From the FDA Drug Label
DOSAGE AND ADMINISTRATION Carefully consider the potential benefits and risks of diclofenac potassium tablets and other treatment options before deciding to use diclofenac potassium tablets. Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals (see WARNINGS: Gastrointestinal Bleeding, Ulceration, and Perforation) After observing the response to initial therapy with diclofenac potassium tablets, the dose and frequency should be adjusted to suit an individual patient's needs. For treatment of pain or primary dysmenorrhea the recommended dosage is 50 mg three times a day With experience, physicians may find that in some patients an initial dose of 100 mg of diclofenac potassium tablets, followed by 50 mg doses, will provide better relief. For the relief of osteoarthritis, the recommended dosage is 100-150 mg/day in divided doses, 50 mg twice a day or three times a day For the relief of rheumatoid arthritis, the recommended dosage is 150-200 mg/day in divided doses, 50 mg three times a day or four times a day. The dosing of diclofenac is as follows:
- Pain or primary dysmenorrhea: 50 mg three times a day
- Osteoarthritis: 100-150 mg/day in divided doses, 50 mg twice a day or three times a day
- Rheumatoid arthritis: 150-200 mg/day in divided doses, 50 mg three times a day or four times a day 1
From the Research
Diclofenac dosing should be 150mg/day for optimal efficacy in treating osteoarthritis, as it has been shown to be more efficacious than ibuprofen 1200mg/day and have likely favourable outcomes for pain relief compared to ibuprofen 2400mg/day 2.
Dosing Considerations
- For oral immediate-release tablets, the typical adult dose is 50 mg 2-3 times daily or 75 mg twice daily, with a maximum daily dose of 150 mg.
- Extended-release formulations are usually dosed at 100 mg once daily.
- Topical diclofenac gel (1%) is applied 2-4 times daily with 2-4 grams per application to affected areas.
- Injectable diclofenac is typically 75 mg given intramuscularly once or twice daily.
Important Considerations
- Dosing should be reduced in elderly patients and those with renal or hepatic impairment.
- Treatment duration should be limited to the shortest period necessary to control symptoms due to potential cardiovascular and gastrointestinal risks.
- These risks increase with dose and duration of use.
- Diclofenac works by inhibiting cyclooxygenase enzymes (COX-1 and COX-2), reducing prostaglandin synthesis and thereby decreasing inflammation, pain, and fever.
- Taking oral diclofenac with food and using gastroprotective agents like proton pump inhibitors may help reduce gastrointestinal side effects.
Key Points
- The benefit-risk profile of diclofenac is comparable to other treatments used for pain relief in osteoarthritis and rheumatoid arthritis 3.
- Diclofenac has been shown to be effective in treating nociceptive pain and chronic central pain 4.
- The mechanisms of action of diclofenac make it particularly effective in treating both nociceptive pain and chronic central pain.