Clofazimine
Also known as: Lamprene · Clofozine · Hansepran · Lamcoin · B-663 · G-30320 · NSC-141046 · Chlofazimine · Clofazimina · Clofaziminum
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Mycobacterium avium complex (MAC) as part of a multi-drug regimen | 4 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| M. avium intracellularae complex infections, leprosy, or opportunistic mycobacteriosis | 4-8 mg/kg PO once a day | PO | q24h | 4 weeks | 🌎 NA |
| Mycobacterial infections | 4-8 mg/kg | PO | q24h | 2-6 months | 🌍 EU |
- Mycobacterium avium complex (MAC) as part of a multi-drug regimen: Other drugs that may be used in combination include doxycycline, clarithromycin, and/or enrofloxacin.
- M. avium intracellularae complex infections, leprosy, or opportunistic mycobacteriosis: Usually as part of a multi-drug protocol.
- Mycobacterial infections: Generally used in combination therapy with other antimicrobials including fluoroquinolones and clarithromycin.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of feline leprosy | 25-50 mg once per day or 50 mg every other day | PO | q24h or q48h | — | 🌎 NA |
| Treatment of localized atypical mycobacterial infections | 8 mg/kg PO once daily | PO | q24h | At least 4 weeks beyond complete clinical resolution | 🌎 NA |
| M. avium intracellularae complex infections, leprosy or opportunistic mycobacteriosis | 4-8 mg/kg PO once a day | PO | q24h | 4 weeks | 🌎 NA |
| Mycobacterial infections (including feline leprosy) | 4-8 mg/kg | PO | q24h | 2-6 months | 🌍 EU |
- Treatment of feline leprosy: Using a regimen of either two or three drugs (with clarithromycin and/or rifampin).
- Treatment of localized atypical mycobacterial infections: Perform wide surgical excision of lesion if possible. Base antibiotic selection on culture and susceptibility results.
- M. avium intracellularae complex infections, leprosy or opportunistic mycobacteriosis: Usually as part of a multi-drug protocol.
- Mycobacterial infections (including feline leprosy): Generally used in combination therapy with other antimicrobials including fluoroquinolones and clarithromycin.
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Avian mycobacteriosis | 6 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| Avian mycobacteriosis (recommended regime for raptors) | 1.5 mg/kg PO q24h | PO | q24h | — | 🌎 NA |
- Avian mycobacteriosis: Protocol 1: with rifampin 45 mg/kg and ethambutol 30 mg/kg.
- Avian mycobacteriosis (recommended regime for raptors): Protocol 2: with ethambutol 20 mg/kg, cycloserine 5 mg/kg, enrofloxacin 15 mg/kg q12h.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Clofazimine is a highly lipophilic, phenazine dye antimycobacterial antibiotic. It is primarily utilized in veterinary medicine as part of a multi-drug regimen for treating leprosy-like syndromes (e.g., feline leprosy, canine leproid granuloma) and Mycobacterium avium complex (MAC) infections.
Clinical Pearls:
- Combination Therapy: Because mycobacteria are notoriously difficult to eradicate and prone to developing resistance, clofazimine is almost never used as a monotherapy.
- Lipophilicity: Its extreme lipophilicity causes it to accumulate heavily in fat and the reticuloendothelial system (macrophages).
- Staining: The drug's nature as a dye leads to its hallmark side effect: profound, long-lasting discoloration of the skin, eyes, and bodily fluids.
- Availability: It can be very difficult for veterinarians to obtain and accurately dose for small animals, often requiring the assistance of a compounding pharmacist.
Mechanism of action
Clofazimine exerts a slowly bactericidal effect against susceptible mycobacteria (M. leprae, M. tuberculosis, M. avium complex, M. bovis, M. chelonei).
- DNA Binding: It binds directly to mycobacterial DNA (preferentially at guanine base sequences) → blocks template function → inhibits DNA replication and cell growth.
- Intracellular Accumulation: It is heavily taken up by macrophages, concentrating the drug exactly where intracellular mycobacteria reside.
- Immunomodulation: Exhibits anti-inflammatory and immunosuppressive properties, likely by inhibiting T-lymphocyte activation and proliferation, though the exact mechanism remains poorly understood.
Safety & warnings
Contraindications
- Use with caution in patients with pre-existing gastrointestinal conditions (diarrhea, abdominal pain)
- Known hypersensitivity to clofazimine
Adverse effects
- Skin, eye, and body fluid discoloration (pink to brownish-black)
- Gastrointestinal pain, nausea, vomiting, diarrhea (dose-limiting)
- Hepatotoxicity (reported in a dog receiving concurrent rifampin)
- Photosensitization (reported in a cat)
- Diarrhoea
- Discoloration of skin, eyes, and body fluids (red-brown/orange)
- Renal impairment
- Hepatic impairment
Precautions
Use with caution in patients with pre-existing gastrointestinal conditions such as diarrhea or abdominal pain. The drug is highly lipophilic and has an extremely long half-life, meaning adverse effects (like skin discoloration) can persist for months to years after discontinuation. It may be difficult to obtain and accurately dose for small animals.
Drug interactions
May reduce clofazimine levels in the skin and increase amounts in plasma and urine; clinical significance is unclear.
May reduce the anti-inflammatory effects of clofazimine; clinical significance is unclear.
Monitoring
- Efficacy against mycobacterial disease
- Adverse effects (primarily gastrointestinal)
- Hepatic function (especially in dogs)
- Hepatic function (ALT, AST, ALP, Bilirubin)
- Renal function (BUN, Creatinine, SDMA)
- Clinical signs of photosensitization
- Gastrointestinal tolerance
Pharmacokinetics
Absorption
Variably absorbed after oral administration (bioavailability 45-70% in humans). Food enhances absorption, but increasing the dosage decreases the percentage absorbed.
Distribution
Highly lipid soluble; distributes primarily to lipid tissue and the reticuloendothelial system. Taken up by macrophages throughout the body. Crosses the placenta and distributes into milk, but does not apparently cross into the CNS or CSF.
Metabolism
Not well defined in veterinary species.
Elimination
Retained in the body for a long period. Bile excretion may be responsible for the majority of excretion, but sputum, sebum, and sweat may also contribute.
Overdose
Very limited data is available. The LD50 for rabbits is 3.3 g/kg and is greater than 5 g/kg in mice, rats, and guinea pigs. Treatment, if required, would include gut emptying and supportive care. Contact an animal poison control center for additional guidance.
Available products
Formulations
- Oral capsules (micronized form in a wax matrix base)
- 100 mg oral capsule
Human-labeled
- Lamprene (restricted availability via Investigational New Drug [IND] protocols only)
- Lamprene 100 mg capsules
Regulatory status
POM (Prescription Only Medicine). Human drug used off-label under the cascade.
POM (Prescription Only Medicine). Human drug used off-label under the cascade.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Clofazimine oral capsules should be stored in tight containers, protected from moisture at temperatures less than 30°C.
Client information
Administration:
- Unless otherwise instructed, give this medication with food to increase absorption and reduce stomach upset.
Important Warnings:
Discoloration: This medication is a dye. It will likely cause your animal's skin to turn color (usually pink, but can range from red to orange to brown). It may also cause discoloring of tears, urine, feces, and other body fluids to a brownish-black color.
- This discoloration is a normal, expected effect of the drug and is not harmful, but it can stain fabrics and may persist for many months after therapy is concluded.
Treatment Duration:
- Treatment for mycobacterial infections is very long (often months). Do not stop the medication early unless directed by your veterinarian, even if your pet seems better.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.