Olsalazine
Olsalazine is a dimer of **5-aminosalicylic acid (5-ASA)** used primarily for the management of colitis, particularly in patients who are sensitive to sulfasalazine. > **Clinical Warning:** Although the incidence of keratoconjunctivitis sicca (KCS) is much lower than with sulfasalazine, it remains a potential risk. Periodic Schirmer tear tests should be performed during therapy.
Mechanism: Olsalazine is a prodrug that is cleaved by colonic bacteria → releases free **5-ASA** → exerts a local anti-inflammatory effect directly on the colonic mucosa.
Dosing by species
- All uses (Management of colitis) · 10-20 mg/kg · PO · q12h
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Patients sensitive to salicylates
Adverse effects
- Keratoconjunctivitis sicca (dry eye)
Drug interactions
- NSAIDs · Activity will be potentiated by administration of other NSAIDs · moderate
Monitoring
- Schirmer tear tests (periodic)
- Clinical response (resolution of colitis signs)
Overdose
No specific information available. Overdose may exacerbate gastrointestinal signs or increase the risk of salicylate toxicity.
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.