methotrexate

Question 1

METHOTREXATE:
What is it indicated for?

Answer 1

inflammatory disorders;
rheumatoid arthritis
psoriatic arthritis

Neoplastic disorders;
cancer

Question 2

METHOTREXATE:
what is its mechanism of action?

Answer 2

inhibits dihydrofolate reductase

also has antiinflammatory and immunosuppressive effects

Question 3

METHOTREXATE:
What are side effects?

Answer 3

mucosal damage
bone marrow suppression

neurological effects;
headaches, seizures, coma

hypersensitivity reaction

Question 4

METHOTREXATE:
What can once weekly administration cause?

Answer 4

renal impairment and hepatoxicity

Question 5

METHOTREXATE:
what can going term use cause?

Answer 5

liver cirrhosis
lung fibrosis

Question 6

METHOTREXATE:
How is methotrexate toxicity treated?

Answer 6

folinic acid
hydration
urinary alkalisation to enhance its excretion

Question 7

METHOTREXATE:
What are warnings?

Answer 7

teratogenic
contraindicated in renal impairment
Avoided-hepatic impairment

Question 8

METHOTREXATE:
What are important interactions?

Answer 8

Drugs that inhibit its renal excretion
aspirin, NSAIDs, penicillins

folate antagonist; trimethoprim, phenytoin

neutropenia; clonazapine

Question 9

METHOTREXATE:
What are dosages for inflammatory disease?

Answer 9

7.5mg to 20mg orally once a week

Question 10

METHOTREXATE:
What are monitoring requirements

Answer 10

measure FBC, liver, renal function before starting then every 1-2 weeks until treatment is established.

2-3 times monthly thereafter.

Question 11

What are cautions?

Answer 11

blood count-bone marrow suppression
GI toxicity
pulmonary toxicity
liver toxicity
Dehydration

Question 12

What are MHRA warnings?

Answer 12

Never Event;
Overdose in non-cancer treatment

Once weekly administration for auto-immune diseases, new measures to reduce risk of fatal overdose due to inadvertently daily dosing

Advise precautions in the sun to avoid photosensitivity reactions

Question 13

What advice should be given regarding MHRA warning about photosensitivity?

Answer 13

Photosensitivity reactions including phytotoxicity are known side effects

Advise patients to;
avoid exposure to UV light
Use sunscreen with a high sun protection factor and wear protective clothing during sun exposure

speak to HCP if they have concerns about a skin reaction.

Question 14

How long should contraception be used for during and after treatment in men and women?

Answer 14

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