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# Diclofenac (Tablet)
## Overview
Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis. It provides analgesic, anti-inflammatory, and antipyretic effects.
## Primary Indications
* Osteoarthritis
* Rheumatoid arthritis
* Ankylosing spondylitis
* Management of acute pain (short-term)
* Primary dysmenorrhea
## Adult Dosing
* **Osteoarthritis:** 50 mg BID to TID or 75 mg BID.
* **Rheumatoid Arthritis:** 50 mg TID to QID or 75 mg BID.
* **Ankylosing Spondylitis:** 25 mg QID, with an additional 25 mg at bedtime if needed (max 125 mg/day).
* **Maximum Dose:** Generally 150 mg/day for chronic use. Immediate-release tablets are not interchangeable with extended-release formulations.
## Pediatric Dosing
* **Safety/Efficacy:** Well-established FDA-labeled dosing for pediatric oral tablets is limited. Juvenile idiopathic arthritis (JIA) dosing is often cited in literature as 2–3 mg/kg/day divided into 2–4 doses.
* **Note:** Always consult specialized pediatric dosing references (e.g., Harriet Lane) or local institutional protocols before prescribing for patients under 18.
## Dose Adjustments
* **Renal Impairment:** Avoid in severe renal impairment (CrCl <30 mL/min). Use with caution in mild-to-moderate impairment.
* **Hepatic Impairment:** Use with extreme caution. Discontinue if liver test abnormalities persist or worsen.
## Contraindications
* Known hypersensitivity to diclofenac or aspirin/other NSAIDs (potential cross-reactivity).
* History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
* Setting of coronary artery bypass graft (CABG) surgery.
* Active peptic ulcer disease or GI bleeding.
* Severe heart failure (NYHA Class II-IV).
## Adverse Effects
* **GI:** Dyspepsia, nausea, abdominal pain, increased risk of gastric ulceration/perforation.
* **Cardiovascular:** Increased risk of myocardial infarction and stroke (black box warning).
* **Renal/Hepatic:** Elevated liver enzymes (transaminases), acute kidney injury, fluid retention/edema, hypertension.
## Key Drug Interactions
* **Anticoagulants (Warfarin):** Increases risk of bleeding.
* **SSRIs/SNRIs:** Increases risk of GI bleeding.
* **ACE Inhibitors/ARBs/Diuretics:** Decreased antihypertensive efficacy and increased risk of nephrotoxicity.
* **Lithium/Methotrexate:** Increases plasma concentrations and potential toxicity of these drugs.
## Monitoring
* **Baseline:** CBC, LFTs, and baseline serum creatinine/BUN.
* **Ongoing:** Monitor blood pressure, signs of GI bleed, and periodically reassess renal function and LFTs in long-term therapy.
## Clinical Pearls
* Take with food to minimize GI distress.
* Use the lowest effective dose for the shortest duration necessary.
* Diclofenac has a higher incidence of transaminase elevations compared to other NSAIDs; monitor LFTs within 4–8 weeks of initiation.
* Not indicated for the treatment of perioperative pain in the setting of coronary artery bypass graft (CABG) surgery.
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**Disclaimer:** This information is for educational purposes only. Drug dosing, contraindications, and interaction profiles can change. Always consult the most current official prescribing information (package insert) or institutional pharmacy protocols before making clinical decisions.
