methotrexate

Question 1

what is methotrextae

Answer 1

folic analogue
- inhibits dihydrofiloc reductase
which is important in synthesis of nucleotides

decreased thymine

DMARD
immunosuppressant

Question 2

how to prescribe / take methotrexate

Answer 2

• taken weekly
• 5mg OW folic acid prescribed too - not on the same day
• starting dose usually 7.5mg - methotrexate

Question 3

adverse effects

Answer 3

• mucositis
• myelosuppression
• pneumonitis
• pulmonary fibrosis
• liver fibrosis

Question 4

monitoring

Answer 4

FBC, U&E and LFTs need to be regularly monitored. The Committee on Safety of Medicines recommend
- FBC and renal and LFTs before starting treatment and repeated weekly until therapy stabilised, thereafter patients should be monitored every 2-3 months

Question 4

Pregnancy

Answer 4

• women should avoid pregnancy for at least 6 months after treatment has stopped
• men using methotrexate need to use effective contraception for at least 6 months after treatment

Question 5

Interactions

Answer 5

• trimethoprim
• co-amoxiclav
• high dose aspirin