Introduction
Rowasa (mesalamine) is an anti-inflammatory medication used primarily in the management of inflammatory bowel diseases. It belongs to the class of aminosalicylates and is specifically formulated for rectal administration. Rowasa is available as a rectal suspension enema that delivers the active drug directly to the colonic mucosa, making it particularly effective for distal colonic disease.
Mechanism of Action
Mesalamine (5-aminosalicylic acid) acts locally in the colon to exert its anti-inflammatory effects through multiple mechanisms. The drug inhibits cyclooxygenase and lipoxygenase pathways, reducing prostaglandin and leukotriene production. It also scavenges reactive oxygen species, inhibits cytokine production (particularly IL-1 and TNF-α), and interferes with neutrophil chemotaxis and activation. The exact mechanism by which mesalamine induces and maintains remission in ulcerative colitis is not fully understood, but it appears to modulate the inflammatory response in the colonic mucosa without significant systemic immunosuppression.
Indications
Rowasa is indicated for:
- Treatment of active mild to moderate distal ulcerative colitis, proctosigmoiditis, or proctitis
- Maintenance of remission in ulcerative colitis
Dosage and Administration
Active disease: 60 mL (4 g) rectal suspension once daily, preferably at bedtime, retained for approximately 8 hours Maintenance therapy: 60 mL (4 g) rectal suspension every other day or every third day Administration: Shake bottle well before use. Remove protective sheath and gently insert applicator tip into rectum. Squeeze bottle to deliver contents. Remain recumbent for at least 30 minutes after administration to promote retention. Special populations:- Renal impairment: Use with caution in patients with renal impairment
- Hepatic impairment: No dosage adjustment required
- Elderly: No specific dosage adjustment required
- Pediatrics: Safety and effectiveness not established
Pharmacokinetics
Absorption: Minimal systemic absorption (10-30%) following rectal administration Distribution: Primarily local action in colorectal mucosa; low plasma protein binding (40-50%) Metabolism: Extensive acetylation in colonic mucosa and liver; primarily by N-acetyltransferase 1 (NAT1) Elimination: Renal excretion of acetylated metabolite (half-life: 12 hours); fecal excretion of unabsorbed drugContraindications
- Hypersensitivity to mesalamine, salicylates, or any component of the formulation
- History of hypersensitivity to sulfasalazine
- Severe renal impairment (GFR <30 mL/min)
Warnings and Precautions
- Renal toxicity: Monitor renal function at baseline and periodically during therapy
- Acute intolerance syndrome: May mimic exacerbation of IBD (cramping, abdominal pain, bloody diarrhea)
- Mesalamine-induced cardiac hypersensitivity: Rare reports of myocarditis and pericarditis
- Pulmonary toxicity: Interstitial lung disease reported rarely
- Hepatic effects: Monitor liver enzymes; rare reports of hepatitis
- Sun sensitivity: Photosensitivity reactions reported
Drug Interactions
- Anticoagulants: Potential increased risk of bleeding (theoretical)
- Nonsteroidal anti-inflammatory drugs: May diminish therapeutic effect of mesalamine
- Thiopurines (azathioprine, mercaptopurine): Potential increased risk of blood disorders
- Lactobacillus and other probiotics: Theoretical interaction with antibiotic components
Adverse Effects
Common (≥1%):- Headache (15%)
- Abdominal pain/cramps (8%)
- Flatulence (6%)
- Nausea (5%)
- Rectal pain (4%)
- Fever (3%)
- Rash (2%)
- Dizziness (2%)
- Acute renal failure
- Pancreatitis
- Pericarditis
- Myocarditis
- Hepatitis
- Blood dyscrasias (agranulocytosis, aplastic anemia)
- Pulmonary fibrosis
- Stevens-Johnson syndrome
Monitoring Parameters
- Clinical response: Symptom improvement in active disease; maintenance of remission
- Renal function: Serum creatinine at baseline and every 3-6 months during therapy
- Complete blood count: Baseline and periodic monitoring
- Liver function tests: Baseline and periodic monitoring
- Urinalysis: Periodic assessment for proteinuria
- Tolerance: Assess for signs of acute intolerance syndrome
Patient Education
- Administer at bedtime for optimal retention
- Shake bottle well before use
- Remain recumbent for at least 30 minutes after administration
- Report any fever, rash, chest pain, difficulty breathing, or unusual bleeding/bruising
- Regular follow-up with healthcare provider for monitoring
- Store at room temperature (do not refrigerate)
- Discard any unused medication after 14 days of opening
- Report worsening abdominal symptoms or blood in stool
- Use sun protection due to potential photosensitivity
References
1. Sandborn WJ, Hanauer SB. Systematic review: the pharmacokinetic profiles of oral mesalazine formulations and mesalazine pro-drugs used in the management of ulcerative colitis. Aliment Pharmacol Ther. 2003;17(1):29-42. 2. Kornbluth A, Sachar DB; Practice Parameters Committee of the American College of Gastroenterology. Ulcerative colitis practice guidelines in adults: American College of Gastroenterology, Practice Parameters Committee. Am J Gastroenterol. 2010;105(3):501-523. 3. Ford AC, Achkar JP, Khan KJ, et al. Efficacy of 5-aminosalicylates in ulcerative colitis: systematic review and meta-analysis. Am J Gastroenterol. 2011;106(4):601-616. 4. Package Insert: Rowasa (mesalamine) rectal suspension. Allergan, Inc.; 2021. 5. Lichtenstein GR, Hanauer SB, Sandborn WJ; Practice Parameters Committee of American College of Gastroenterology. Management of Crohn's disease in adults. Am J Gastroenterol. 2009;104(2):465-483. 6. Raine T, Bonovas S, Burisch J, et al. ECCO Guidelines on Therapeutics in Ulcerative Colitis: Medical Treatment. J Crohns Colitis. 2022;16(1):2-17.