Musculoskeletal Flashcards
Which of these drugs is NOT a DMARD?
- Methotrexate
- Gold
- Leflunamide
- Colchicine
- Hydroxychloroquine
Colchicine
How long do DMARDs take to work?
Varies, but can take 2-6 months for full effect
When should a DMARD be changed for a different one?
If not objective benefit in 6-12 months
How does methotrexate work?
Anti-folate - inhibtis dihydrofolate reductase
Prevents cellular replication
Dose of MTX for these conditions?
- RA
- Crohns
- Psoriasis
RA - max 20mg weekly
Crohns - 10-25mg weekly
Psoriasis - max 30mg weekly
What should a methotrexate prescription include?
- Dose
- Frequency
- Only one strength should be prescribed and dispensed
Contra-indications for MTX?
- Active infection - as immunosuppression
- Ascites - as risk of accumulation
- Immunodeficiency syndrome
What can increase the risks of toxicity from methotrexate?
- Increasing age
- Renal impairment
- Use of other anti-folates eg, trimethoprim
How does the BNF recommend folic acid is used with methotrexate?
5mg weekly on a different day to methotrexate
Why is folic acid given with methotrexate?
To reduce GI and mucosal side effects and may prevent hepatotoxicity
What advice should be given to patients about contraception whilst on methotrexate?
Effective contraception should be used during treatment and for at least 3 months after treatment in both men and women
MTX is teratogenic and fertility may be reduced
Can MTX be used in hepatic and renal impairment?
- Avoid in hepatic impairment unless it is for malignancy
- High doses may be neprotoxic - moniotr renal func
What patient counselling should be given with methotrexate?
- Use effective contraception during + 3 months following treatment
- Avoid OTC NSAIDs
- Report any signs of blood disorders, liver toxicity or pulmonary toxicity
What monitoring is required for methotrexate?
FBC + renal and liver function tests
Every 2 weeks until treatment stabilised
Which blood disorders may be caused by methotrexate?
Decreased WBCS - signs of infection
Decreased RBCs - signs of anaemia
Decreased platelets - bruising and bleeding
What are some interactions with methotrexate?
NSAIDs - reduced renal excretion due to vasoconstriction of arteries can lead to toxicity
Drugs with risk of blood disorders - phenytoin, trimethoprim, clozapine etc
Hepatotoxic drugs - isotretinoin, rifampicin, ketoconazole
What monitoring is required for a patient on hydroxychloroquine?
Monitor vision/visual changes - risk of ocular toxicity with long-term treatment
- Before treatment determine baseline vision and renal/liver func and adjust dose if necessary
- Monitor vison annually and ask pt to report any changes eg, blurred vision
What patient couselling should be given with Leflunomide?
- Risk of blood disorders, report any signs and need FBC monitoring
- Risk of liver toxicity - do not drink alcohol and LFTs need to be taken every 2 weeks for the first 6/12, potentially life-threatening
- Contraception is essential during treatment, continue for 2 years after treatment in women and 3 months in men
Why might leflunomide need a ‘wash-out’ with activated charcoal or colestyramine?
Has a very long half life
May need a washout if serious side effects occur, before another DMARD is initiated or before conception
How long do men and women who want to concieve have to wait following treatment with leflunomide?
Men - 3 months of effective contraception
Women - 2 years following treatment
Sr levels must be <20mcg/L before conception
Can you give penicillamine to a patient with a penicillin allergy?
No, patients with penicillin allergy may rarely react to penicillamine
What is sodium aurothiomalate?
Gold - DMARD
What are the major side effects of Gold?
- Blood disorders
- Pulmonary fibrosis - annual chest xray
- Rashes with pruritis
- Nephritis + proteinuria, need regular urine tests
Which of these would NOT cause hyperuricaemia/gout?
- Tacrolimus
- Cancer
- Liver impairment
- Furosemide
- Chemotherpay
Liver impairment
How should an acute gout attack be treated?
- High doses of NSAIDs
diclofenac, naproxen, etoricoxib, indometacin, ketoprofen - If NSAIDs C/I then colchicine
- Oral/parenteral corticosteroids
Which NSAIDs are NOT indicated in the treatment of an acute gout attack?
Ibuprofen + aspirin
How should colchicine be prescribed in an acute gout attack?
500mcg 2-4 times/day
No more than 6mg in a course, do not repeat the course within 3 days
How would you treat an acute gout attack in a patient with severe heart failure?
Colchicine - no fluid retention
All NSAIDs are contra-indicated in severe heart failure
How should long term prevention for gout be initiated?
- Never in an acute attack, 1-2 weeks after attack has settled
- Initiation of treatment may precipitate an acute attack, use prophylactic NSAID/colchicine until hyperuricaemia has been corrected for one month
How would you treat an acute gout attack in a patient taking allopurinol?
- Continue allopurinol in same dosage
- Treat attack separately with high-dose NSAIDs/colchicine
What drug is first line for gout prophylaxis?
Allopurinol