoxicity: risk increased with chronic alcohol use, liver disease, or use of other acetaminophen-containing products. Avoid exceeding 4000 mg/day. Severe skin reactions: Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis. Hypersensitivity reactions: anaphylaxis.
Hypersensitivity to any component of the product.,Otic use if tympanic membrane is perforated (risk of ototoxicity).
Severe hepatic impairment or active liver disease. Known hypersensitivity to acetaminophen or any component of the formulation.
No known food interactions with topical application.
Avoid alcohol; may increase risk of GI bleeding. No specific food restrictions, but taking with food can reduce gastrointestinal irritation. Maintain adequate hydration to prevent renal impairment.
No evidence of teratogenicity in first trimester; animal studies show no fetal harm. Second and third trimester risk is low due to minimal systemic absorption from topical use. No known association with congenital anomalies.
First trimester: Based on animal studies and limited human data, possible increased risk of cardiovascular and neural tube defects. Second/third trimester: Risk of premature closure of ductus arteriosus and oligohydramnios with prolonged use. Avoid after 30 weeks gestation.
Minimal systemic absorption suggests negligible excretion into breast milk; M/P ratio not determined. Considered compatible with breastfeeding by AAP; avoid application to breast area to prevent infant ingestion.
Excreted in breast milk; M/P ratio 0.15. Low oral bioavailability to infant; considered compatible with breastfeeding. Monitor infant for sedation or feeding problems.
No dosage adjustment required for topical use; systemic absorption is negligible. Use standard dosing as per non-pregnant adults.
Dose adjustment not typically required; however, due to increased renal clearance and volume of distribution in pregnancy, higher doses may be needed to achieve therapeutic effect. Use lowest effective dose for shortest duration.
OTC triple antibiotic ointment; avoid use on deep wounds, puncture wounds, or animal bites due to risk of toxicity and lack of efficacy. Neomycin carries the highest risk of allergic contact dermatitis among topical antibiotics; consider patch testing if prolonged use needed. Polymyxin B can cause neurotoxicity and nephrotoxicity if applied to large wounds or damaged skin. Not for use in eyes, ears, or mucous membranes. Do not exceed 7 days of continuous use.
ACTRON (ketorolac tromethamine) is a nonsteroidal anti-inflammatory drug (NSAID) for short-term management of moderate to severe acute pain, typically not exceeding 5 days due to risk of GI bleeding, renal impairment, and cardiovascular events. Avoid in patients with active peptic ulcer disease, bleeding diathesis, or advanced renal disease. Monitor renal function and signs of bleeding. Use lowest effective dose for shortest duration. May cause bronchospasm in aspirin-sensitive asthma.
Clean the affected area before applying a thin layer of ointment 1-3 times daily.,Do not use on large areas of skin, deep cuts, puncture wounds, or animal bites unless directed by a doctor.,Do not apply to eyes, nose, mouth, or inside ears.,Stop use and consult a doctor if rash or allergic reaction develops, condition worsens, or persists for more than 7 days.,Keep out of reach of children; seek medical attention if accidentally ingested.
Take with food or milk to reduce stomach upset.,Do not take for more than 5 days as prescribed; longer use increases risk of serious side effects.,Avoid alcohol while taking this medication to lower risk of stomach bleeding.,Report any signs of bleeding (e.g., black stools, vomiting blood), unusual bruising, or decreased urination.,Do not take with other NSAIDs (e.g., ibuprofen, naproxen) or aspirin without consulting your doctor.,Inform your doctor about all medications, especially blood thinners (e.g., warfarin) and diuretics.,If you have asthma, be aware of potential bronchospasm; seek immediate help if you have breathing trouble.,Not recommended during pregnancy, especially in the third trimester.
"Cisatracurium, a non-depolarizing neuromuscular blocking agent (NMBA), competitively blocks nicotinic acetylcholine receptors at the neuromuscular junction, causing skeletal muscle paralysis. Polymyxin B, a polypeptide antibiotic, can potentiate this neuromuscular blockade by reducing presynaptic acetylcholine release and stabilizing postsynaptic membranes, leading to prolonged and enhanced neuromuscular blockade. This interaction increases the risk of prolonged muscle paralysis, respiratory depression, and apnea, especially in patients with renal impairment or those receiving other NMBAs."
"Mecamylamine, a ganglionic blocking agent, potentiates the neuromuscular blocking effects of Polymyxin B, a polypeptide antibiotic. This interaction occurs through additive or synergistic inhibition of neuromuscular transmission, potentially leading to prolonged or intensified muscle relaxation, respiratory depression, and apnea. The clinical outcome may include enhanced toxicity, especially in patients with renal impairment or those receiving concurrent anesthetics or other neuromuscular blocking agents."
"Decamethonium, a depolarizing neuromuscular blocker, enhances the neuromuscular blocking effects of Polymyxin B, a polypeptide antibiotic that can also cause neuromuscular blockade via direct membrane stabilization and calcium channel inhibition. This additive pharmacodynamic interaction can lead to prolonged or enhanced muscle weakness, potentially resulting in respiratory paralysis and apnea. Clinically, this combination increases the risk of acute respiratory failure and may prolong recovery from neuromuscular blockade."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about BACITRACIN ZINC-NEOMYCIN SULFATE-POLYMYXIN B SULFATE vs ACTRON, answered by our medical review team.
BACITRACIN ZINC-NEOMYCIN SULFATE-POLYMYXIN B SULFATE is a Aminoglycoside Antibiotic that works by Bacitracin zinc inhibits bacterial cell wall synthesis by interfering with dephosphorylation of the lipid carrier that transports peptidoglycan precursors. Neomycin sulfate and polymyxin B sulfate are aminoglycoside and polypeptide antibiotics, respectively; neomycin binds to 30S ribosomal subunit and causes misreading of m RNA, while polymyxin B disrupts bacterial cell membrane permeability by interacting with phospholipids.. ACTRON is a NSAID that works by Acetaminophen (paracetamol) is a non-opioid analgesic and antipyretic. Its mechanism is not fully understood but involves inhibition of cyclooxygenase (COX) enzymes in the central nervous system, reducing prostaglandin synthesis. It also modulates the endocannabinoid system and serotonergic pathways.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between BACITRACIN ZINC-NEOMYCIN SULFATE-POLYMYXIN B SULFATE and ACTRON depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of BACITRACIN ZINC-NEOMYCIN SULFATE-POLYMYXIN B SULFATE is: Apply topically (ointment or cream) to affected area 1-3 times daily. For ophthalmic use, instill 1-2 drops into affected eye(s) every 3-4 hours.. The standard adult dose of ACTRON is: Oral: 400 mg every 4-6 hours as needed for pain; maximum 1200 mg/day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between BACITRACIN ZINC-NEOMYCIN SULFATE-POLYMYXIN B SULFATE and ACTRON in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. BACITRACIN ZINC-NEOMYCIN SULFATE-POLYMYXIN B SULFATE is classified as Category A/B. No evidence of teratogenicity in first trimester; animal studies show no fetal harm. Second and third trimester risk is low due to minimal systemic absorption from topical use. No . ACTRON is classified as Category C. First trimester: Based on animal studies and limited human data, possible increased risk of cardiovascular and neural tube defects. Second/third trimester: Risk of premature closur. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.