Mesalamine (5-aminosalicylic acid, 5-ASA)

 Action Reduces inflammation of colon topically by preventing production of substances involved in inflammatory process such as arachidonic acid.

 Indications Treatment of active, mild to moderate distal ulcerative colitis, proctosigmoiditis or proctitis. Unlabeled use(s): Treatment of Crohn's disease.

 Contraindications Hypersensitivity to salicylates.

 Route/Dosage

ADULTS: CONTROLLED RELEASE TABLETS OR CAPSULES: PO 800 mg tid for total of 2.4 g/day for 6 wk. SUPPOSITORIES: PR 500 mg suppository bid for up to 6 wk. Retain suppository in rectum for 1–3 hr or more to achieve maximum benefit. SUSPENSION ENEMA: PR 4 g in 60 ml as rectal instillation q day for up to 6 wk, preferably at bedtime, retained for 8 hr.

 Interactions None well documented.

 Lab Test Interferences May cause transient asymptomatic elevations in liver function test results AST, ALT, alkaline phosphatase) and serum creatinine. Hepatitis is rare.

 Adverse Reactions

CV: Chest pain. CNS: Headache; asthenia; chills; dizziness; fever; sweating; malaise. DERM: Acne; itching; rash. EENT: Rhinitis; sore throat; pharyngitis. GI: Abdominal pain; cramps; discomfort; colitis exacerbation; constipation; iarrhea; dyspepsia; vomiting; flatulence; nausea; eructation; rectal pain; oreness; burning. RESP: Cough. OTHER: Arthralgia; back pain; hypertonia; myalgia; dysmenorrhea; edema; flu syndrome; pain.

 Precautions

Pregnancy: Category B. Lactation: Excreted in breast milk. Children: Safety and efficacy not established. Intolerance and colitis exacerbation: Some patients develop acute intolerance syndrome or exacerbation of colitis characterized by cramping, acute abdominal pain and bloody diarrhea, and occasionally fever, headache, malaise, pruritus, conjunctivitis and rash. Symptoms generally abate when mesalamine is discontinued. Pericarditis: Rarely, pericarditis has been reported. Observe for chest pain or dyspnea. Pyloric stenosis: Gastric retention of oral mesalamine may occur in patients with pyloric stenosis. Renal impairment: Patients with history of renal disease or dysfunction may have worsening of renal function. Sulfite sensitivity: Some products may contain sulfites, which may cause allergic reactions in susceptible individuals.

 Administration/Storage

• Instruct patient to swallow tablets or capsules whole.
• Do not alter form of medication prior to administration.
• Shake suspension well and position patient in knee-chest position or on left side with lower leg extended and upper right leg flexed for administration.
• Be certain that suppositories are retained for 1–3 hr and enemas retained for about 8 hr (preferably at bedtime) to achieve maximum effectiveness.
• Full course of therapy may last up to 6 wk and patient response may occur within 3–12 days.
• Store at room temperature.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Monitor results of renal function tests throughout therapy.
• Assess for increased abdominal pain, nausea, diarrhea and vomiting and notify physician of any problems.
• Document character and frequency of stools.

 Patient/Family Education

• Tell patient to swallow capsules or tablets whole. Explain that outer coating must be intact to pass through stomach and travel to sigmoid colon.
• Tell patient to notify physician if any remnant of capsule or tablet is seen in stool.
• Tell patient to retain suppository 1–3 hr or to retain enema for 8 hr.
• Teach patient proper positioning and technique for self-administering enema. Include knee-chest and left side positions to promote medication advancement to sigmoid colon.
• Tell patient to report these symptoms to physician: increase in abdominal pain, diarrhea or vomiting.
• Instruct patient to notify physician of hives, itching, wheezing, rash or fever.