🦠 Sulfonamide Antiprotozoal

Albon for Dogs Dosage Calculator

Precise sulfadimethoxine (Albon) loading and maintenance dosing for dogs — covering coccidiosis, susceptible bacterial infections, and treatment duration planning with suspension and tablet formulations.

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Veterinary prescription required. Albon requires adequate hydration throughout therapy — ensure fresh water is always available. Do not use in dogs with sulfonamide hypersensitivity, severe hepatic or renal impairment, or haematological disorders. Monitor for KCS (dry eye) with long-term use.

What Is Albon (Sulfadimethoxine)?

Albon (sulfadimethoxine) is a long-acting sulfonamide antibiotic and antiprotozoal agent that inhibits folate synthesis in susceptible organisms by competitively blocking dihydropteroate synthase (DHPS), preventing the conversion of para-aminobenzoic acid (PABA) to dihydrofolic acid. Dogs cannot synthesise folate independently, but the drug selectively targets microbial DHPS over mammalian cells which obtain folate exogenously.

It is FDA-approved for dogs (and cats) for the treatment of coccidiosis (Isospora canis, I. ohioensis) and susceptible bacterial infections including respiratory, urinary, enteric, and soft tissue infections caused by sulfonamide-sensitive organisms (E. coli, Staphylococcus, Streptococcus, Proteus, Pasteurella, Klebsiella).

Key Pharmacokinetics

  • Oral bioavailability: ~75–90%; well absorbed from GI tract
  • Half-life in dogs: ~13 hours — enables once-daily dosing
  • Protein binding: High (~90%) — displaces other protein-bound drugs
  • Distribution: Penetrates most tissues including CSF (30–50% of plasma levels)
  • Metabolism: Hepatic acetylation and glucuronidation
  • Elimination: Primarily renal; dose reduction required in renal impairment

Dosing Protocol — Critical Details

  • Day 1 Loading Dose: 55 mg/kg PO once — required to achieve rapid therapeutic plasma concentrations
  • Maintenance (Day 2 onward): 27.5 mg/kg PO q24h
  • Coccidiosis treatment duration: Continue for 2 days after clinical signs resolve (typically 5–21 days total)
  • Bacterial infections: Typically 5–14 days; culture and sensitivity guides duration

Available Formulations

  • Oral suspension: 25 mg/mL (125 mg/5 mL)
  • Tablets: 125 mg, 250 mg, 500 mg
  • Bolus (cattle): not for dogs

How to Use This Calculator

  1. Enter your dog’s body weight accurately in kg or lbs
  2. Select the day of treatment — Day 1 uses the loading dose (55 mg/kg); Day 2+ uses maintenance (27.5 mg/kg)
  3. Choose the indication to guide expected treatment duration
  4. Select your available formulation (suspension or tablet strength)
  5. Enter treatment start date to get a complete day-by-day schedule
  6. Click Calculate for dose, volume/tablets per day, and full treatment schedule

🧮 Albon Dose Calculator

Generates full treatment schedule

Albon Dosing Result

Adverse Effects & Monitoring

Adverse Effect Incidence Action
Keratoconjunctivitis sicca (KCS / dry eye) Most significant long-term risk STT baseline before therapy; recheck weekly if >2 weeks
Anorexia, vomiting, diarrhoea Common — give with food Dose with food; discontinue if severe
Crystalluria / urolithiasis Uncommon — ensure hydration Encourage water intake; urinalysis if signs
Bone marrow suppression Rare — prolonged use CBC if therapy >14 days
Hypersensitivity (fever, polyarthritis, facial swelling) Rare but documented Discontinue immediately
Hepatotoxicity Rare ALT/ALP if prolonged therapy

Frequently Asked Questions

Sulfadimethoxine has high protein binding (~90%) and requires a loading dose to rapidly saturate protein-binding sites and achieve therapeutic free drug concentrations in plasma and tissues. Without the higher Day 1 dose, it would take 2–3 days to reach effective levels. The 55 mg/kg loading dose establishes therapeutic concentrations within hours, after which the 27.5 mg/kg maintenance dose maintains them once daily.

Coccidiosis in dogs (caused by Isospora spp.) typically presents as watery to bloody diarrhoea, especially in puppies 3–12 weeks old. Stress, overcrowding, or immunosuppression precipitates clinical disease. Diagnosis is by faecal flotation identifying oocysts. Many adult dogs carry coccidia subclinically — treatment is indicated when clinical signs are present, especially in young puppies or immunocompromised dogs. Retest faeces 1–2 weeks after completing treatment.

Yes — sulfonamides including sulfadimethoxine can cause keratoconjunctivitis sicca (KCS), also known as dry eye. The mechanism involves sulfonamide interference with lacrimal gland acinar cell secretory function. KCS can occur even at therapeutic doses, particularly with treatment courses exceeding 2 weeks. Measure tear production (Schirmer Tear Test, STT) before starting therapy. If STT decreases significantly during treatment, discontinue Albon and start ocular lubricant and/or cyclosporine therapy.

Albon is not a first-line treatment for Giardia. It is FDA-approved for Isospora coccidiosis. Giardia (a flagellate protozoan, not a coccidian) is primarily treated with metronidazole (25 mg/kg q12h × 5–7 days) or fenbendazole (50 mg/kg q24h × 3–5 days). Albon is sometimes used off-label as an adjunct in refractory Giardia cases, but the evidence for efficacy is limited compared to first-line options.

Albon oral suspension (25 mg/mL) should be stored at room temperature (15–25°C/59–77°F) away from direct light. Do not refrigerate (this can cause the suspension to thicken and become difficult to measure accurately). Shake well before each use. Tablets should also be stored at room temperature in a dry place, away from heat and moisture. Check the expiry date — do not use expired sulfonamide products as degradation products can be harmful.

References

  1. Plumb DC. Plumb’s Veterinary Drug Handbook, 9th ed. Wiley-Blackwell; 2018.
  2. Papich MG. Saunders Handbook of Veterinary Drugs, 4th ed. Elsevier; 2016.
  3. Albon (sulfadimethoxine) Prescribing Information. Zoetis Inc.; 2023.
  4. Marks SL, et al. Enteropathogenic bacteria in dogs and cats: diagnosis, epidemiology, treatment, and control. J Vet Intern Med. 2011;25(6):1195-1208.
  • Stogdale L. Sulfonamide-associated side effects in dogs. Can Vet J. 1987;28(9):529-531.