What is the recommended dosing for Arthrotec (diclofenac and misoprostol) in treating osteoarthritis and rheumatoid arthritis?

Arthrotec Dosing for Osteoarthritis and Rheumatoid Arthritis

For osteoarthritis, start Arthrotec 50 (diclofenac 50mg/misoprostol 200mcg) twice daily, and for rheumatoid arthritis, start with three times daily dosing, with the option to increase to four times daily if needed. 1

Standard Dosing Regimens

Osteoarthritis

• Initial dose: Arthrotec 50 (diclofenac 50mg/misoprostol 200mcg) taken twice daily 1
• Alternative dosing: Can use three times daily if twice daily dosing provides inadequate relief 1
• Total daily diclofenac range: 100-150 mg/day in divided doses 1

Rheumatoid Arthritis

• Initial dose: Arthrotec 50 taken three times daily 1, 2
• Maximum dose: Can increase to four times daily (200 mg diclofenac total) if three times daily is insufficient 1
• Total daily diclofenac range: 150-200 mg/day in divided doses 1

Formulation Details

Arthrotec is available in two formulations: 3

• Arthrotec 50: Diclofenac 50mg core with misoprostol 200mcg mantle 3
• Arthrotec 75: Diclofenac 75mg core with misoprostol 200mcg mantle 3

The misoprostol component provides gastroprotection by reducing gastroduodenal ulcers compared to diclofenac alone. 3, 4

Efficacy Evidence

• Arthrotec demonstrates equivalent antiarthritic efficacy to diclofenac alone while providing significantly fewer gastroduodenal erosions and ulcers 4
• Clinical trials in 1824 patients with RA or OA showed Arthrotec was as effective as diclofenac, naproxen, piroxicam, indomethacin, and ibuprofen 3
• The combination achieved significant reduction in both gastric and duodenal ulcers compared to other NSAIDs 3

Safety Profile and Common Adverse Events

The most frequent adverse events are gastrointestinal: 2, 5

• Abdominal pain: 23.2% (vs 19.8% with diclofenac alone) 2
• Diarrhea: 19.9% (vs 11.3% with diclofenac alone) - rated mild in 24.3%, moderate in 51.4%, severe in 24.3% 2
• Nausea: 11.8% (vs 6.5% with diclofenac alone) 2
• Dyspepsia: 11.2% (vs 7.8% with diclofenac alone) 2

Most adverse events are mild to moderate in severity, with withdrawal rates similar between Arthrotec and diclofenac alone (12.6% vs 10.1%). 2

Critical Prescribing Considerations

When to Use Arthrotec

• Arthrotec is specifically designed for patients requiring NSAID therapy who are at risk for gastroduodenal complications 3
• The built-in misoprostol provides gastroprotection without requiring separate prescriptions 6, 4

Dose Adjustment Strategy

• Start at the lower end of the dosing range 1
• Adjust dose and frequency based on individual patient response after observing initial therapy 1
• Use the lowest effective dose for the shortest duration to minimize adverse effects 1

Important Caveats

• Do not combine with other NSAIDs - this increases adverse effects without additional benefit 7, 8
• Different diclofenac formulations are not bioequivalent even at the same milligram strength, so do not substitute freely 1
• Diarrhea management: If diarrhea occurs, it typically resolves with continued use or dose reduction 2, 5
• Contraindication in pregnancy: Misoprostol is an abortifacient and contraindicated in women of childbearing potential unless using effective contraception 5

Long-Term Use Data

• Long-term studies (up to 24 months) show continued efficacy and tolerability 5
• Adverse events remain predominantly gastrointestinal and do not increase substantially with prolonged use 5
• Regular monitoring of hepatic and renal function is warranted, though laboratory abnormalities are similar to diclofenac alone 2