PENTASA 500/MG 50/TAB

Indications

Approved Uses

Induction of remission and for the treatment of patients with mildly to moderately active ulcerative colitis.

Dosage & Administration

Dosing by Condition

Ulcerative colitis (active, mild-moderate): 4 g/day in divided doses. Ulcerative colitis (maintenance): not indicated.

Initial Dose

1 g four times daily (4 g/day) for mildly to moderately active ulcerative colitis

Maintenance Dose

1 g four times daily (4 g/day)

Maximum Dose

4 g/day (oral tablets)

Dose Adjustment Notes

Renal: avoid in severe renal impairment and use caution with close monitoring in mild-moderate impairment. Hepatic: use with caution (especially in hepatic impairment) and monitor; no routine titration is required-adjust based on response/tolerability.

How to Take

Swallow the prolonged-release tablets whole with water; do not crush or chew. If swallowing is difficult, the tablets may be dispersed in a small amount of cold water, stirred, and swallowed immediately without chewing the granules/particles.

Side Effects

Common Side Effects

Headache, nausea, abdominal pain, diarrhea, dyspepsia, vomiting, flatulence, rash

Side Effect Frequency

Common (1-10%): diarrhea, headache, nausea, abdominal pain, dyspepsia, vomiting, rash (rates vary by study/formulation; e.g., diarrhea ~3.4%, headache ~2.0%); serious reactions such as interstitial nephritis, myocarditis/pericarditis, pancreatitis, blood dyscrasias are rare/uncommon.

Safety & Warnings

Contraindications

Hypersensitivity to mesalazine/other salicylates/any excipients; severe renal impairment; (often also) severe hepatic impairment-avoid/contraindicated per product labeling.

Warnings & Precautions

Baseline and periodic renal function monitoring; caution in renal/hepatic impairment; stop and evaluate if acute intolerance syndrome occurs; monitor for hypersensitivity (including myocarditis/pericarditis) and blood dyscrasias; be alert for severe cutaneous reactions.

Driving Warning

Safe

Drug Interactions

Drug Interactions

Key clinically relevant interactions: thiopurines (azathioprine/6-MP) ↑ myelosuppression risk; nephrotoxic agents (e.g., NSAIDs) ↑ nephrotoxicity risk; consider additive toxicity with other nephrotoxic drugs and monitor renal function.

Food Interaction

Can be taken with or without food; taking with meals may improve GI tolerability. No clinically important food interaction is expected for Pentasa prolonged-release tablets.

Alcohol Interaction

Safe

Special Populations

Breastfeeding

Caution

Elderly

Use with caution; start at lower end of dosing range; monitor renal function closely as elderly patients are more susceptible to nephrotoxicity

Kidney Impairment

No routine dose adjustment is established; use with caution in any renal impairment with baseline and periodic renal monitoring, and avoid/contraindicated in severe renal impairment; discontinue if renal function deteriorates.

Liver Impairment

Contraindicated in severe hepatic impairment. Use with caution in patients with mild to moderate liver impairment.

Storage & Patient Advice

Missed Dose

Take as soon as remembered; skip if it is almost time for the next dose; do not double the dose

Stopping the Medicine

Do not stop without consulting the prescriber; abrupt discontinuation can precipitate relapse.

Overdose

Symptoms may resemble salicylate toxicity (e.g., nausea/vomiting, tinnitus, hyperventilation, acid-base/electrolyte disturbances); management is supportive with urgent medical evaluation/poison center involvement, and decontamination may be considered if early after ingestion.

Patient Counseling

Swallow tablets whole with water (do not crush/chew); if unable to swallow, disperse in cold water and swallow immediately without chewing particles. Take consistently every day even when well. Maintain adequate hydration and report rash, fever, worsening diarrhea/abdominal pain, or signs of kidney problems; attend scheduled renal (and other) lab monitoring. Urine discoloration with bleach contact can occur and is harmless.

Monitoring Requirements

Baseline and periodic renal function monitoring (serum creatinine/eGFR ± urinalysis) is required; consider baseline and periodic CBC and LFTs, especially if clinically indicated or with concomitant myelotoxic drugs (e.g., thiopurines) or hepatic disease.

Pharmacology

Mechanism of Action

The exact mechanism is not fully defined; mesalazine acts topically in the intestinal mucosa with anti-inflammatory effects, including inhibition of cyclooxygenase and lipoxygenase pathways and reduced prostaglandin/leukotriene production.

Duration of Effect

Prolonged-release provides drug delivery throughout the GI tract over the dosing interval; clinical benefit requires continuous daily dosing to maintain remission.

Half-Life

Mesalazine has a short plasma half-life (about ~0.5-1.5 hours) and N-acetyl-5-ASA about ~5-10 hours; prolonged-release affects absorption profile but does not eliminate the ability to cite these elimination half-lives.

Bioavailability

Approximately 20-30% of an oral dose is systemically absorbed; the remainder acts locally in the gut and is excreted in feces.

Metabolism

Primarily acetylated by N-acetyltransferase in the intestinal mucosa and liver to N-acetyl-5-aminosalicylic acid (Ac-5-ASA); not significantly metabolized by CYP450 enzymes.

Excretion

Unabsorbed drug is excreted in feces; the absorbed fraction is primarily eliminated renally, largely as N-acetyl-5-ASA (and other metabolites).

Protein Binding

Mesalazine: ~43% protein bound; N-acetyl-5-aminosalicylic acid (Ac-5-ASA): ~78% protein bound (often reported up to ~83%).

Product Information

Available Dosage Forms

Controlled-Release Capsules.

Composition per Dose

Each prolonged-release tablet: 500 mg mesalazine (5-aminosalicylic acid)

Generic Availability

Yes

OTC Alternatives

No OTC alternative

Gi Condition

Inflammatory Bowel Disease

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