MESALAMINE

(me-sal'a-meen)

Asacol, Canasa, Lialda, Pentasa, Rowasa, Salofalk

Classifications: antiinflammatory; prostaglandin inhibitor;
Therapeutic: antiinflammatory; prostaglandin inhibitor
Pregnancy Category: B

Availability

250 mg controlled release capsule (Pentasa); 400 mg delayed release tablet (Asacol); 1.2 g delayed release tablet (Lialda); 500 mg suppository, 4 g/60 mL rectal suspension (Rowasa); 500 mg suppositories (Canasa)

Action

Thought to diminish inflammation by blocking cyclooxygenase and inhibiting prostaglandin synthesis in the colon.

Therapeutic Effect

Provides topical antiinflammatory action in the colon of patients with ulcerative colitis.

Uses

Indicated in active mild to moderate distal ulcerative colitis, proctosigmoiditis, or proctitis; maintenance of remission of ulcerative colitis.

Unlabeled Uses

Crohn's disease.

Contraindications

Hypersensitivity to mesalamine, aminosalicylates, or salicylates.

Cautious Use

Renal impairment, renal disease, renal failure, pregnancy (category B), lactation; older adults; sulfite hypersensitivity; sensitivity to sulfasalazine.

Route & Dosage

Ulcerative Colitis
Adult: Rectal (Rowasa) 4 g once/d h.s., enema should be retained for about 8 h if possible or 1 suppository (500 mg) b.i.d.; (Canasa) 500 mg b.i.d., may increase up to 500 mg t.i.d. PO (Asacol) 800 mg t.i.d. times 6 wk; (Pentasa) 500 mg t.i.d. times 6 wk; (Lialda) 2.4 g qd or 4.8 mg qd Maintenance Dose (Asacol) 800 mg b.i.d. or 400 mg q.i.d.
Child: PO 50 mg/kg/d divided q6–12h

Administration

Oral

Ensure that controlled-release and enteric forms of the drug are not crushed or chewed.
Shake the bottle well to make sure the suspension is mixed.

Rectal

Use rectal suspension at bedtime with the objective of retaining it all night.
Store at 15°–30° C (59°–86° F) away from heat and light.

Adverse Effects (≥1%)

CNS: Headache, fatigue, asthenia, malaise, weakness, dizziness. GI: Abdominal pain, cramps, or discomfort, flatulence, nausea, diarrhea, constipation, hemorrhoids, rectal pain, hepatitis (rare). Skin: Sensitivity reactions, rash, pruritus, alopecia. Body as a Whole: Fever. Hematologic: Thrombocytopenia (rare), eosinophilia. Urogenital: Interstitial nephritis.

Interactions

Drug: May decrease the absorption of digoxin.

Pharmacokinetics

Absorption: PR 5–35% absorbed from colon depending on retention time of enema or suppository. PO Asacol, approximately 28% absorbed; 80% of drug is released in colon 12 h after ingestion. PO Pentasa, 50% of drug is released in colon at a pH <6. Peak: 3–6 h. Distribution: Rectal administration may reach as high as the ascending colon. Asacol is released in the ileum and colon; Pentasa is released in the jejunum, ileum, and colon. Low concentrations of mesalamine and higher concentrations of its metabolites are excreted in breast milk. Metabolism: Rapidly acetylated in the liver and colon wall. Elimination: Primarily in feces; absorbed drug excreted in urine. Half-Life: 2–15 h (depending on formulation).

Nursing Implications

Assessment & Drug Effects

Lab tests: Monitor carefully urinalysis, BUN, and creatinine, especially in patients with preexisting kidney disease. The kidney is the major target organ for toxicity.
Assess for S&S of allergic-type reactions (e.g., hives, itching, wheezing, anaphylaxis). Suspension contains a sulfite that may cause reactions in asthmatics and some nonasthmatic persons.
Expect response to therapy within 3–21 d; however, the usual course of therapy is from 3–6 wk depending on symptoms and sigmoidoscopic examinations.

Patient & Family Education

Report to physician promptly: Cramping, abdominal pain, or bloody diarrhea, which are indications for immediate drug withdrawal.
Check with doctor if rectal irritation (e.g., bleeding, blistering, pain, burning, itching) occurs while using this drug.
Check with physician before using any new medicine (prescription or OTC).
Continue medication for full time of treatment even if you are feeling better.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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