Methotrexate

Question 1

What are the SSx of methotrexate toxicity?

Answer 1

Lymphopenia
Thrombocytopenia
Pallor
Nausea + Vomiting
GI bleeding
Dysuria/Anuria

Question 2

What are 4 risk factors for methotrexate toxicity?

Answer 2

Hypoalbuminemia
Folic acid deficiency
Concomitant drug treatments i.e NSAIDs that reduce elimination of methotrexate
Ascites or effusions that can act as depots as methotrexate distributes well into tissue fluid

Question 3

What is the rescue therapy for methotrexate?

Answer 3

Stop methotrexate
Consult a haematologist/toxicologist
Give folinic acid
Consider G-CSF

Question 4

Name 3 investigations to carry out while on methotrexate

Answer 4

LFT (TRO hepatotoxicity)
FBC (TRO blood dyscrasia)
eGFR
U + E

Question 5

Is methotrexate safe to use in pregnancy?

Answer 5

No

Question 6

What is the purpose of giving folic acid with methotrexate?

Answer 6

Reduces chances of hepatotoxicity, mucosal and GI side effects.

No evidence of reduction in haematological side effects

Question 7

What is the advice surrounding methotrexate in men and women who want to get pregnant?

Answer 7

Manufacturer advises effective contraception during and for at least 6 months after treatment in men and women.

Question 8

What are some side effects of methotrexate administration?

Answer 8

Blood dyscrasias (sore throat, mouth ulcer, bruising)
Liver toxicity (N+V, abdominal pain, dark urine)
Methotrexate pneumonitis (SOB)

Question 9

How do you take folic acid with methotrexate?

Answer 9

Take on a different day to methotrexate once weekly (methotrexate taken once weekly).

Note: may also have to take folic acid once daily