RHEUM: drugs Flashcards
What should be used for Gout if NSAIDS are not suitable?
Give an example of pt where NSAIDS not suitable?
Pts not suitable for NSAIDS :
Renal impairment
Significant heart disease
2nd line choice:
Colchicine
Side effects of Colchicine are GI upset and diarrohea
Name 2 differentials of poly myalgia rheumatica
Osteoarthritis, rheumatoid arthritis, SLE, myositis, cervical spondylitis, frozen shoulder (in both shoulders), hyper or hypo thyroidism, osteomalacia, fibromyalgia
Never give methotrexate and which AB?
Never give methotrexate and trimethoprim
Causes: Bone marrow suppression and severe or fatal pancytopaenia
Pt might present with : infection, bleeding anaemia
Adverse effect made worse by renal impairment
You have prescribed a lady alendronic acid as a recent XR shows signs of osteoporosis. What advice would you give her about this drug?
Should take on an empty stomach.
Other drugs and food should be avoided for at least 30mins after taking it.
This is to maximise gut absorption.
Swallow whole with water and avoid bending down for 30mins - reduce indigestion SE.
What drug(s) are used for acute attacks of gout or pseudogout?
NSAIDs
Colchicine
Intra articular steroid injections
In what patients should colchicine be avoided?
Patients with renal failure
What drug is used for prophylaxis of gout/pseudogout?
Allopurinol
What is mechanism of action of methotrexate?
Inhibits dihydrofolate reductase.
Relevance - this ^ converts folic acid to tetrahydrofolate which is usually needed for DNA and protein synthesis. - so without it, cells can’t replicate (v important in cells actively dividing, e.g. cancer cells).
What are ADRs of methotrexate?
V common: Nausea.
Other: oral ulcers, hair thinning, hepatitis, cirrhosis, pneumonitis, bone marrow suppression
Who should not be prescribed methotrexate and why?
Pregnancy - teratogenic.
Severe renal impairment - it is renally excreted
Abnormal liver function - causes hepatotoxicity
What is sulfalazine’s mechanism of action?
Release 5-aminosalicylic acid (5-ASA) which has anti-inflammatory and immunosuppressive effects
What are ADRs of Sulfasalazine?
V common: GI upset
Other: rash, hepatitis, bone marrow suppression
In which patient groups is sulfasalazine contraindicated and why?
In pts with aspirin hypersensitivity. Sulfasalazine and Aspirin are both part of the salicylates group
What is the mechanism of action of azathioprine?
Azathioprine is a prodrug (so when metabolised it makes substances that are pharmacologically active). It is metabolised to 6-MP which is further metabolised.
These breakdown products inhibit the synthesis off purines, so inhibit DNA replication.
Why is TMPT activity/phenotyping tested in patients before prescribing azathioprine?
1) Levels of TPMT vary amongst people.
2) Metabolism and elimination of azathioprine and its metabolites requires TPMT.
3) If you don’t have TPMT, metabolites convert to another substance which can cause myelosuppression - not v good.
What are side effects of azathioprine?
GI upset - v common
Bone marrow suppression
What are ADRs of cyclophosphamide?
Bone marrow suppression, infertility and increased cancer risk. Haemorrhagic cystitis
What are ADRs of hydroxychloroquine?
V common: GI upset
Other: retinal pigmentation and loss of vision - rare but need to be screened.
What mechanism of action do DMARDs Ciclosporin and tacrolimus have?
Calcineurin inhibitors - these are active against T helper cells.
what type of anaemia can sulfasalazine cause?
Heinz body
What drug can cause gingival enlargement?
cyclosporin
DMARD that causes myelosupression
Azthioprine
Methotrexate- worsened by renal impairment and certain drugs eg trimethoprim
Which drugs can increase risk of gout?
Diuretics- particularly thiazide like and loop
pyrazinamide
ciclosporin
tarcolimus
Allopurinol - mechanism of action?
Xanthine oxidase inhibitor so reduces rate formation.
