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# Tab Diclofenac
## Overview
Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) with potent analgesic, anti-inflammatory, and antipyretic properties. It acts primarily by inhibiting cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis. Available as immediate-release (IR) tablets, delayed-release (DR) tablets, and extended-release (ER) tablets.
## Primary Indications
* Osteoarthritis
* Rheumatoid arthritis
* Ankylosing spondylitis
* Management of mild-to-moderate pain or primary dysmenorrhea
## Adult Dosing
* **Osteoarthritis:** 100–150 mg/day in divided doses (e.g., 50 mg BID or TID; 75 mg BID).
* **Rheumatoid arthritis:** 150–200 mg/day in divided doses (e.g., 50 mg TID or QID).
* **Ankylosing spondylitis:** 100–125 mg/day (25 mg QID plus an extra 25 mg at bedtime if needed).
* **Extended-Release (ER):** 100 mg once daily.
* **Maximum Dose:** Generally 150–200 mg/day depending on the specific formulation; adhere strictly to the product-specific labeling.
## Pediatric Dosing
Safety and efficacy have not been established in children. Use in pediatric populations is off-label and generally avoided in favor of ibuprofen or naproxen.
## Dose Adjustments
* **Renal Impairment:** Avoid in severe renal impairment (CrCl <30 mL/min). Use with caution in moderate impairment.
* **Hepatic Impairment:** Reduce dose or avoid in severe hepatic impairment. Monitor liver enzymes (ALT/AST) periodically.
* **Geriatric:** Start at the lowest effective dose; increased risk of GI bleeding and cardiovascular events.
## Contraindications
* Known hypersensitivity to diclofenac or other NSAIDs (including aspirin-induced asthma/urticaria).
* History of GI bleeding or perforation related to previous NSAID therapy.
* Active peptic ulcer disease or inflammatory bowel disease.
* Coronary artery bypass graft (CABG) surgery (perioperative pain management).
* Severe heart failure or severe renal impairment.
* Third trimester of pregnancy (risk of premature closure of ductus arteriosus).
## Adverse Effects
* **GI:** Dyspepsia, nausea, abdominal pain, increased risk of GI ulceration/bleeding.
* **CV:** Increased risk of thrombotic events (myocardial infarction, stroke), hypertension, fluid retention/edema.
* **Hepatic:** Elevated transaminases; rare but serious hepatotoxicity.
* **Renal:** Acute kidney injury, interstitial nephritis, hyperkalemia.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of major bleeding.
* **Antiplatelets/SSRIs:** Increased risk of GI bleeding.
* **ACE Inhibitors/ARBs/Diuretics:** Reduced antihypertensive effect; increased risk of nephrotoxicity.
* **Lithium/Methotrexate:** Diclofenac may decrease renal clearance, leading to elevated toxic levels.
## Monitoring
* **Baseline/Intermittent:** CBC, serum creatinine, BUN, and electrolytes (if prolonged use).
* **Hepatic:** Monitor ALT/AST within the first 4–8 weeks of therapy and periodically thereafter.
* **Clinical:** Monitor for signs of GI bleeding, changes in blood pressure, and development of peripheral edema.
## Clinical Pearls
* **Administration:** Take with food or milk to minimize GI upset. DR tablets should be swallowed whole; do not crush or chew.
* **CV Risk:** Use the lowest effective dose for the shortest duration necessary to control symptoms.
* **Formulation Warning:** Different salt forms (e.g., diclofenac potassium vs. sodium) are not always milligram-equivalent for all indications. Always verify the specific brand/generic label.
* **Counseling:** Advise patients to avoid taking concomitant over-the-counter NSAIDs (eg, ibuprofen) to prevent overdose and excessive side effects.
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**Educational Disclaimer:** This information is for educational purposes only. Always consult current institutional prescribing protocols, product-specific package inserts, and clinical databases (e.g., Lexicomp, UpToDate) before prescribing or administering medication.
