Anti-Rheumatic Drugs - Drugs used for arthritic disorders Flashcards
Treatment of osteoarthritis (3)
- Pain Relief & Anti-inflammatory
- Acetaminophen, non-selective NSAIDs, COX-2 inhibitors, glucocorticoids - Viscosupplementation
- Intra-articular hyaluronic acid - shock absorption, protective coating of cartilage, lubrication, reduce pain, induce biosynthesis of hyaluronic acid & ECM - Symptomatic slow-acting drugs for OA
- Chondroitin sulphate, glucosamine
Classes of drugs used in gouty arthritis & examples
Anti-Inflammatory: relieve acute gouty attack
- NSAIDs & COX-2 inhibitors (indomethacin, naproxen, celecoxib)
- Glucocorticoids (prednisolone - oral/intra-articular injection)
- Colchicine
Urate-Lowering Therapy: prevent recurrent gouty episodes
- Xanthine oxidase inhibitors (Allopurinol, Febuxostat)
- Uricosuric agents (Probenecid, sulfinpyrazone)
NSAIDs & COX-2 inhibitors in gouty arthritis
- Inhibit production of prostaglandins & urate crystal phagocytosis
- Contraindications: low dose of aspirin/salicylates - anti-uricosuric actions
Mechanism of action of colchicine
- Binds to tubulin - prevents tubulin polymerization into microtubules
- Inhibits leukocyte migration & phagocytosis, inhibits leukotriene B4 production
Uses of colchicine
- Relieve pain & inflammation in acute gouty attack in 12-24h (fast action)
Toxicity of colchicine (3)
- Diarrhea, nausea, vomiting, abdominal pain
- Muscle weakness
- Allergic reactions `
Mechanism of allopurinol
Decreases uric acid production by inhibiting xanthine oxidase enzyme (oxidation of xanthine to uric acid)
Uses of allopurinol (3)
- Debilitating gout attacks (target uric acid<6.0mg/dL)
- Chronic erosive arthritis
- Urate nephrolithiasis
Toxicity of allopurinol (5)
- Allopurinol Hypersensitivity Syndrome eg Stevens-Johnson syndrome - risk factors - renal impairment with creatinine clearance <60ml/min, thiazide therapy, HLA-B58 antigen
- Skin rash
- Vasculitis
- Diarrhea
- Hepatitis
Mechanism of action of uricosuric agents
Inhibits anion transport sites at proximal tubule - inhibits uric acid reabsorption + increases uric acid excretion
Uses of uricosuric agents (3)
- When allopurinol is contraindicated
- Tophaceous gout
- Increasingly frequent gouty attack
Toxicity of uricosuric agents (4)
- Allergic reactions, rash, swelling
- Nephrotic syndrome
- Severe lower back pain
- Maintain large urine volume to prevent urolithiasis, increase urine pH by alkali eg potassium citrate
Classes of drugs used in rheumatoid arthritis & examples
Anti-Inflammatory
- NSAIDs - short term relief of pain & stiffness + PPI to reduce GI side effects
- Glucocorticoids
Synthetic/Non-biologic DMARDs
- Methotrexate +
- Hydroxychloroquine (best tolerated) or sulfasalazine, leflunomide, immunosuppressants
Biological DMARDs
- Anti-TNF-α (Infliximab, adalimumab, etanercept)
- Anti-IL-1 receptor (anakinra)
- Anti-CD20 (rituximab)
- Anti-CTLA41g (abatacept)
- Anti-IL-6 receptor (tocilizumab)
Mechanism of action of methotrexate
- Folic acid analog, inhibits AICAR transformylase
- Inhibits thymidylate synthetase
- Inhibits dihydrofolate reductase (minor)
- Increases extracellular adenosine levels & activates adenosine A2a receptor
- anti-proliferative effects on T cells & inhibition of macrophage function
- decrease in pro-inflamm cytokines, adhesion molecules, chemotaxis, phagocytosis
Toxicity of methotrexate (5)
- Myelosuppression
- Mouth & GI ulcers
- Hepatic fibrosis
- Pneumonitis
- Teratogenic effects
- Concomitant folic/folinic acid given 12-24h after methotrexate decreases toxicity
Mechanism of action & uses of hydroxychloroquine
- Mechanism unclear, involves suppression of T cell response, decreased chemotaxis & inhibition of DNA & RNA synthesis
- Used with methotrexate in RA
- Anti-malarial agent
Toxicity of hydroxychloroquine (3)
- Ocular toxicity
- Dyspepsia
- Nausea, vomiting
Mechanism of action of sulfasalazine
- Decreased IgA & IgM rheumatoid factors
- Suppression of T & B cells, and macrophages
- Decrease in inflammatory cytokines eg IL-1β, TNF-α, IL-6
Toxicity of sulfasalazine (5)
- Nausea, vomiting
- Headache
- Rash
- Hemolytic anemia, neutropenia
- Reversible infertility in men
Mechanism of action of leflunomide
- Inhibits dihydroorotate dehydrogenase
- Decrease in pyrimidine synthesis & growth arrest at GI phase
- Inhibits T cell proliferation & B cell autoantibody production
- Inhibits NF-kB activation pro-inflammatory pathway
Toxicity of leflunomide (5)
- Diarrhea
- Elevation of liver enzymes
- Alopecia
- Weight gain
- Teratogenic
Uses of anti-TNF-α
- RA patients who do not respond well with DMARD therapy
2. Used with methotrexate for optimal effects (and prevents human anti-chimeric Ab prod)
Toxicity of anti-TNF-α & Contraindications (7+2)
- Respiratory infection
- Skin infection
- Increased risk of lymphoma
- Optic neuritis
- Exacerbation of multiple sclerosis
- Leukopenia
- Aplastic anemia
- Live vaccination
- Hepatitis B
Mechanism of action of anakinra
- Recombinant IL-1R antagonist, binds to IL-1 receptor - bloocks signalling
- less effective than anti-TNF
Toxicity of anakinra (2)
- Infections
2. Injection site reactions
Mechanism of action of rituximab
- Chimeric mAb IgG directed at CD20 on B cells - depletes CD20+ B cells
- Blocks Ag presentation, autoantibody & cytokine level
Toxicity of rituximab (2)
- Rash in first dose
2. Respiratory infection in COPD
Mechanism of action & uses of abatacept
Recombinant fusion protein with CTLA4-FcIgG1 (IV), binds to CD80 & CD86 & prevents CD28 activation
- T cell therapy, IV
Toxicity of abatacept (2)
- Respiratory infection in COPD
2. Increased lymphoma incidence
Mechanism of action of tocilizumab
Humanized mAb IgG1 directed at IL-6Rα chain - prevents binding of IL-6 to IL-6Rα and homodimerization of IL-6Rβ signalling
Toxicity of tocilizumab (7)
- Infections
- Skin eruptions
- Stomatitis
- Fever
- Neutropenia
- Increase in ALT/AST
- Hyperlipidemia