Salazopyrin

Action

Unknown. Thought to inhibit prostaglandin synthesis by interfering with secretions in colon and causing local anti-inflammatory action.

Availability

Tablets: 500 mg

Tablets (Azulfidine EN-tabs-delayed-release, enteric-coated): 500 mg

Indications and dosages

➣ Ulcerative colitis

Adults: Initially, 1 to 2 g P.O. daily in equally divided doses q 6 to 8 hours, then 3 to 4 g P.O. daily in equally divided doses q 6 to 8 hours. For maintenance, 500 mg q 6 hours.

Children ages 6 and older: 40 to 60 mg/kg P.O. daily in three to six divided doses. For maintenance, 30 mg/kg P.O. q 6 hours in four divided doses.

➣ Acute rheumatoid arthritis

Adults: Initially, 500 mg to 1 g (delayed-release) P.O. daily for 1 week; then increase by 500 mg/day P.O. q week up to 2 g/day in two divided doses. If no benefit after 12 weeks, increase to 3 g/day given in two divided doses.

➣ Polyarticular-course juvenile rheumatoid arthritis

Children ages 6 and older: 30 to 50 mg/kg P.O. daily in two evenly divided doses. Maximum dosage is 2 g daily.

Off-label uses

• Ankylosing spondylitis

• Crohn's disease

• Psoriatic arthritis

Contraindications

• Hypersensitivity to drug, its metabolites, other sulfonamides, or salicylates

• Porphyria

• Urinary tract or intestinal obstruction

Precautions

Use cautiously in:

• renal or hepatic disease, bronchial asthma, G6PD deficiency, group A beta-hemolytic streptococcal infections, blood dyscrasias

• history of multiple allergies

• pregnant or breastfeeding patients

• children younger than age 2.

Administration

• Give after meals and space doses evenly to reduce GI effects.

• Give with a full glass of water.

• Administer delayed-release tablets whole. Don't let patient crush or chew them.

Adverse reactions

CNS: headache, depression, hallucinations, insomnia, drowsiness, vertigo, fatigue, apathy, anxiety, ataxia, polyneuritis, peripheral neuropathy, seizures

CV: allergic myocarditis or pericarditis

EENT: periorbital edema, optic neuritis, transient myopia, tinnitus

GI: nausea, vomiting, abdominal pain, stomatitis, glossitis, pancreatitis, dry mouth, anorexia, pseudomembranous colitis

GU: hematuria, proteinuria, orange-yellow urine, reversible oligospermia, crystalluria, toxic nephrosis with oliguria and anuria, renal failure

Hematologic: megaloblastic anemia, agranulocytosis, aplastic anemia, thrombocytopenia, leukopenia, hemolytic anemia

Hepatic: jaundice, hepatitis, hepato-cellular necrosis

Respiratory: shortness of breath, pleuritis, cyanosis, allergic pneumonitis, pulmonary infiltrates, fibrosing alveolitis

Skin: generalized skin eruption, urticaria, pruritus, alopecia, local irritation, orange-yellow skin discoloration, exfoliative dermatitis, photosensitivity reaction, erythema multiforme, epidermal necrolysis, Stevens-Johnson syndrome

Other: reversible immunoglobulin suppression, chills, drug fever, hypersensitivity reactions including anaphylaxis, serum sickness, lupuslike syndrome

Interactions

Drug-drug. Digoxin, folic acid: reduced absorption of these drugs

Drug-diagnostic tests. Bilirubin, blood urea nitrogen, creatinine, eosinophils, transaminases: increased levels

Granulocytes, hemoglobin, platelets, white blood cells: decreased levels

Urine glucose test: false-positive result

Drug-food. Folic acid: decreased folic acid absorption

Drug-herbs. Dong quai, St. John's wort: increased risk of photosensitivity

Drug-behaviors. Sun exposure: increased risk of photosensitivity

Patient monitoring

See Monitor CBC with white cell differential. Watch for evidence of blood dyscrasias.

See Stay alert for signs of erythema multiforme. Report early signs before condition can progress to Stevens-Johnson syndrome.

• Monitor patient for signs and symptoms of superinfection, including fever, tachycardia, and chills.

See Monitor liver function tests; watch for signs and symptoms of hepatitis.

See Check kidney function tests weekly. Evaluate patient's fluid intake, urine output, and urine pH. Report hematuria, oliguria, or anuria right away.

• Monitor neurologic status. Report seizures, hallucinations, or depression.

• If patient takes drug for rheumatoid arthritis, monitor therapeutic response 4 to 12 weeks after therapy begins.

Patient teaching

• Tell patient to take on regular schedule as prescribed, along with a full glass of water. Instruct him to drink plenty of fluids to minimize crystal formation in urine.

• Urge patient to complete full course of treatment, even if he feels better after a few days.

See Instruct patient to watch for and immediately report signs and symptoms of hypersensitivity reaction, especially rash.

See Tell patient drug can cause blood disorders, GI and liver problems, serious skin reactions, and other infections. Describe key warning signs and symptoms (easy bruising or bleeding, severe diarrhea, unusual tiredness, yellowing of skin or eyes, sore throat, rash, cough, mouth sores, fever). Instruct him to report these right away.

See Advise patient to promptly report scant or bloody urine or inability to urinate.

• Instruct patient to contact prescriber if he develops depression.

• Teach patient effective ways to counteract photosensitivity effect. Tell him that dong quai and St. John's wort increase phototoxicity risk and should be avoided during therapy.

• Inform patient that drug may discolor skin and body fluids orange-yellow and may permanently stain contact lenses.

• Advise female patient to inform pre-scriber if she is pregnant. Caution her not to take drug near term or when breastfeeding.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.