DOSE RESPONSE RELATIONSHIP OF HYDROXYCHLOROQUINE SULPHATE IN THE TREATMENT OF RHEUMATOID ARTHRITIS: A RANDOMISED CONTROL STUDY

Background: RA is an autoimmune disease triggered by faulty immune system and affects various joints of body including wrist and finger. Nowadays slow acting or DMARDs (Disease modifying anti-rheumatoid drugs) are mainstay of treatment in RA. HCQs belong to this group. They are slow acting so they take weeks to months to become effective. HCQ is less effective when compared to gold or penicillamine but its tolerance is better than other DMARDs. Objective: 1. To observe a  dose–response relationship for hydroxychloroquine (HCQ), in terms of the proportion of patients achieving the Paulus 20% criteria for improvement  in patients with rheumatoid arthritis (RA) receiving a 24 week loading regimen of 400, 800, or 1,200 mg HCQ daily. 2. To investigate possible relationships between increased dosage of HCQ   and measures of efficacy and toxicity. Methods:  422 Patients with RA began a 24-week study comparing 3 different doses of HCQ at 400, 800, or 1,200 mg/day, followed by 18 weeks of open-label HCQ treatment at 400 mg/day. Patients were evaluated at 0, 6 and 18 week to measure the efficacy and adverse reaction of the drug. Results: There was a positive correlation between the Paulus 20% improvement criteria response and increased dose of HCQs during weeks 1-6 (P < 0.001). Adverse gastrointestinal events were associated with higher HCQ levels (P <=0.001) during 0-3 weeks. Conclusion: There is a weak, but predictable, relationship between increase HCQs dosage and efficacy of treatment with HCQ.