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Safe Prescribing Quiz
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Which of the following medicines used for rheumatological conditions must be prescribed once weekly rather than daily to prevent serious toxicity?
- A Hydroxychloroquine You picked ✕
- B Leflunomide You picked ✕
- C Methotrexate You picked ✓
- D Azathioprine You picked ✕
- E Sulfasalazine You picked ✕
Correct!
Incorrect
The answer is C: Methotrexate
Explanation
Why C is correct
See Right Time. Option C is correct because methotrexate for autoimmune conditions such as rheumatoid arthritis is taken once a week, not daily. Methotrexate blocks the use of folate (a vitamin needed to make DNA), so it damages fast-dividing cells and can severely suppress the bone marrow, inflame the lining of the mouth and gut, and injure the liver and lungs. A daily dose therefore delivers seven times the intended weekly exposure. The MHRA and the BNF warn that inadvertent daily dosing instead of weekly has caused fatal overdoses, which is why new measures were introduced in 2020. This is the Right Time principle of safe prescribing: some drugs have specific time-dependent rules, and getting the frequency wrong can be as dangerous as getting the dose wrong. Write the full dosing day (for example, once WEEKLY on Mondays) on the prescription, agree the day with the patient, and make sure the patient knows that it is not a daily tablet.
- Drug: methotrexate for autoimmune conditions.
- Frequency: once a week, never daily.
- Principle: Right Time, as daily dosing has caused fatal overdoses.
Why the other options are incorrect
- A. Hydroxychloroquine: Hydroxychloroquine is used for rheumatoid arthritis and systemic lupus erythematosus, but in these conditions it is normally taken once or twice daily. Weekly dosing is used for malaria prophylaxis, which is a different indication, so it is not the rheumatological drug with the weekly safety rule. Your answer
- B. Leflunomide: Leflunomide is an oral disease-modifying drug used in rheumatoid arthritis and psoriatic arthritis, and it is taken once daily. It has no weekly prescribing rule, so it does not carry the specific weekly safety warning asked about here. Your answer
- D. Azathioprine: Azathioprine is an immunosuppressant used in several autoimmune rheumatological conditions, usually taken once or twice daily with regular blood monitoring. It is not prescribed once weekly for rheumatological disease, so it is not the medicine with the weekly dosing safety rule. Your answer
- E. Sulfasalazine: Sulfasalazine is a disease-modifying drug used in rheumatoid arthritis and inflammatory bowel disease, normally taken twice daily with food. It has no weekly prescribing rule, and taking it only weekly would not provide continuous disease control. Your answer
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More questions from this set. Start the quiz to answer them and see each explanation.
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1
Which requirement applies to a paper NHS prescription (FP10) for a prescription-only medicine issued in the community?
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2
A 19-year-old woman needs treatment for a bacterial infection and oral amoxicillin is being considered. She says she is allergic to penicillin but cannot remember what happened. What is the most appropriate next step before prescribing?
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