Diclofenac Sodium

What it is and how it works

Mechanism of Action Diclofenac has analgesic, anti-inflammatory, and antipyretic properties. The mechanism of action of diclofenac sodium topical solution, like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2). Diclofenac is a potent inhibitor of prostaglandin synthesis in vitro . Diclofenac concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in animal models. Prostaglandins are mediators of inflammation.

Indications

Diclofenac sodium topical solution is indicated for the treatment of the pain of osteoarthritis of the knee(s). Diclofenac sodium topical solution is a nonsteroidal anti-inflammatory drug indicated for the treatment of the pain of osteoarthritis of the knee(s).

Dosage and administration (summary)

Use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals. The recommended dose is 2 pump actuations on each painful knee, 2 times a day. Apply diclofenac sodium topical solution, to clean, dry skin. Dispense 40 mg (2 pump actuations) directly onto the knee or first into the hand and then onto the knee. Spread evenly around front, back and sides of the knee. Wash hands completely after administering the product. Wait until the area is completely dry before covering with clothing or applying sunscreen, insect repellent, cosmetics, topical medications, or other substances.

Contraindications

Diclofenac sodium topical solution is contraindicated in the following patients: Known hypersensitivity (e.g., anaphylactic reactions and serious skin reactions) to diclofenac or any components of the drug product [ see Warnings and Precautions ( 5.7 , 5.9 ) ] History of asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs.

Warnings and precautions

Hepatotoxicity : Inform patients of warning signs and symptoms of hepatotoxicity. Discontinue if abnormal liver tests persist or worsen or if clinical signs and symptoms of liver disease develop Hypertension : Patients taking some antihypertensive medications may have impaired response to these therapies when taking NSAIDs.Monitor blood pressure ( 5.4 , 7 ) Heart Failure and Edema : Avoid use of diclofenac sodium topical solution in patients with severe heart failure unless benefits are expected to outweigh risk of worsening heart failure Renal Toxicity : Monitor renal function in patients wit…

Pregnancy

Pregnancy Risk Summary Use of NSAIDs, including diclofenac sodium topical solution, can cause premature closure of the fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment.

Storage and supply

Diclofenac sodium topical solution USP, 2% w/w, is supplied as a clear, colorless to faintly pink or orange solution containing 20 mg of diclofenac sodium per gram of solution, in a white polypropylene-dose pump bottle with a clear cap. Each pump actuation delivers 20 mg of diclofenac sodium in 1 gram of solution.

Source: Diclofenac Sodium (Diclofenac Sodium) — US FDA prescribing information, 2025-01-17, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.