HIGH RISK: Methotrexate

Question 1

Is there any legal issues?

Is there is any clinical issues?

Prescription retention and POM book?

Counselling?

Answer 1

No legal issues

Clinical issues: Methotrexate should not be taken EVERY day (never event). It should be taken once a week as a single dose at the same time and day each week.

Prescription retention: Send to NHS BSA at the end of the month

Nil POM book documentation

Counselling:

• Folic acid helps reduce the gastrointestinal side effects of methotrexate. It should not be taken on the same day as methotrexate.
• Do they take any other OTC including multivitamins?
• NSAIDs - interaction (although can monitor if low-dose (7.5mg) methotrexate)
• Report side effects: sore throat, dizziness, cough

Question 2

Questions 22-23 relate to a 60-year-old woman takes oral methotrexate 7.5 mg once weekly for rheumatoid arthritis.

She is complaining of nausea and loose stools since starting on methotrexate.

Which of the following is the most appropriate strategy to prevent the side effects that the patient is experiencing?

Select one:
A. Folic acid 5 mg daily
B. Folic acid 5 mg once a week, taken on a different day to methotrexate Correct
C. Folinic acid 15 mg every 6 hours for 24 hours
D. Rinse mouth with lignocaine mouthwash
E. Stop methotrexate immediately

Answer 2

Folic acid is indicated for the prevention of side effects from methotrexate however it needs to be taken on a different day to the methotrexate, otherwise it will reduce the effectiveness of the methotrexate. The use of folinic acid is reserved for use as a part of treatment protocols for methotrexate infusions.

The correct answer is: Folic acid 5 mg once a week, taken on a different day to methotrexate

Question 3

A 50-year-old man takes folic acid 5 mg once weekly, methotrexate 10 mg once weekly. He has been newly prescribed amoxicillin 500 mg three times a day for seven days.

Select one:
A. Bradycardia
B. Hypertensive crisis
C. Increased eGFR
D. Increased risk of bleeding
E. QT interval prolongation
F. Reduced eGFR
G. Tachycardia
H. Toxicity of either or both drugs

Answer 3

Amoxicillin is predicted to increase the risk of toxicity when given with methotrexate. Manufacturer advises monitor.

Ref: https://bnf.nice.org.uk/interaction/methotrexate-2.html

The correct answer is: Toxicity of either or both drugs

Question 4

A 46-year-old woman presents to the ED with persistent bloody diarrhoea, abdominal pain and fever. Her past medical history includes Crohn’s disease. A diagnosis of an acute flare of Crohn’s is suspected. She is admitted to the gastroenterology ward and commenced on a course of methotrexate.

Which of the following may be a side-effect of her treatment?

• Acute respiratory distress syndrome
• Increase in appetite
• Leukoplakia
• Pneumonitis
• Telogen effluvium

Answer 4

Pneumonitis

Methotrexate may cause pneumonitis

Important for meLess important

Pneumonitis is a recognised side-effect. If not promptly recognised pneumonitis can lead to irreversible pulmonary fibrosis. Hence the BNF recommends that the patient seeks medical attention if they experience dyspnoea, cough or fever; and that the physician should monitor for symptoms at each visit and discontinue if pneumonitis is suspected.

Acute respiratory distress syndrome is not a recognised side effect.

Telogen effluvium, a thinning of the hair, is not seen with methotrexate therapy. Other hair related side effects, such as alopecia, have been reported.

Leukoplakia is not seen with methotrexate therapy, however it may be seen in conditions such as HIV that suppress the immune system to a greater extent.

Methotrexate does not cause an increase in appetite, a decrease is more common.

Question 5

A 56-year-old woman with Rheumatoid arthritis presents with a 3-day history of dysuria, frequency and foul smelling urine. Urinalysis is positive for blood, nitrites, leukocytes and protein. You look at her repeat prescription and note that she is taking methotrexate for her Rheumatoid disease. She has no allergies. Which antibiotic is not appropriate to prescribe due to the risk of severe bone marrow suppression?

• Nitrofurantoin
• Trimethoprim
• Amoxicillin
• Cefalexin
• Co-amoxiclav

Answer 5

The concurrent use of methotrexate and trimethoprim containing antibiotics may cause bone marrow suppression and severe or fatal pancytopaenia

The answer here is trimethoprim. Trimethoprim and co-trimoxazole, anti-folate antibiotics, should be avoided concurrently with methotrexate due to the risk of bone marrow aplasia. This reaction is due to the additive folate depletion when the medications are combined. Fatal pancytopenia and megaloblastic anaemia have occurred. Penicillins may reduce the excretion of methotrexate, and there are no interactions reported in the BNF with nitrofurantoin or cefalexin.

Question 6

A 25-year-old man with a history of Crohn’s disease presents asking for advice. He currently takes methotrexate and asks if it is alright for him and his partner to try for a baby.

What is the most appropriate advice?

• He should wait at least 6 months after stopping treatment
• He should wait at least 12 months after stopping treatment
• He should have semen analysis 8 weeks after stopping treatment prior to trying to conceive
• There are no limitations on male patients
• He should wait at least 3 months and his partner should take folic 5 mg od

Answer 6

Patients using methotrexate require effective contraception during and for at least 6 months after treatment in men or women