Olfen SR

Olfen SR (Sustained Release) is a brand-name nonsteroidal anti-inflammatory drug (NSAID) manufactured by Mepha / Acino. It contains Diclofenac Sodium as its active ingredient in a prolonged-release formulation designed to provide extended pain and inflammation relief over 12 to 24 hours.

Active Ingredient & Mechanism of Action

• Active Ingredient: Diclofenac Sodium (in extended/sustained-release pellets or matrix).

• Mechanism: Inhibits cyclooxygenase (COX-1 and COX-2) enzymes, blocking the biosynthesis of prostaglandins—the primary chemical mediators responsible for localized pain, swelling, fever, and joint inflammation.

• SR Advantage: The sustained-release formulation releases the active drug gradually into the gastrointestinal tract, maintaining steady therapeutic blood levels and allowing once- or twice-daily dosing.

Available Dosage Forms & Strengths

Olfen SR is available in solid oral sustained-release formulations:

• Olfen 75 SR: 75 mg prolonged-release depot tablets or capsules.

• Olfen 100 SR: 100 mg prolonged-release depot capsules (Depocaps).

Clinical Indications

Olfen SR is prescribed for long-term or acute management of painful and inflammatory conditions:

• Arthritic & Joint Disorders: Rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis.

• Musculoskeletal & Soft Tissue Pain: Acute backache, frozen shoulder, bursitis, tendinitis, tenosynovitis, and sprains/strains.

• Gout & Trauma: Acute gout flares, post-traumatic or post-surgical inflammation and swelling, and fractures.

• Dysmenorrhea: Severe menstrual cramps.

Key Pharmacokinetics

• Absorption: Gradually absorbed throughout the digestive tract to provide extended therapeutic coverage. Peak plasma concentrations are reached more slowly compared to immediate-release diclofenac, avoiding sharp drug spikes.

• Distribution: Accumulates and persists in joint synovial fluid at higher concentrations than in blood plasma over extended periods.

• Metabolism & Elimination: Metabolized by the liver (primarily CYP2C9) and excreted predominantly through the kidneys in urine and via bile/feces.

Administration Guidelines

• How to Take:

  • Take with or immediately after a meal with a full glass of water to minimize stomach discomfort.

  • Swallow whole: Do not chew, crush, split, or open the sustained-release capsules/tablets, as damaging the coating destroys the extended-release mechanism and increases the risk of side effects or overdose.

• Typical Adult Dosing:

  • 100 mg SR once daily (often taken in the evening to relieve nocturnal pain and morning stiffness).

  • Or 75 mg SR 1 to 2 times daily depending on clinical severity.

• Maximum Daily Dose Limit: 150 mg per 24 hours.

Safety Profile & Critical Warnings

• Black Box / Serious Safety Warnings:

  1. Cardiovascular Risk: Like all NSAIDs, prolonged use or high doses increase the risk of serious cardiovascular thrombotic events, heart attack, and stroke.

  2. Gastrointestinal Risk: Can cause stomach ulcers, internal bleeding, and intestinal perforation.

• Common Side Effects: Nausea, indigestion, epigastric pain, flatulence, diarrhea, headache, dizziness, and mild skin rash.

• Contraindications:

  • Active peptic/gastric ulcers or history of gastrointestinal bleeding.

  • Severe heart failure, established ischemic heart disease, or severe liver/kidney failure.

  • History of asthma, hives, or acute allergic reactions triggered by aspirin or other NSAIDs.

  • Pregnancy: Contraindicated starting at 20 weeks of gestation (risk of premature closure of the fetal ductus arteriosus and low amniotic fluid).

• Key Drug Interactions:

  • Blood Thinners (e.g., Warfarin, Aspirin): Significantly increases GI and systemic bleeding risk.

  • Antihypertensives & Diuretics: Can diminish blood-pressure-lowering effects and increase risk of kidney injury.

  • Other NSAIDs / Steroids: Co-administration increases risk of gastric ulceration without additional benefit.

  • Lithium & Methotrexate: Inhibits renal clearance, raising toxic blood levels of these drugs.

Note: Olfen SR is a prescription-only sustained-release medication. Dosing duration, gastroprotective needs (such as taking a proton pump inhibitor alongside it), and individual cardiovascular or renal risks should be supervised by a healthcare professional.