- Generic name: Diclofenac Potassium; Diclofenac Sodium
- Brand names: Voltaren®, Cataflam®, Arthrotec® (in combination with misoprostol)
- Pharmacologic category: Nonsteroidal Anti-inflammatory Drug
- FDA approved: July 28, 1988
- Pregnancy risk factor: B (topical); C (oral)/D (3rd trimester)
Medical uses
Diclofenac is a relatively strong non-steroidal anti-inflammatory drug (NSAID) of the arylalkanoic acid family. This medicine has analgesic, anti-inflammatory, and antipyretic properties.
Diclofenac has a wide application in painful conditions. It is very effective in cases of moderate to severe pain where quick pain relief is required. Diclofenac is used to reduce inflammation and pain in the following conditions:
- Ankylosing spondylitis
- Menstrual pain (Primary dysmenorrhea)
- Rheumatoid arthritis
- Osteoarthritis
- Gout attacks
- Mild to moderate post-operative or post-traumatic pain
- Pain caused by kidney stones and gallstones
Ophthalmic solution is indicated for pain relief or decrease of inflammation after cataract or corenal surgery.
In the United States all diclofenac (Voltaren) formulations are classified as Rx-only.
In several countries diclofenac is available over-the-counter (OTC). OTC preparations are licensed in New Zealand, Australia, Sweden, Switzerland, Germany, South Africa.
Diclofenac for Acute gouty arthritis
Gout is a recurrent inflammatory disorder caused by high blood levels of uric acid (hyperuricemia). Painful symptoms in gout result from deposition of uric acid crystals in joints. Diclofenac is used to relieve symptoms of an acute gouty attack 4. Benefits are provided by diclofenac ability to suppress inflammation.
Dosage for Acute gout attack: 50 mg 3 times daily for 3 to 6 days.
Diclofenac for Back pain
NSAIDs are frequently prescribed for the symptomatic management of low back pain due to their analgesic and their anti-inflammatory action. Diclofenac reduces from mild to very severe low back pain8-9.
Dosage for Back pain: 50 mg 3 times daily or 75 mg twice daily7.
Diclofenac for Tendonitis, Bursitis
Bursitis and tendinitis are soft tissue rheumatic syndromes.
Tendonitis (also called tendinitis) is an inflammation of the tendon which attaches a muscle to a bone.
Bursitis is an inflammation of bursa, a fluid-filled sac near a joint.
Diclofenac is effective for short term treatment of acute pain associated with tendinitis6 or bursitis5.
Dosage for Tendonitis, Bursitis: 50 mg 2-3 times daily for 7-14 days5. Diclofenac in not recommended for long-term treatment of chronic conditions.
Pharmacological characteristics
- Duration of action: The duration of action of one single dose is much longer (6 to 8 hours) than the very short half-life of the drug indicates. This could partly be due to a particular high concentration achieved in synovial fluids.
- Onset of action: Potassium salt (Cataflam) is more rapid than sodium salt (Voltaren) because it dissolves in the stomach instead of the duodenum.
- Bioavailability: 55%
- Metabolism: Hepatic to several metabolites
- Elimination half-life: 2 hours
- Excretion: Urine (65%); feces (35%)
Benefits
- Diclofenac is among the better tolerated NSAIDs.
- Rather potent pain reliever.
- May alleviate the discomfort associated with inflammatory infections of the throat, ear, or nose.
- Availability of diverse formulations (tablets, suppository, gel, transdermal patch, injection).
- Compared to opioids diclofenac does not cause respiratory depression, sedation, and constipation.
Risks & Disadvantages
- Hypersensitivity (anaphylactoid) reactions. Even in patients without prior exposure anaphylactoid reactions may occur.
- Cardiovascular side effects. May cause cardiovascular problems, including heart attack, stroke, and new onset or worsening of preexisting hypertension.
- Gastrointestinal side effects. Long-term use of diclofenac and similar NSAIDs predisposes for peptic ulcers. It can cause gastrointestinal bleeding, ulceration, and perforation of the stomach, small intestine, or large intestine. These serious problems can occur at any time, and often without warning signs or symptoms.
- Liver effects. Diclofenac is commonly associated with elevation of aminotransferase, generally during first 4-6 months of therapy 2.
Off-label treatment
- Alzheimer's disease. Diclofenac may prevent the development of Alzheimer's disease if given daily in small doses during many years. All investigations were stopped after it was found that some of the other investigated NSAIDs (naproxen, rofecoxib) caused a higher incidence of death cases due to cardiovascular side effects and stroke compared to placebo.
- Shy-Drager syndrome. Diclofenac has been found to increase the blood pressure in patients with Shy-Drager syndrome (autonomous hypotension) often seen in diabetic patients. Currently, this use is highly investigational and cannot be recommended as routine treatment.
- E. coli urinary tract infections 3.
Mode of action
Inhibits prostaglandin synthesis by decreasing the activity of the enzyme, cyclooxygenase, which results in decreased formation of prostaglandin precursors. Mechanism of action for the treatment of AK has not been established.
Diclofenac is a unique NSAIDs in that it has 3 mechanisms of action:
1. Inhibition of the arachidonic acid COX system (3 to 1,000 time more potent than other NSAIDs on a molar basis), resulting in a decreased production of prostaglandins and thromboxanes; diclofenac inhibits COX-2 preferentially more than COX-1, however, it is not as selective as celecoxib;
2. Inhibition of the lipoxygenase pathway, resulting in decreased production of leukotrienes, particularly the proinflammatory LKB4;
3. Inhibition of arachidonic acid release and stimulation of its reuptake, resulting in a reduction of arachidonic acid availability.
References
- 1. U.S. FDA. Diclofenac Prescribing Information (PDF format)
- 2. Laine L, Goldkind L, Curtis SP, Connors LG, Yanqiong Z, Cannon CP. How common is diclofenac-associated liver injury? Analysis of 17,289 arthritis patients in a long-term prospective clinical trial. Am J Gastroenterol. 2009 Feb;104(2):356-62. PubMed
- 3. Mazumdar K, Dutta NK, Dastidar SG, Motohashi N, Shirataki Y. Diclofenac in the management of E. coli urinary tract infections. In Vivo. 2006 Sep-Oct;20(5):613-9. PubMed
- 4. Zhang YK, Yang H, Zhang JY, Song LJ, Fan YC. Comparison of intramuscular compound betamethasone and oral diclofenac sodium in the treatment of acute attacks of gout. Int J Clin Pract. 2014 May;68(5):633-8. PubMed
- 5. Zuinen C. Diclofenac/misoprostol vs diclofenac/placebo in treating acute episodes of tendinitis/bursitis of the shoulder. Drugs. 1993;45 Suppl 1:17-23. PubMed
- 6. Maquirriain J, Kokalj A. Management of acute Achilles tendinopathy. Georgian Med News. 2013 Sep;(222):36-43. PubMed
- 7. Ximenes A, Robles M, Sands G, Vinueza R. Valdecoxib is as efficacious as diclofenac in the treatment of acute low back pain. Clin J Pain. 2007 Mar-Apr;23(3):244-50. PubMed
- 8. Zerbini C, Ozturk ZE, Grifka J, et al. Efficacy of etoricoxib 60 mg/day and diclofenac 150 mg/day in reduction of pain and disability in patients with chronic low back pain: results of a 4-week, multinational, randomized, double-blind study. Curr Med Res Opin. 2005 Dec;21(12):2037-49. PubMed
- 9. Bhattarai S, Chhetri HP, Alam K, Thapa P. A study on factors affecting low back pain and safety and efficacy of NSAIDs in acute low back pain. J Clin Diagn Res. 2013 Dec;7(12):2752-8
By HealthyStock Research Group, September 2009
Medical resources reviewed: August 2018
