Comparative Pharmacology
Head-to-head clinical analysis: TERRAMYCIN W POLYMYXIN B SULFATE versus TERRAMYCIN POLYMYXIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: TERRAMYCIN W POLYMYXIN B SULFATE versus TERRAMYCIN POLYMYXIN.
TERRAMYCIN W/ POLYMYXIN B SULFATE vs TERRAMYCIN-POLYMYXIN
Head-to-head clinical comparison of therapeutic indices and safety profiles.
Oxytetracycline: inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, blocking aminoacyl-tRNA binding. Polymyxin B sulfate: disrupts bacterial cell membrane permeability by binding to lipopolysaccharides in Gram-negative bacteria.
Terramycin (oxytetracycline) inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, preventing aminoacyl-tRNA attachment. Polymyxin disrupts bacterial cell membrane permeability by binding to lipopolysaccharides, leading to cell death.
Ocular infections caused by susceptible organisms (e.g., conjunctivitis, blepharitis)
Ophthalmic infections caused by susceptible organismsSuperficial ocular infections (conjunctivitis, blepharitis)Prophylaxis of neonatal conjunctivitis due to Neisseria gonorrhoeae or Chlamydia trachomatis
1-2 g oxytetracycline (as hydrochloride) plus 100,000-250,000 units polymyxin B sulfate IM every 8-12 hours (deep IM only); ophthalmic: 1-2 drops suspension every 4-6 hours; topical: apply thin layer to affected area 2-4 times daily.
Adults: 1-2 drops into affected eye(s) every 4 hours, or 1/2-1 inch ribbon of ointment into conjunctival sac 3-4 times daily. For dermatological use: apply sparingly to affected area 2-3 times daily.
None Documented
None Documented
Oxytetracycline: terminal elimination half-life is 6-10 hours in patients with normal renal function; extends to 48-60 hours in severe renal impairment. Polymyxin B: terminal half-life is 6-8 hours in normal renal function; prolonged to 2-3 days in anuria.
Terramycin: 6-10 hours (prolonged in renal impairment); polymyxin B: 6-7 hours (prolonged in renal impairment); clinical context: dosing interval adjustment required for renal dysfunction
Oxytetracycline: undergoes minimal metabolism; primarily excreted unchanged in urine and feces. Polymyxin B sulfate: not significantly metabolized, excreted mainly unchanged in urine.
Oxytetracycline is primarily excreted unchanged in urine; minimal hepatic metabolism. Polymyxin is not metabolized hepatically; primarily renally excreted.
Approximately 60% of oxytetracycline is excreted unchanged in the urine via glomerular filtration; 20-30% is eliminated in feces via biliary secretion. Polymyxin B is primarily eliminated by renal tubular secretion, with about 60% of a parenteral dose recovered unchanged in urine within 24 hours; minor fecal elimination.
Renal (terramycin: ~70% unchanged in urine; polymyxin B: ~60% unchanged in urine), biliary/fecal (terramycin: ~20-30% in feces; polymyxin B: ~40% fecal elimination)
Oxytetracycline: approximately 20-35% bound to plasma proteins, primarily albumin. Polymyxin B: approximately 50-60% bound to plasma proteins.
Terramycin: ~25-35% bound to plasma proteins (mainly albumin); polymyxin B: ~80-90% bound to plasma proteins (albumin, α-1-acid glycoprotein)
Oxytetracycline: 1.0-1.5 L/kg, indicating extensive tissue distribution, particularly high in liver, kidney, and bone. Polymyxin B: 0.15-0.3 L/kg, reflecting limited distribution mainly to extracellular fluid.
Terramycin: 1.3-1.8 L/kg (distributes widely, including pleural fluid, ascites, bile); polymyxin B: 0.3-0.5 L/kg (limited distribution, primarily extracellular)
Oral oxytetracycline: approximately 60-80% absorbed from the gastrointestinal tract; absorption decreased by food and dairy. Polymyxin B: negligible oral absorption (<1% due to poor gastrointestinal penetration); not administered orally for systemic effect.
Terramycin: oral ~60-80% (food decreases absorption), IM ~70-80%; polymyxin B: not absorbed orally (0.1-0.3%), IM ~100%, IV 100%
For oxytetracycline: CrCl >50 mL/min: usual dose q12h; CrCl 10-50 mL/min: usual dose q18-24h; CrCl <10 mL/min: usual dose q24h or avoid. Polymyxin B: CrCl >30 mL/min: usual dose; CrCl 20-30 mL/min: 1 mg/kg q36h; CrCl 10-20 mL/min: 1 mg/kg q48h; CrCl <10 mL/min: 1 mg/kg q72h or consider alternative.
Terramycin-Polymyxin (oxytetracycline/polymyxin B) is primarily used topically; systemic absorption is minimal. No specific GFR-based dose adjustments required for topical use. For rare systemic use, oxytetracycline requires adjustment if GFR <50 mL/min: prolong dosing interval to every 12-24 hours. Polymyxin B: adjust if GFR <30 mL/min, reduce dose by 50% or increase interval to 12-24 hours.
Oxytetracycline: Avoid in severe hepatic impairment (Child-Pugh C); reduce dose by 50% in moderate (Child-Pugh B) and monitor. Polymyxin B: No specific adjustment but caution in severe hepatic disease.
No specific Child-Pugh based adjustments required for topical use. For systemic oxytetracycline, use with caution in severe hepatic impairment; consider dose reduction or alternative therapy. Polymyxin B is not hepatically metabolized; no adjustment needed.
Oxytetracycline: Contraindicated in children <8 years due to tooth discoloration. For ages >8 years: 25-50 mg/kg/day oxytetracycline IM in divided doses q8-12h. Polymyxin B: 15,000-25,000 units/kg/day IM divided q6-8h.
Children ≥2 years: same as adult dosing for ophthalmic and topical use. For infants <2 years: use only if clearly needed; no specific weight-based dosing established for topical forms.
Use lower end of dosing range for oxytetracycline due to age-related renal decline; monitor renal function. Polymyxin B: Adjust based on renal function; increased risk of nephrotoxicity and neurotoxicity in elderly.
No specific dose adjustments needed for topical ophthalmic or dermatologic use. Use caution with systemic administration due to potential renal impairment; monitor renal function and adjust accordingly.
None.
None
["Prolonged use may result in overgrowth of nonsusceptible organisms including fungi","Sensitivity reactions may occur in patients with known hypersensitivity to tetracyclines or polymyxins","Avoid use in patients with impaired renal function (risk of nephrotoxicity from polymyxin B)"]
["Prolonged use may result in overgrowth of nonsusceptible organisms including fungi.","Photosensitivity reactions may occur with oxytetracycline.","Renal impairment may require dose adjustment for polymyxin.","Avoid use in children under 8 years due to tooth discoloration.","Caution in patients with myasthenia gravis due to potential neuromuscular blockade from polymyxin."]
["Hypersensitivity to oxytetracycline or polymyxin B","Hypersensitivity to any tetracycline","Ocular use in patients with fungal or viral infections"]
["Hypersensitivity to any component","Severe renal impairment (for polymyxin component)","Pregnancy (tetracycline class effects on fetal bone/teeth)","Lactation (tetracycline excreted in milk)"]
Data Pending Review
Data Pending Review
No clinically significant food interactions for ophthalmic use.
Avoid dairy products (milk, cheese, yogurt), antacids, and iron-fortified foods within 2-3 hours of administration. Calcium, magnesium, aluminum, and zinc can chelate tetracyclines, reducing absorption. Do not take with mineral supplements or laxatives containing magnesium.
Tetracyclines cross the placenta. First trimester: minimal risk, but associated with reversible inhibition of fetal bone growth. Second and third trimesters: risk of permanent tooth discoloration (yellow-brown) and enamel hypoplasia; also possible retardation of skeletal development. Polymyxin B has low placental transfer; no known teratogenicity.
Terramycin (oxytetracycline) is a tetracycline antibiotic that crosses the placenta. Tetracyclines are associated with fetal risk, including permanent tooth discoloration and enamel hypoplasia when used during the second and third trimesters. They may also cause skeletal growth retardation and are contraindicated after the first trimester. Polymyxin B sulfate has limited data; animal studies show no teratogenicity but fetal harm cannot be ruled out. Avoid use during pregnancy unless no safer alternative.
Tetracyclines are excreted in breast milk in low concentrations; theoretical risk of dental staining and bone growth inhibition in nursing infants. Polymyxin B is poorly absorbed orally; unlikely to reach systemic circulation in infant. M/P ratio not established. Avoid during breastfeeding if alternative available; if used, monitor infant for diarrhea or candidiasis.
Oxytetracycline is excreted into human breast milk in low concentrations; M/P ratio not established. Theoretical risk of dental discoloration and bone growth suppression in nursing infants, but clinical significance is low due to poor oral absorption of tetracyclines bound to milk calcium. Polymyxin B is excreted in milk in trace amounts; oral absorption is negligible. Use with caution; alternative agents preferred.
No specific dose adjustment recommended in pregnancy; however, due to increased renal clearance, standard doses may be insufficient for severe infections. Avoid use in pregnancy unless absolutely necessary; consider alternative antibiotics.
Pregnancy-induced physiological changes (increased plasma volume, renal clearance) may reduce serum oxytetracycline concentrations; however, dose adjustments are not typically recommended due to risks. Avoid use after first trimester. No specific adjustments for polymyxin B.
Category C
Category C
For ophthalmic use only; avoid prolonged use to prevent fungal or bacterial superinfection. Monitor for hypersensitivity reactions, especially in patients allergic to polymyxins or tetracyclines. Do not use for viral or fungal eye infections.
Terramycin (oxytetracycline) is primarily bacteriostatic, while polymyxin is bactericidal. Monitor renal function in patients receiving polymyxin due to risk of nephrotoxicity. Avoid use in children under 8 years due to tooth discoloration and bone growth inhibition. Caution in patients with myasthenia gravis or porphyria.
Wash hands before and after applying the ointment.Avoid touching the tube tip to the eye or any surface.Apply a thin strip into the conjunctival sac, then close the eye gently.Do not wear contact lenses during treatment.Complete the full course even if symptoms improve.May cause temporary blurred vision; avoid driving until vision clears.
Take on an empty stomach (1 hour before or 2 hours after meals) unless gastrointestinal upset occurs.Avoid dairy products, antacids, iron supplements, and calcium-rich foods within 2-3 hours of dosing.Do not take with magnesium-containing laxatives or bismuth subsalicylate.Complete the full course of therapy even if symptoms improve.Report any signs of superinfection (e.g., oral thrush, vaginal discharge) or persistent diarrhea.Use sunscreen and protective clothing; may cause photosensitivity.Not for use in pregnant women or children under 8 years.Store at room temperature, away from light and moisture.Do not share medication with others.