METHOTREXATE

Question 1

What are the warning signs of methotrexate that require immediate referral to the doctor

Answer 1

Gastrointestinal toxicity- inflamed mount or throat may be the first sign

Liver toxicity- jaundice, nausea, vomiting, abdominal discomfort, dark urine

Blood disorders- bone marrow suppression- sore throat, bruising, mouth ulcers, fever, rash

Pulmonary toxicity- pneumonitis (dyspnoea, cough)

Pregnancy and breast feeding

Question 2

What are the monitoring requirements of methotrexate

Answer 2

Full blood count

Renal function test

Liver function tests

Repeated after 1-2 weeks until therapy stabilised then every 2-3 months

Question 3

What are the main interactions with methotrexate

Answer 3

AVOID in acitretin as it can increase plasma concentration and increase hepatotoxicity risk

Excretion reduced by NSAIDs and penicillins, increased risk of toxicity

Increased risk of toxicity with ciprofloxacin and doxycycline, tetracycline, ciclosporin, PPIs and leflunomide

Increased risk of haematological toxicity when given with trimethoprim and co-trimoxazole

Question 4

What are the other counselling points you should consider when taking methotrexate

Answer 4

Take once a week on the same day and with folic acid

Counsel patients on importance of effective contraception during treatment

Avoid preparations containing NSAIDs and aspirin

Folinic acid helps prevent methotrexate-induced mucositis or myelosuppression

Methotrexate treatment books given when appropriate

Question 5

What are the implications of methotrexate on pregnancy and breast feeding

Answer 5

AVOID teratogenic