Sulfasalazine

AZULFIDINE

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What it isSulfapyridine linked to 5-ASA, split by colonic bacteria; ulcerative colitis and rheumatoid arthritis.

Why this oneIt treats both bowel and joint disease, which is useful in spondyloarthropathy.

What limits itThe sulfapyridine causes most of the toxicity: rash, hemolysis in G6PD deficiency, and reversible oligospermia. Folate supplementation is needed.

FDA-approved for

ulcerative colitis/RA (~1950)

FDA label

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FDA dosing	Population	Start	Target	Max
Ulcerative colitis — initial therapy	Adults	1–2 g/day (to reduce GI intolerance)	3–4 g/day in evenly divided doses (intervals ≤8 h)	>4 g/day increases toxicity risk
Ulcerative colitis — initial therapy	Children ≥6 yr		40–60 mg/kg/day divided into 3–6 doses
Ulcerative colitis — maintenance	Adults		2 g/day
Ulcerative colitis — maintenance	Children ≥6 yr		30 mg/kg/day divided into 4 doses

Renal Give only after critical appraisal in renal damage; discontinue if renal function deteriorates.

Hepatic Give only after critical appraisal in hepatic damage.

Instructions

Take in evenly divided doses, preferably after meals
Maintain adequate fluid intake to prevent crystalluria
May cause orange-yellow discoloration of urine or skin

Contraindications

Intestinal or urinary obstruction
Porphyria
Hypersensitivity to sulfonamides or salicylates

Cautions

Hepatic, renal, and hematologic toxicity (deaths reported)
Serious infections
Oligospermia/infertility (reversible)
Use caution in severe allergy/bronchial asthma
G6PD deficiency (hemolytic anemia)

Adverse reactions

Anorexia
Headache
Nausea
Vomiting
Gastric distress
Reversible oligospermia
Rash

Pregnancy No clear fetal harm in animals; inhibits folic acid absorption (may affect NTD-preventive supplementation).

Lactation Undefined.

NO BOXED WARNINGS

Principal riskHemolysis in G6PD deficiency; reversible oligospermia

Cost, est. cash$5–$150/month

Generic entry1983

Classes and tags

Clinical profile

Therapeutic safety burden1 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

Legacy pregnancy categoryUnknown / historical label unavailable

Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.