RHEUM: drugs

Question 1

What should be used for Gout if NSAIDS are not suitable?

Give an example of pt where NSAIDS not suitable?

Answer 1

Pts not suitable for NSAIDS :
Renal impairment
Significant heart disease

2nd line choice:
Colchicine

Side effects of Colchicine are GI upset and diarrohea

Question 2

Name 2 differentials of poly myalgia rheumatica

Answer 2

Osteoarthritis, rheumatoid arthritis, SLE, myositis, cervical spondylitis, frozen shoulder (in both shoulders), hyper or hypo thyroidism, osteomalacia, fibromyalgia

Question 3

Never give methotrexate and which AB?

Answer 3

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

Question 4

You have prescribed a lady alendronic acid as a recent XR shows signs of osteoporosis. What advice would you give her about this drug?

Answer 4

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.

Question 5

What drug(s) are used for acute attacks of gout or pseudogout?

Answer 5

NSAIDs
Colchicine
Intra articular steroid injections

Question 6

In what patients should colchicine be avoided?

Answer 6

Patients with renal failure

Question 7

What drug is used for prophylaxis of gout/pseudogout?

Answer 7

Allopurinol

Question 8

What is mechanism of action of methotrexate?

Answer 8

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).

Question 9

What are ADRs of methotrexate?

Answer 9

V common: Nausea.

Other: oral ulcers, hair thinning, hepatitis, cirrhosis, pneumonitis, bone marrow suppression

Question 10

Who should not be prescribed methotrexate and why?

Answer 10

Pregnancy - teratogenic.
Severe renal impairment - it is renally excreted
Abnormal liver function - causes hepatotoxicity

Question 11

What is sulfalazine’s mechanism of action?

Answer 11

Release 5-aminosalicylic acid (5-ASA) which has anti-inflammatory and immunosuppressive effects

Question 12

What are ADRs of Sulfasalazine?

Answer 12

V common: GI upset

Other: rash, hepatitis, bone marrow suppression

Question 13

In which patient groups is sulfasalazine contraindicated and why?

Answer 13

In pts with aspirin hypersensitivity. Sulfasalazine and Aspirin are both part of the salicylates group

Question 14

What is the mechanism of action of azathioprine?

Answer 14

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.

Question 15

Why is TMPT activity/phenotyping tested in patients before prescribing azathioprine?

Answer 15

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.

Question 16

What are side effects of azathioprine?

Answer 16

GI upset - v common

Bone marrow suppression

Question 17

What are ADRs of cyclophosphamide?

Answer 17

Bone marrow suppression, infertility and increased cancer risk. Haemorrhagic cystitis

Question 18

What are ADRs of hydroxychloroquine?

Answer 18

V common: GI upset

Other: retinal pigmentation and loss of vision - rare but need to be screened.

Question 19

What mechanism of action do DMARDs Ciclosporin and tacrolimus have?

Answer 19

Calcineurin inhibitors - these are active against T helper cells.

Question 20

what type of anaemia can sulfasalazine cause?

Answer 20

Heinz body

Question 21

What drug can cause gingival enlargement?

Answer 21

cyclosporin

Question 22

DMARD that causes myelosupression

Answer 22

Azthioprine

Methotrexate- worsened by renal impairment and certain drugs eg trimethoprim

Question 23

Which drugs can increase risk of gout?

Answer 23

Diuretics- particularly thiazide like and loop
pyrazinamide
ciclosporin
tarcolimus

Question 24

Allopurinol - mechanism of action?

Answer 24

Xanthine oxidase inhibitor so reduces rate formation.