Diclofenac inhibits the activity of the enzyme cyclo - oxygenase, resulting in decreased formation of precursors of prostaglandins and thromboxanes from arachidonic acid.
Diclofenac may block pain impulse generation via a peripheral action that may involve reduction of the activity of prostaglandins, and possibly inhibition of the synthesis or actions of other substances that sensitize pain receptors to mechanical or chemical stimulation.

Tendinitis; Edema post-operation or post trauma; Local symptomatic relief of pain and inflammation.

This medication should not be used when the following medical problems exist:
Allergic reaction, severe, such as anaphylaxis or angioedema, induced by aspirin or other NSAIDs, history of; Nasal polyps associated with bronchospasm, aspirin - induced (high risk of severe allergic reactions because of cross - sensitivity); Blood dyscrasis, active or history of; Bone marrow depression (diclofenac may induce or exacerbate these conditions).
Risk benefit should be considered when the following medical problems exist:
Allergic reaction, mild, such as allergic rhinitis, urticaria, or skin rash, induced by aspirin or other NSAIDs, history of (possibility of cross - sensitivity); Anemia; Asthma; Hypertension: Edema; Inflammatory or ulcerative disease of the upper or lower gastrointestinal tract; Diabetes mellitus; Hemophilia or other bleeding problems; hepatic or renal function impairment; Stomatitis; Systemic lupus erythematosus; Porphyria, ( diclofenac may precipitate an acute attack); Eczema; Infected lesions or wounds.

Embryotoxicity and other adverse effects, but not teratogenicity, demonstrated in animal studies.
FDA Pregnancy Category B.

Diclofenac is distributed into breast milk.

In addition to the interactions listed below, the possibility should be considered that additive or multiple effects leading to impaired blood clotting and / or increased risk of bleeding may occur if any NSAID is used concurrently with any medication having a siginficant potential for causing hypoprothrombinemia, thrombocytopenia, or gastrointestinal ulceration or hemorrhage.
Acetaminophen, Alcohol, Potassium supplements, Anticoagulants, Heparin, Thrombolytic agents, Potassium-sparing diuretics, Lithium, Probenecid, Salicylates, Digoxin, Antidiabetic agents or insulin, Corticosteroids, Cyclosporine, Valproic acid.

Hypersensitivity reactions such as:
Rhinosinusitis / asthma or angioedema / urticaria; Anaphylaxis.
Gastrointestinal problems; Dermatologic effects; Headache; Renal and hepatic function impairment; Hearing problems, CNS effects; Hyperkalemia; Edema.

Usual adult, adolescent, children (15 years of age and over):
It is applied to the affected site 3 to 4 times daily; Treatment should be reviewed after 14 days or after 28 days if used for osteoarthritis.