API: Diclofenac Sodium

What Is Diclofenac Sodium and How Does It Work?

Diclofenac Sodium is a nonsteroidal anti-inflammatory drug (NSAID) that is derived from benzene-acetic acid and is used to reduce inflammation and as an analgesic. Diclofenac sodium works by blocking the effect of cyclooxygenase (COX) enzymes. COX enzymes are associated with the production of prostaglandins at the injury site, which cause both pain and inflammation. Blocking COX enzymes decreases prostaglandin production, thereby lowering pain and inflammation. This drug is typically used to treat painful conditions such as rheumatoid arthritis osteoarthritis, and ankylosing spondylitis, as well as sprains and strains, gout, migraine headaches, dental pain, dysmenorrhea, and post-surgery pains. This API is often used in topical preparations such as patches, skin gels, and drops.1

For more information, including a MSDS sheet, please see PNA’s Diclofenac Sodium page.

Approved Indications

Osteoarthritis: Diclofenac sodium in the form of a topical gel is used to relieve pain from osteoarthritis, a type of arthritis caused by a breakdown of lining in the joint. Joints that are typically affected include those in the knee, ankle, foot, elbow, wrist, and hand. Used as a topical liquid, diclofenac sodium can relieve osteoarthritis pain in the knees by reducing muscle contraction in the area.

Rheumatoid Arthritis: Topical preparations of diclofenac sodium also manage symptoms of rheumatoid arthritis, a chronic, autoimmune inflammatory disorder that typically affects the small joints in the hands and feet.

Other Indications: As an NSAID, which is a large class of drugs used to treat non-specific pains, diclofenac sodium is often prescribed for a variety of conditions, such as (but not limited to) ankylosing spondylitis, muscle sprains and strains, gout, migraine headaches (as a treatment but not as a preventive), dental pain, dysmenorrhea, and post-surgery pains.

Side Effects and Drug Interactions

Common side effects in patients taking diclofenac sodium include2:

  • Upset stomach or stomach pain
  • Heartburn
  • Diarrhea, constipation, bloating, or gas
  • Ulcers
  • Dizziness
  • Headaches
  • Anxiety
  • Skin itch or rash
  • Blurred vision
  • Tinnitus

Patients can increase risk of fatal heart attack or stroke, especially used in high doses, long term, or in patients with heart disease.3 Patients who experience stomach or intestinal bleeding, bloody urine, painful urination, trouble maintaining an erection, or irritation in the stomach or bowel should contact their pharmacist or physician immediately.

Patients who are allergic to diclofenac or who have experienced asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs should not take this drug.4

Medications that have potential interactions with diclofenac sodium include lithium, blood pressure medications, methotrexate, some antibiotics, and anticoagulants. Patients who are on antidepressants, steroids, another NSAID, antifungals, blood thinners, or other heart and blood pressure medications should discuss this with their physicians before starting on diclofenac sodium. The effects of this drug on pregnancy and lactation are not well studied.

Latest News and Research

Diclofenac sodium, named for its chemical structure (2-(2,6-dichloranilino) phenylacetic acid), was first synthesized in 1973. There are two forms of diclofenac in use: diclofenac sodium, which has a long course of action, and diclofenac potassium, which is quickly absorbed. Quick absorption is typical preferred where immediate pain relief is needed, whereas the slow absorption of diclofenac sodium is more useful in reducing inflammation. Diclofenac, in general, has been extensively studied and is therefore considered a good first-line NSAID.5

The FDA recently approved the use of diclofenac sodium as a topical gel for treatment of actinic keratosis, a type of skin cancer caused by damage from solar ultraviolet radiation.6 Another study suggests that topical diclofenac sodium, perhaps in conjunction with capsaicin, may be a safe and effective alternative to systemic therapies in patients with chronic, localized musculoskeletal pain or those suffering from neuropathic pain.7

Buying Guide

PNA is a recommended bulk supplier of Diclofenac Sodium and other APIs. You can learn more about Diclofenac Sodium here.

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Show 7 footnotes

  1. “Diclofenac for pain and inflammation,” December 19, 2014, http://patient.info/medicine/diclofenac-for-pain-and-inflammation
  2. “Voltaren Side Effects Center,” April 6, 2015, http://www.rxlist.com/voltaren-side-effects-drug-center.htm
  3. “Diclofenac,” December 1, 2015, http://www.drugs.com/diclofenac.html
  4. “LABEL: DICLOFENAC SODIUM- diclofenac sodium tablet, delayed release DICLOFENAC SODIUM- diclofenac sodium tablet,” https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=1507
  5. “Diclofenac Sodium: A Reappraisal of its Pharmacodynamic and Pharmacokinetic Properties, and Therapeutic Efficacy,” November 11, 2012, http://link.springer.com/article/10.2165/00003495-198835030-00004
  6. “Diclofenac sodium 3% gel for the management of actinic keratosis: 10+ years of cumulative evidence of efficacy and safety,” 2012, http://europepmc.org/abstract/med/22527428
  7. “Topical therapies in the management of chronic pain,” 2013, http://europepmc.org/abstract/med/24547601