Voltaren Retard

Active Ingredient & Mechanism of Action

• Active Ingredient: Diclofenac Sodium (in a slow-release dual-matrix tablet).
• Mechanism: It works by non-selectively inhibiting cyclooxygenase (COX-1 and COX-2) enzymes, which suppresses the biosynthesis of prostaglandins—the chemical mediators responsible for joint swelling, localized tissue inflammation, pain, and fever.
• Sustained-Release (Retard) Benefit: Unlike standard immediate-release Voltaren (which releases quickly and requires multiple daily doses), Voltaren Retard releases its active ingredient slowly into the gastrointestinal tract. This provides flat, extended plasma concentrations to control all-day symptoms or morning stiffness.

Available Formulations & Strengths

• Voltaren Retard 75 mg: Prolonged-release film-coated tablets.
• Voltaren Retard 100 mg: High-strength prolonged-release film-coated tablets (most common for single once-daily dosing).

Clinical Indications

• Inflammatory & Degenerative Joint Diseases: Rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis.
• Extra-Articular Rheumatism: Bursitis, tendinitis, tenosynovitis, and frozen shoulder (periarthritis).
• Spinal & Back Syndromes: Low back pain, sciatica, and cervical spine pain.
• Post-Traumatic & Post-Operative Inflammation: Swelling and painful tissue reactions following orthopedic surgery, dental surgery, or soft-tissue trauma.
• Dysmenorrhea: Severe menstrual cramps and pelvic discomfort.

Key Pharmacokinetics

• Absorption: Completely absorbed after oral administration, though the slow release delays peak blood levels compared to immediate-release formulations.
• Synovial Accumulation: Penetrates into synovial fluid (joint fluid) where concentrations remain higher and persist longer than in blood plasma, making it particularly effective for joint diseases.
• Metabolism & Elimination: Metabolized primarily in the liver by the CYP2C9 enzyme. It is eliminated through the kidneys in urine ($\sim 60\%$) and via bile in feces ($\sim 40\%$).

Administration Guidelines

• How to Take:
  • Take with or immediately after a meal alongside a full glass of water to reduce direct gastrointestinal irritation.
  • Swallow whole: Never chew, split, or crush Voltaren Retard tablets. Breaking the sustained-release coating causes a rapid, uncontrolled release of the entire dose at once (dose dumping), significantly increasing stomach toxicity and overdose risks.
• Typical Adult Dosing:
  • Voltaren Retard 100 mg: Taken once daily (often in the evening to relieve overnight joint pain and morning stiffness).
  • Voltaren Retard 75 mg: Taken 1 to 2 times daily depending on the severity of symptoms.
• Maximum Daily Dose Limit: 150 mg in 24 hours.

Safety Profile & Critical Warnings

• Black Box / Major Safety Warnings:
  1. Cardiovascular Risk: Like all systemic NSAIDs, prolonged use or high doses increase the risk of arterial thrombotic events, including heart attack (myocardial infarction) and stroke.
  2. Gastrointestinal Risk: Elevated risk of severe GI adverse events, including stomach ulcers, internal bleeding, and intestinal perforation.
• Common Side Effects: Epigastric pain, nausea, heartburn, flatulence, abdominal cramps, headache, dizziness, and mild skin rashes.
• Contraindications:
  • Active stomach or peptic ulcers, or a history of GI bleeding.
  • Severe heart failure, ischemic heart disease, or peripheral arterial disease.
  • Moderate-to-severe kidney or liver impairment.
  • History of asthma, nasal polyps, or hives triggered by aspirin or other NSAIDs.
  • Pregnancy: Strictly contraindicated starting at 20 weeks of gestation onward (causes premature closure of the fetal ductus arteriosus and lower amniotic fluid).
• Key Drug Interactions:
  • Blood Thinners (e.g., Warfarin, DOACs, Aspirin): Significantly increases gastrointestinal and systemic bleeding risks.
  • Antihypertensives & Diuretics: May reduce the blood-pressure-lowering effects of ACE inhibitors, ARBs, or beta-blockers and increase kidney toxicity.
  • Lithium & Methotrexate: Reduces renal elimination, leading to potentially dangerous accumulations of these drugs in the bloodstream.
  • Other NSAIDs / Steroids: Co-administration with other anti-inflammatories increases stomach ulceration risks without providing additional therapeutic benefit.

Note: Voltaren Retard is a prescription-only sustained-release medication. Dosing duration, gastroprotective co-prescriptions (such as a proton pump inhibitor), and individual cardiovascular or gastrointestinal risk factors should be managed by a licensed healthcare provider.