balsalazide (Rx)

>10%

Headache (15% peds)

Abdominal pain (13% peds )

Vomiting (10% peds)

1-10% (Adults)

Headache (8%)

Abdominal pain (6%)

Nausea (5%)

Diarrhea (5%)

Respiratory infection (4%)

Arthralgia (4%)

Vomiting (4%)

Fatigue (2%)

Insomnia (2%)

Cough (2%)

Pharyngitis (2%)

Rhinitis (2%)

Dyspepsia (2%)

Anorexia (2%)

Flatulence (2%)

Fever (2%)

Constipation (1%)

Cramps (1%)

Ulcerative colitis exacerbation (1%)

Flu like syndrome (1%)

Myalgia (1%)

UTI (1%)

Xerostomia (1%)

1-10% (Pediatrics)

Diarrhea (9%)

Fever (6%)

Ulcerative colitis exacerbation (6%)

Pharyngitis (6%)

Fatigue (4%)

Flu like syndrome (4%)

Nausea (4%)

Hematochezia (4%)

Cough (3%)

Dysmenorrhea (3%)

Stomatitis (3%)

Contraindications

Hypersensitivity to salicylates, balsalazide, mesalamine

Cautions

Sulfasalazine hypersensitivity, coagulation abnormalities, pyloric stenosis, renal/hepatic impairment, allergy, asthma

Risk of exacerbation of ulcerative colitis

Pregnancy Category: B

Lactation: not known whether drug or metabolites are distributed into breast milk, use caution

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Metabolized to mesalamine by intestinal flora

Mesalamine (5-aminosalicylic acid) has anti-inflammatory effect; active component of sulfasalazine, specific MOA unknown; probably inhibits prostaglandin & leukotrienes synthesis & release in colon

Absorption

Bioavailability: Low absorption

Onset: 10 days to 2 wk

Peak plasma time: 1-2 hr

Distribution

Protein bound: 99%

Vd: mesalamine: 0.2 L/kg

Metabolism

Following oral administration, balsalazide passes intact into colon where it is cleaved by intestinal flora to form mesalamine and 4-aminobenzoyl-b-alanine

Mesalamine is rapidly acetylated in colon wall and liver, independent of pt. acetylator status, into N-acetyl-5-aminosalycylic acid

Metabolites: mesalamine (active), N-acetyl-5-aminosalycylic acid (inactive), 4-aminobenzoyl-b-alanine (inactive)

Elimination

Half-life: Undetermined due to large intersubjective variability

Excretion: Feces (as metabolites) >65%; urine (as metabolites) >25%