BALSALAZIDE DISODIUM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BALSALAZIDE DISODIUM (BALSALAZIDE DISODIUM).
Prodrug that delivers mesalamine (5-aminosalicylic acid) to the colon; mesalamine inhibits cyclooxygenase and lipoxygenase pathways, reducing prostaglandin and leukotriene synthesis, and scavenges reactive oxygen species, thereby decreasing colonic inflammation.
| Metabolism | Primarily converted to mesalamine by bacterial azoreductases in the colon; mesalamine is further acetylated by N-acetyltransferase 1 (NAT1) to N-acetyl-5-ASA in the gut and liver. |
| Excretion | Primarily excreted in feces via biliary elimination (approximately 90%) following conversion to mesalamine; renal excretion accounts for less than 10% of the dose as mesalamine and its metabolites. |
| Half-life | Balsalazide itself has a terminal elimination half-life of approximately 0.5–1 hour; the active moiety mesalamine has a terminal half-life of 5–10 hours, which may be prolonged in renal impairment. |
| Protein binding | Mesalamine is approximately 40–45% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | The apparent volume of distribution for mesalamine is about 0.5 L/kg, indicating distribution primarily into extracellular fluid. |
| Bioavailability | Oral bioavailability of balsalazide is approximately 0.3% for the parent drug; almost all of the dose is converted to mesalamine in the colon, with systemic absorption of mesalamine about 20–30% of the released dose. |
| Onset of Action | Oral administration: clinical response may be seen within 3–21 days, though full therapeutic effect often requires 2–4 weeks of continuous therapy. |
| Duration of Action | Duration of action is related to mesalamine's presence in the colonic lumen; typically dosed three times daily for maintenance of remission. Clinical effects persist as long as the drug is taken regularly. |
2.25 g (three 750 mg capsules) orally three times daily
| Dosage form | CAPSULE |
| Renal impairment | Contraindicated in patients with severe renal impairment (eGFR <30 mL/min/1.73 m²). For moderate impairment (eGFR 30-59 mL/min), use with caution and monitor renal function; no specific dose adjustment recommended. No adjustment for mild impairment (eGFR ≥60 mL/min). |
| Liver impairment | No specific dose adjustments recommended based on Child-Pugh classification. Caution in severe hepatic impairment due to limited data. |
| Pediatric use | Not approved for use in pediatric patients (safety and efficacy not established). |
| Geriatric use | No specific dose adjustment required. Use with caution due to potential for age-related renal impairment; monitor renal function periodically. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BALSALAZIDE DISODIUM (BALSALAZIDE DISODIUM).
| Breastfeeding | Balsalazide is a prodrug; mesalamine is excreted into breast milk in low concentrations. The milk-to-plasma ratio for mesalamine is approximately 0.4. No adverse effects reported in breastfed infants. Caution with diarrhea in infant. Consider benefit over risk. |
| Teratogenic Risk | Balsalazide disodium is a prodrug of mesalamine. In animal studies, no teratogenic effects were observed at doses up to 2.4 g/kg/day in rats and rabbits. Human data on balsalazide are limited, but mesalamine exposure is considered low risk. No increased risk of major congenital malformations reported. First trimester: low risk, no specific teratogenicity. Second and third trimesters: no known fetal harm. Avoid if possible due to limited data. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to balsalazide, mesalamine, salicylates, or any component of the formulation"]
| Precautions | ["Renal impairment (potential for nephrotoxicity, monitor renal function)","Gastric outlet obstruction or esophageal stricture (delayed release may be obstructed)","Exacerbation of ulcerative colitis (rare)","Hypersensitivity reactions (e.g., pericarditis, pancreatitis)"] |
| Food/Dietary | No specific food restrictions. However, high-fat meals may slightly delay absorption; take consistently with or without meals. Avoid alcohol as it may exacerbate gastrointestinal side effects. |
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| Fetal Monitoring | Monitor for maternal gastrointestinal side effects (nausea, diarrhea). No specific fetal monitoring required. In late pregnancy, monitor for potential neonatal diarrhea if used near term. |
| Fertility Effects | No studies on fertility effects in humans. Animal studies show no impairment of fertility at doses up to 2.4 g/kg/day. Unlikely to affect fertility. |
| Clinical Pearls |
| Balsalazide is a prodrug of mesalamine (5-ASA) activated by colonic bacteria; ensure intact colon for efficacy. May cause rare but severe idiosyncratic reactions including pancreatitis, hepatitis, and blood dyscrasias. Monitor renal function (interstitial nephritis risk) and CBC periodically. Avoid in patients with salicylate hypersensitivity. |
| Patient Advice | Take capsules whole with or without food; do not crush or chew. · Drink plenty of fluids to prevent kidney stones. · Stop drug and contact your doctor if you experience severe abdominal pain, bloody diarrhea, fever, rash, or yellowing of skin/eyes. · May cause harmless orange-red discoloration of urine (due to metabolites) – this is normal. · Avoid concurrent NSAIDs unless cleared by provider due to increased nephrotoxicity risk. |