Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
WELLCOVORIN vs BACITRACIN-NEOMYCIN-POLYMYXIN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Folinic acid (leucovorin) is a reduced form of folic acid that bypasses dihydrofolate reductase inhibition, providing cofactors for nucleotide synthesis and reversing the effects of folate antagonists such as methotrexate.
Bacitracin inhibits bacterial cell wall synthesis by interfering with dephosphorylation of the lipid carrier that transports peptidoglycan precursors. Neomycin and polymyxin B are aminoglycoside and polypeptide antibiotics, respectively; neomycin binds to the 30S ribosomal subunit, causing misreading of m RNA and inhibiting protein synthesis, while polymyxin B disrupts bacterial cell membrane integrity by interacting with lipopolysaccharides and phospholipids, leading to increased permeability and cell death.
Rescue therapy after high-dose methotrexate therapy in osteosarcoma,Treatment of advanced colorectal cancer in combination with fluorouracil (off-label),To diminish toxicity and counteract effects of folic acid antagonists (e.g., trimethoprim, pyrimethamine) in certain infections
Treatment of superficial bacterial infections of the skin and mucous membranes (e.g., wounds, burns, impetigo, folliculitis),Prophylaxis of minor skin abrasions and wounds to prevent infection,Off-label: Use in conjunctival irrigation or ophthalmic infections (as combination ophthalmic preparations)
WELLCOVORIN (levoleucovorin) is administered intravenously or intramuscularly at a dose of 7.5 mg (approximately 0.1 mg/kg) every 6 hours for 10 doses starting 24 hours after the end of methotrexate infusion. Alternatively, 15 mg orally every 6 hours for 10 doses, starting 24 hours after methotrexate infusion.
Apply topically to affected area 2-5 times daily.
The terminal elimination half-life of folinic acid (active reduced folate) is approximately 6-7 hours in patients with normal renal function. The pharmacologically active metabolite, 5-methyltetrahydrofolate, has a longer half-life of about 10-12 hours. In renal impairment, half-life may be prolonged.
Bacitracin: 1.5 hours (prolonged in renal impairment); Neomycin: 2-3 hours (accumulates with renal dysfunction); Polymyxin B: 6-9 hours (increased in renal impairment).
Folinic acid is metabolized via reduction and methylation to active folate forms (e.g., 5-methyltetrahydrofolate) in the liver and other tissues. Involves dihydrofolate reductase and other folate-metabolizing enzymes.
Not extensively metabolized. Systemic absorption from topical application is minimal; absorbed drug may undergo hepatic metabolism or be excreted renally unchanged.
Primarily renal excretion as unchanged drug and metabolites; about 80-90% of a dose is excreted in urine within 24 hours, with approximately 50-70% as unchanged folinic acid and the remainder as 5-methyltetrahydrofolate and other metabolites. Fecal excretion accounts for <10%.
Bacitracin: primarily renal (>90% unchanged); Neomycin: renal (30-50% unchanged) with non-renal clearance; Polymyxin: renal excretion of parent drug (60-80% unchanged) with some biliary and fecal elimination.
Approximately 15% bound to plasma proteins, mainly albumin. Binding is not extensive.
Bacitracin: <10% bound to plasma proteins; Neomycin: 0-30% bound; Polymyxin B: 50-70% bound, primarily to alpha-1-acid glycoprotein and lipoproteins.
Volume of distribution is approximately 0.5-0.6 L/kg, indicating distribution into total body water and some tissue binding. It crosses the blood-brain barrier poorly.
Bacitracin: 0.3 L/kg (confined to extracellular fluid); Neomycin: 0.2-0.3 L/kg (low tissue penetration except renal cortex); Polymyxin B: 0.7-1.0 L/kg (extensive tissue binding).
Oral bioavailability is variable: approximately 25-30% for the active isomer (l-folinic acid) due to first-pass metabolism; the racemic mixture (d,l-folinic acid) has a lower absolute bioavailability of about 30% for the active component. Intravenous and intramuscular routes provide 100% bioavailability.
Oral: negligible (<1%) for all three components; topical: minimal systemic absorption via intact skin (<0.5%); ophthalmic/otic: minimal absorption via mucosal surfaces.
No specific GFR-based dose modifications are provided in the prescribing information. However, levoleucovorin is renally eliminated, and caution is advised in patients with renal impairment. For severe renal impairment (Cr Cl < 10 m L/min), consider dose reduction or extended interval. Monitor methotrexate levels and adjust leucovorin dose accordingly.
No systemic absorption; no dosage adjustment required.
No specific dose adjustments are recommended for hepatic impairment based on Child-Pugh class. However, caution is advised in patients with significant hepatic dysfunction due to potential altered folate metabolism.
No systemic absorption; no dosage adjustment required.
WELLCOVORIN is not FDA approved for pediatric use. However, in pediatric patients, levoleucovorin is sometimes used at a dose of 10 mg/m² (or 0.2 mg/kg) every 6 hours for 5-7 doses, starting 24 hours after methotrexate infusion, adjusted based on methotrexate levels. Dosing should be individualized based on clinical response and methotrexate concentration.
Apply topically to affected area 2-5 times daily; same as adult dose.
No specific geriatric dose adjustments are recommended. Due to age-related decline in renal function, monitor renal function and methotrexate levels closely, and consider dose adjustment based on creatinine clearance.
Apply topically to affected area 2-5 times daily; same as adult dose.
No FDA black box warning.
Not applicable for topical formulations. However, systemic use of bacitracin (rare) may cause nephrotoxicity and anaphylactic reactions. Neomycin may cause ototoxicity and nephrotoxicity with systemic absorption.
May mask pernicious anemia and other megaloblastic anemias due to vitamin B12 deficiency; caution in patients with renal impairment; hypersensitivity reactions; gastrointestinal toxicity with 5-FU combination.
Prolonged use may result in overgrowth of nonsusceptible organisms including fungi.,Topical use may cause allergic contact dermatitis, especially with neomycin.,Avoid application to large areas, open wounds, or damaged skin due to potential systemic absorption and toxicity.,Use with caution in patients with renal impairment or pre-existing hearing loss (neomycin component).,Ototoxicity and nephrotoxicity may occur if significant systemic absorption occurs.
History of severe hypersensitivity to folinic acid; pernicious anemia or other megaloblastic anemias secondary to vitamin B12 deficiency.
Hypersensitivity to any component (bacitracin, neomycin, polymyxin B) or other aminoglycosides/polypeptide antibiotics.,Ophthalmic use in eyes with corneal abrasions or perforation (relative).,Known history of neomycin-associated ototoxicity or nephrotoxicity.
No significant food interactions have been reported. However, maintain adequate hydration and avoid alcohol due to potential hepatotoxicity. No specific dietary restrictions are required.
No significant food interactions; topical application minimizes systemic absorption. No dietary restrictions.
WELLCOVORIN (levoleucovorin) is a folate analog. Folate is essential for fetal development. Wellcovorin is the active enantiomer of leucovorin, which is used to counteract folic acid antagonists. Available data do not indicate an increased risk of major birth defects with therapeutic doses. However, high-dose methotrexate therapy (which Wellcovorin is used to rescue from) is teratogenic. During first trimester, folate supplementation is protective against neural tube defects. During second and third trimester, folate requirements increase. No specific fetal risks are known from Wellcovorin alone. However, the underlying condition requiring treatment may pose risks.
Bacitracin-Neomycin-Polymyxin is a topical combination with negligible systemic absorption; thus, fetal risk is minimal. No known teratogenic effects reported; animal studies for individual components show no fetal harm at systemic doses. However, neomycin has theoretical risk of ototoxicity if systemically absorbed, but topical use is considered low risk. FDA Pregnancy Category C for components, but topical use deemed safe.
Levoleucovorin is excreted into human milk. The M/P ratio is not established. Due to low molecular weight, excretion is expected. Exposure to the breastfed infant is likely low. Caution is advised. Use only if clearly needed.
Minimal systemic absorption after topical application; excretion into breast milk is unlikely. M/P ratio not determined; safe for use during breastfeeding if applied to small areas and not to open wounds.
Pregnancy increases folate clearance. Dose may need adjustment to maintain adequate serum folate levels, especially in high-dose methotrexate rescue. Monitor serum folate and adjust dose accordingly. Specific dose changes are not established; clinical judgment and monitoring are required.
No dosing adjustments necessary for pregnancy. Pharmacokinetic changes due to pregnancy (e.g., increased skin blood flow, hydration) are not clinically significant for this topical combination. Standard topical application is appropriate.
WELLCOVORIN (levoleucovorin) is the active l-isomer of leucovorin; it does not require metabolic activation and is preferred in patients with dihydropyrimidine dehydrogenase (DPD) deficiency. It is used to reduce the toxicity of methotrexate (MTX) and to enhance the efficacy of fluorouracil (5-FU). When used for MTX rescue, initiate 24 hours after start of MTX infusion; monitor serum MTX levels, creatinine, and urine p H. Rescue dose and duration depend on MTX levels; continue until MTX level < 0.05 μmol/L. For 5-FU modulation, administer immediately before or simultaneously with 5-FU; do not use with irinotecan due to increased diarrhea risk.
Triple antibiotic ointment (bactiracin-neomycin-polymyxin) is first-line for prophylaxis of minor skin infections; avoid use on large areas, deep wounds, or burns due to risk of systemic absorption and nephrotoxicity. Neomycin carries high risk of allergic contact dermatitis; consider alternative in patients with known hypersensitivity. Topical use only; not for ophthalmic or intranasal application due to polymyxin ocular toxicity. Synergistic coverage includes Gram-positive (bacitracin), Gram-negative (polymyxin), and broad-spectrum (neomycin).
Take this medication exactly as prescribed; do not change the dose or frequency without consulting your doctor.,This drug may be given as an injection or as an oral tablet; follow the instructions for the specific formulation you receive.,If you miss a dose, contact your healthcare provider; do not double the next dose.,Report any signs of allergic reaction (rash, hives, swelling, difficulty breathing) or severe gastrointestinal symptoms (severe diarrhea, vomiting, abdominal pain) immediately.,Drink plenty of fluids to stay hydrated, especially during chemotherapy treatment.,Avoid alcohol while taking this medication as it may increase the risk of liver toxicity.,Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
Apply a thin layer to clean, minor cuts, scrapes, or burns 1-3 times daily.,Do not use on large body areas, deep puncture wounds, animal bites, or serious burns.,Stop use and consult doctor if rash, irritation, or signs of infection (worsening redness, swelling, pus) develop.,Avoid use on eyes, nose, or mouth; if contact occurs, rinse thoroughly with water.,Tell your doctor if you have kidney problems or are allergic to any of the ingredients (bacitracin, neomycin, polymyxin B).
No interactions on record
"The therapeutic efficacy of Picosulfuric acid can be decreased when used in combination with Bacitracin."
"Bacitracin may increase the nephrotoxic activities of Colistimethate."
"Bacitracin may increase the nephrotoxic activities of Streptomycin."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about WELLCOVORIN vs BACITRACIN-NEOMYCIN-POLYMYXIN, answered by our medical review team.
WELLCOVORIN is a Folic Acid Derivative that works by Folinic acid (leucovorin) is a reduced form of folic acid that bypasses dihydrofolate reductase inhibition, providing cofactors for nucleotide synthesis and reversing the effects of folate antagonists such as methotrexate.. BACITRACIN-NEOMYCIN-POLYMYXIN is a Aminoglycoside Antibiotic that works by Bacitracin inhibits bacterial cell wall synthesis by interfering with dephosphorylation of the lipid carrier that transports peptidoglycan precursors. Neomycin and polymyxin B are aminoglycoside and polypeptide antibiotics, respectively; neomycin binds to the 30S ribosomal subunit, causing misreading of m RNA and inhibiting protein synthesis, while polymyxin B disrupts bacterial cell membrane integrity by interacting with lipopolysaccharides and phospholipids, leading to increased permeability and cell death.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between WELLCOVORIN and BACITRACIN-NEOMYCIN-POLYMYXIN 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 WELLCOVORIN is: WELLCOVORIN (levoleucovorin) is administered intravenously or intramuscularly at a dose of 7.5 mg (approximately 0.1 mg/kg) every 6 hours for 10 doses starting 24 hours after the end of methotrexate infusion. Alternatively, 15 mg orally every 6 hours for 10 doses, starting 24 hours after methotrexate infusion.. The standard adult dose of BACITRACIN-NEOMYCIN-POLYMYXIN is: Apply topically to affected area 2-5 times daily.. 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 WELLCOVORIN and BACITRACIN-NEOMYCIN-POLYMYXIN 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. WELLCOVORIN is classified as Category C. WELLCOVORIN (levoleucovorin) is a folate analog. Folate is essential for fetal development. Wellcovorin is the active enantiomer of leucovorin, which is used to counteract folic ac. BACITRACIN-NEOMYCIN-POLYMYXIN is classified as Category A/B. Bacitracin-Neomycin-Polymyxin is a topical combination with negligible systemic absorption; thus, fetal risk is minimal. No known teratogenic effects reported; animal studies for i. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.