Treatment Options for RA Flashcards
How many people in the UK have RA?
Over 400,000 (1% of UK population)
How many new cases are diagnosed each year?
12,000
Apart from the joints, what else does synovitis of RA affect?
Tendon sheaths
Increased coronary artery disease
Significant risk of premature mortality
Which joints are commonly affected?
What pattern - symmetrical or asymmetrical?
Small joints of hands and feet (MCP and PIP joints)
Symmetrical
How is RA diagnosed?
2010 ACR/EULAR criteria - for the target popualtion with at least 1 swollen joint, with no other explanation.
What are the categories for the 2010 ACR/EULAR criteria?
The categories are joint involvement (large/small joints and how many), serology (levels of RF and ACPA), acute phase reactants (normal or abnormal CRP and ESR), duration of symptoms (<6 weeks, >6 weeks).
Need > 6/10 for diagnosis.
What does RF stand for?
What does ACPA stand for?
Rheumatoid factor
Anti-citrullinated protein antibodies
What is used for pain relief in RA?
Follow guidelines as for OA - analgesics and NSAIDs,, COX-2 inhibitors
How is disease progression modified?
Disease modifying anti-rheumatic drugs (DMARDs) - conventional DMARDs or “biologicals”
What is used as adjunct therapy in RA?
Oral corticosteroid pulse
According to the NICE guidelines, what is the combination therapy treatment for newly diagnosed RA?
Combination of DMARDs as first-line treatment as soon as possible (methotrexate and at least one other DMARD plus short term glucocorticoids), ideally within 3 months of the start of persistent symptoms
According to the NICE guidelines, what is the monotherapy treatment for newly diagnosed RA?
When is this used?
DMARD monotherapy and concentrate on fast escalation to a clinically effective dose
When combination therapy isn’t appropriate e.g. comorbidities or pregnancy
According to the NICE guidelines, what is the treatment for recent-onset RA?
When disease is under control, try to reduce drug doses to levels that maintain disease control
According to the NICE guidelines, what is the treatment for established RA?
When disease is stable, reduce DMARD doseages
When starting new drugs, consider decreasing/stopping pre-existing ones
Arrange a prompt review if doses are decreased or stopped
What is the first choice/gold standard drug in RA?
Methotrexate
How is Methotrexate given?
Orally once a week on the same day (2.5mg tablets, start between 5-10mg a week)
Can also be given by subcut or IM injection
How long does it take for benefits to be seen on Methotrexate?
3-12 weeks
What does methotrexate inhibit? What group of patients can’t take it?
Folic acid inhibitor (a chemotherapy drug) - pregnant women. It targets proliferating cells.
How does methotrexate get into the cell and stop DNA and RNA production?
Uses the reduced folate carrier/transporter to be actively transported in the cell, becomes poly-glutamated (by folylpolyglutamate synthase) to form the active drug to inhibit dihydrofolate reductase, thereby blocking the conversion of dihydrofolate to tetrahydrofolate. As tetrahydrofolate stores are depleted, thymidylate (TMP) synthesis is reduced. This ultimately stops DNA and RNA synthesis (inhibits purine synthesis).
What two enzymes does methotrexate inhibit?
Dihydrofolate reductase
Thymidylate synthetase
What are the side effects of methotrexate? (2)
Can cause liver problems (damage)
Can affect blood count (anaemia)
What type of drug is Sulfasalazine?
What compounds does it combine?
Antibiotic
Combines sulfapyridine and salicylate with azo bond
How is Sulfasalazine administered?
Orally - start 500mg daily, gradually increased over 4 weeks to 1g twice a day.
How long before benefit is noted with Sulfasalazine?
12 weeks
How does Sulfasalazine work for RA?
Mode of action not well understood - it gets concentrated in connective tissue and serous fluids.
Sulfasalazine is not well absorbed across the gut. How much of the parent drug is absorbed?
How is it metabolised?
Less than 15%
Metabolised by gut bacteria into 5-ASA and sulfapyridine (better absorbed)
How can Sulfasalazine be used to treat ulcerative collitis and Crohn’s disease? Why does this reduce arthritic symptoms?
Sulfasalazine and metabolites stay in lamina propia in the gut and are weak COX inhibitors and inhibit folate-metabolising enzymes. They reduce gut inflammation and dampen down cytokine production.
Hydroxychloroquine - what type of drug is this?
Anti-malarial
How is Hydroxychloroquine administered?
Oral (with or after food) - start with 400mg daily and then reduced to 2-3 times a week.
How long until benefits are seen with Hydroxychloroquine?
12 weeks