A prescription can have the right medicine name and still be wrong for the patient in front of you. A new interacting treatment, a change in renal function, missing monitoring or an inappropriate instruction can alter what should happen before the next dose.
This prescribing quiz contains eight original, fictional reviews. The task is to identify the priority problem and say what you would stop, change or check. Some answers involve several linked steps, so do not force every case into a single-word category.
The examples are for clinicians and use UK medicines information and relevant professional guidance checked on 18 October 2026. They are not a substitute for checking the complete prescription, current product information and local pathway when treating an individual. Unless stated otherwise, the information supplied is current and the patient has not yet followed the new proposed instruction.
Eight prescription-review questions
1. The short antibiotic course
A 61-year-old takes simvastatin 40 mg at night. An infection specialist has selected clarithromycin for an infection after reviewing the available alternatives. The antibiotic is considered necessary, and the first dose has not yet been taken.
The prescription review says: "Continue usual medicines. Ask the patient to report muscle pain."
Your task: Is advice about symptoms sufficient? Identify the medicine that needs an explicit temporary plan, including what should happen after the antibiotic course.
2. A lower urinary infection with reduced renal function
A 74-year-old woman has dysuria and urinary frequency consistent with a lower UTI after assessment. She is systemically well, with no flank pain or features suggesting an upper urinary infection. Her stable, recently measured eGFR is 25 mL/min/1.73 m2.
The proposed prescription is a standard course of nitrofurantoin, without further consideration of the renal result.
Your task: Should the medicine be continued, given at a casually reduced dose or reconsidered? Explain whether the commonly discussed renal exception covers this patient.
3. Lithium, diarrhoea and an apparently reassuring old result
A 59-year-old taking maintenance lithium develops vomiting and diarrhoea. They are now unsteady and have a new coarse tremor. Their lithium level was within the intended range at a review last month.
The proposed response is: "Continue the usual dose and book a routine blood test next week. The last level was fine."
Your task: Identify the immediate medicine action and the assessment that should accompany it. Would you delay action solely to obtain a routine correctly timed monitoring sample?
4. The long-term steroid that is no longer wanted
A 48-year-old has taken prednisolone 10 mg daily for six months for an inflammatory condition. The treating team now considers the underlying disease controlled and agrees that ongoing glucocorticoid treatment may no longer be necessary.
The repeat-prescription instruction is changed to: "Stop tomorrow."
Your task: What is missing from this plan? Explain why a generic taper copied from another patient's prescription would not resolve the problem either.
5. A repeat reliever prescription without an anti-inflammatory plan
A 32-year-old with confirmed asthma requests another salbutamol inhaler. They report using it on several days each week. No inhaled corticosteroid or combination inhaler appears on the current list, and the patient confirms that none is being used.
They are not currently distressed or experiencing an acute severe episode. The proposed action is to issue a larger salbutamol quantity without a treatment review.
Your task: What treatment omission should be addressed? Which practical checks belong alongside a change in the prescription?
6. The renal number used for the dose
An 82-year-old woman weighing 45 kg has non-valvular atrial fibrillation. Anticoagulation has been judged appropriate following assessment. Renal function is stable, serum creatinine is 80 micromol/L, and the laboratory reports an eGFR of 62 mL/min/1.73 m2. There is no relevant hepatic contraindication or interacting medicine in this constructed case.
A new prescription proposes rivaroxaban 20 mg once daily, using the laboratory eGFR to select the dose.
Your task: Calculate the Cockcroft-Gault creatinine clearance using the female coefficient of 1.04 with the stated units. Does the standard atrial-fibrillation dose remain appropriate under the product information?
7. Gastroprotection that still needs the right medicine
A 70-year-old takes clopidogrel for an established vascular indication and has a previous ulcer bleed. The clinical team considers ongoing proton pump inhibitor gastroprotection appropriate. Their repeat list contains omeprazole.
The suggested response is: "Stop every proton pump inhibitor because none can be used with clopidogrel."
Your task: What should be changed, and what useful part of the existing treatment plan should be preserved?
8. The monitoring that an ECG does not replace
A 76-year-old takes amiodarone 200 mg daily under an agreed specialist plan. They are clinically stable. An ECG was performed recently, but the most recent thyroid and liver tests were 18 months ago. There is no documented arrangement for routine biochemical monitoring.
The repeat review says: "Monitoring complete: ECG checked."
Your task: What has been missed? Does the omission by itself justify abruptly stopping a clinically important antiarrhythmic without discussing the treatment plan?
Explained answers
1. Plan to withhold simvastatin during necessary clarithromycin treatment
Specialist Pharmacy Service guidance on macrolides and statins states that clarithromycin is contraindicated with simvastatin. Where clarithromycin is essential, simvastatin should be stopped for the course. The guidance also advises that a temporarily withheld statin can usually restart when the antibiotic course is finished.
Priority action: Prevent the concurrent course and document the temporary interruption and restart arrangement. Symptom advice remains useful, but does not make a contraindicated combination acceptable. Separating the administration times is not an adequate substitute.
The original review recognises a possible problem but leaves the exposure unchanged. The better plan is operationally clear: the patient, prescriber and dispensing team should know which medicine is paused and when it is intended to resume.
For a broader daily exercise in spotting what a plan needs, stat includes a separate "What would you change?" decision.
2. Reconsider nitrofurantoin: an eGFR of 25 is outside the limited exception
The MHRA's nitrofurantoin renal-function advice describes a general contraindication below an eGFR of 45. It allows cautious short-course use in selected patients with an eGFR of 30 to 44 when treating lower UTI with suspected or proven multidrug-resistant organisms and the benefits outweigh the risks.
Priority action: Do not treat that exception as covering an eGFR of 25. Select an appropriate alternative after considering local guidance, previous cultures, allergies and the patient's circumstances; an improvised dose reduction is not the answer.
The scenario specifies lower-tract symptoms so that the renal issue is the intended discriminator. Fever, systemic illness or flank pain would change the assessment and should not be squeezed into the same uncomplicated lower-UTI question. Nor does the existence of an exception make the general renal precaution irrelevant.
3. Withhold lithium and arrange urgent assessment for possible toxicity
New gastrointestinal symptoms, coarse tremor and unsteadiness in someone taking lithium require an urgent response. Specialist Pharmacy Service lithium-monitoring guidance advises withholding lithium when toxicity is suspected, obtaining an urgent lithium level and urea and electrolytes, and seeking specialist advice.
Priority action: Arrange urgent clinical assessment as well as the blood tests. Do not continue treatment unchanged while waiting for next week's routine monitoring appointment. The sample and urgent clinical response should not be delayed merely to reproduce the timing used for stable maintenance monitoring.
Last month's result describes last month's circumstances. It does not establish that the current dose remains appropriate during an intercurrent illness. Likewise, a level is one part of the assessment, not a reason to ignore a concerning clinical presentation.
The eventual decision about restarting or adjusting treatment needs the results, clinical course and appropriate specialist involvement; it should not be improvised from this short vignette.
4. Agree an individualised withdrawal plan rather than stopping abruptly
The joint European Society of Endocrinology and Endocrine Society guideline identifies adrenal-suppression risk with glucocorticoid exposure exceeding relevant duration and dose thresholds. It distinguishes a short course from long-term treatment and advises that withdrawal of long-term therapy should be considered when the underlying disease is controlled and steroids are no longer required.
Priority action: Replace the abrupt-stop instruction with a clinician-directed taper and assessment plan. This patient has taken more than a physiological prednisolone equivalent for substantially longer than a few weeks, so treating the prescription like a brief burst would be inappropriate.
A copied taper is not automatically correct. The plan must account for the disease, treatment history, symptoms during reduction and the approach to assessing recovery where relevant. Explain the agreed instructions and what to do if problems arise rather than simply editing a repeat-prescription line.
5. Review asthma control and introduce an appropriate ICS-containing strategy
The MHRA's SABA safety update highlights the risks of overuse and changes in prescribing guidance. Current BTS, NICE and SIGN guidance in NG245 does not support treating asthma with a SABA without concomitant inhaled corticosteroid treatment.
Priority action: Arrange a treatment review that addresses the missing anti-inflammatory component, rather than merely increasing the quantity of reliever supplied. Select the appropriate ICS-containing regimen through the current pathway and the patient's assessed needs.
Check symptoms, exacerbations, inhaler technique, adherence, preferences and the written action plan. A prescription change alone does not establish that the medicine will be used effectively. The absence of an acute severe episode allows this case to focus on ongoing treatment; acute deterioration would require its own immediate response.
6. Use creatinine clearance, then the indication-specific dose
For direct oral anticoagulants, the MHRA advises using Cockcroft-Gault creatinine clearance rather than substituting the laboratory eGFR. In this deliberately specified example, using the stated actual body weight and female coefficient:
Estimated CrCl = 1.04 x (140 - 82) x 45 / 80 = 33.93 mL/min.
The result is approximately 34 mL/min, not 62. These are different estimates with different units and purposes; the discrepancy is not resolved by choosing the more reassuring number.
The Xarelto product information recommends 15 mg once daily for stroke prevention in non-valvular atrial fibrillation at the relevant reduced creatinine-clearance range. The 15 mg and 20 mg tablets are taken with food. The proposed 20 mg regimen therefore needs correction in this case.
Do not export this dose automatically to another indication, such as the initial treatment of a DVT, or to unstable renal function. The calculation, indication, interactions and complete clinical assessment all matter.
7. Review the PPI choice without discarding indicated gastroprotection
Specialist Pharmacy Service guidance advises avoiding omeprazole and esomeprazole with clopidogrel and identifies alternatives such as lansoprazole, pantoprazole and rabeprazole where a PPI is needed. The MHRA's interaction advice likewise does not support treating every PPI as equivalent in this interaction.
Priority action: Choose an appropriate alternative PPI after reviewing the complete medication and clinical context. Do not stop the established antiplatelet indication or remove necessary gastroprotection merely because the current PPI is unsuitable.
The error is overgeneralisation. Recognising a drug interaction should lead to a specific correction, not a broader prohibition that introduces a different problem. The case states that gastroprotection remains indicated so that the question is about selecting it appropriately, not deciding whether any PPI is required.
8. Arrange overdue biochemical monitoring and establish responsibility
Specialist Pharmacy Service amiodarone guidance includes six-monthly thyroid function, liver function, renal function and electrolyte monitoring once treatment is stable, alongside an annual ECG. A recent ECG does not replace the biochemical checks.
Priority action: Arrange the overdue investigations, check for symptoms or other concerns and clarify which team owns the ongoing monitoring schedule. The MHRA's amiodarone safety reminder also emphasises monitoring and supervision.
An administrative gap does not by itself provide a complete reason to stop a clinically important antiarrhythmic abruptly. Discuss any treatment change with the responsible clinical team, particularly if symptoms or results suggest toxicity.
The lasting correction is not simply obtaining one set of blood tests today. It is ensuring that the patient does not return to the same undocumented monitoring gap after the results have been filed.
What the prescription review is actually testing
The eight problems are not all prescribing mistakes of the same kind. They include an interaction requiring a temporary interruption, a renal contraindication, possible toxicity, unsafe withdrawal, an omitted treatment component, use of the wrong renal estimate, an overbroad interaction response and incomplete monitoring.
For your own review, write two lines per case: what makes the current plan unsuitable, and what must happen before the problem is considered resolved. That second line is often where the practical work appears: documenting a restart, communicating a revised dose or assigning the next monitoring date.
A useful self-check is whether you could explain the correction to the patient without saying merely that "the computer flagged it". The record should contain the clinically relevant reason, not just a confirmation that an alert was acknowledged.
Use the quiz without turning it into a score of prescribing competence
For a team exercise, assign one case to each pair and ask for the priority action before showing the answer. A second pair can inspect whether the proposed correction creates a new omission, such as stopping gastroprotection without providing a suitable alternative.
These are suggested teaching activities, not a validated assessment instrument. A perfect score on eight described situations does not establish prescribing competence across medicines, patient groups or clinical settings.
The next useful learning step can be small: revisit the renal estimate required for one medicine, check the source behind one interaction or improve one monitoring arrangement. stat offers a separate daily management challenge, but today's edition is not guaranteed to contain a medication-review question on any of these topics.
Frequently asked questions
Should eGFR always be replaced with Cockcroft-Gault for every medicine?
No. The appropriate renal estimate depends on the medicine and its product information. Direct oral anticoagulants are an important situation in which MHRA guidance specifies creatinine clearance rather than relying on laboratory eGFR.
Does identifying a drug interaction always mean stopping both medicines?
No. The response depends on the exact interaction and clinical need. It may involve a temporary interruption, a suitable alternative, a dose change or additional assessment; the correction should preserve other necessary treatment where possible.
Can I use these examples as a prescribing checklist for an individual patient?
They are educational examples, not a complete patient-specific checklist. Actual prescribing requires the full history, medicine list, relevant investigations, current product information and an appropriate clinical assessment.