01Principles and purposeThe professional or clinical skill and the decisions it supports.
A prescription is a clinical decision expressed as an instruction. Safe prescribing therefore begins before choosing a drug and continues after it is supplied. The prescriber needs an explanation for the problem, an outcome that matters to the person and a reasonable expectation that the proposed intervention can deliver it. A raised measurement alone does not determine a medicine: its reliability, the underlying diagnosis, competing conditions and consequences of treatment all matter. An accurate electronic order can still encode a poor decision. Conversely, a sensible treatment choice can become dangerous when an ambiguous strength or frequency reaches the person administering it.
Three linked questions organise the work: is treatment needed, is this treatment appropriate now, and how will its benefit and harm be recognised? These questions apply equally to starting, continuing, withholding and restarting medicines. Repeats deserve active thought because physiology and priorities change while the prescription may remain identical. GMC prescribing guidance requires adequate information and assessment, an appropriate consultation method and meaningful dialogue. Use national recommendations to identify the treatment strategy and the exact product information to check formulation-specific instructions; a licence and a guideline answer different questions. Where evidence, licensing or local arrangements differ, document the decision and secure the expertise necessary to carry it out.
Key points
- Confirm the person, therapeutic objective, medicine exposure and allergy history before selecting a treatment.
- An apparently usual dose can be unsafe after dehydration, renal deterioration, weight loss or an interacting prescription.
- Write the medicine, formulation, route, dose, frequency, indication and intended duration so the administrator need not infer them.
- For as-required medicines, specify the minimum interval and maximum daily dose, including overlapping combination products.
- Ask the person to explain the plan back, including what improvement and warning symptoms should prompt action.
- Name the person responsible for results and review; sending a test request does not complete monitoring.
02Situations and prioritiesThe context, relevant information and actions that matter most.
Convert the presenting concern into a treatment target: relieving pain enough to mobilise, controlling a defined infection, or reducing a particular future event. Distinguish a patient request from an established indication. If the diagnosis remains uncertain, ask whether treatment could obscure an important alternative or whether observation and reassessment would provide a safer route to an answer.
A medicine tolerated for years can become hazardous within days. Reduced intake may change fluid balance; acute illness may reduce clearance; confusion may prevent correct administration. Treat recent deterioration as a reason to re-evaluate medicines even when the dose is unchanged. Baseline information should describe the patient now, not merely the last annual review.
Look particularly carefully at decimal points, micrograms, insulin units, concentrated liquids, modified-release preparations and unusual intervals. These are places where a correct mental plan can turn into the wrong delivered dose. Select the precise formulation from the prescribing system and inspect the final order rather than trusting a familiar search result or pre-populated frequency.
A person may understand an instruction yet be unable to execute it because of swallowing difficulty, poor vision, an inaccessible container or a schedule incompatible with work. Explore actual use without accusation. Changing packaging, timing or formulation may restore treatment effectiveness more safely than increasing a dose that is only intermittently taken.
03Assessment and interpretationHow to gather information, assess the situation and recognise uncertainty.
Consider the information, its meaning and its limitations before deciding what follows.
- 01
Identity and medicines interview - Why
- Establish whose prescription is being written and what exposure already exists.
- Interpretation and limitations
- Use reliable identifiers and ask about prescribed, purchased, borrowed and recently stopped products. Record the active ingredient in combination remedies. An electronic repeat list shows intended prescribing, while the interview reveals administration; discrepancies require resolution rather than choosing whichever account is easiest to copy.
- 02
Allergy and prior reaction assessment - Why
- Determine whether previous harm changes the current treatment choice.
- Interpretation and limitations
- Record the culprit, reaction, timing, severity and subsequent tolerated exposures. Nausea after a medicine is different from airway swelling, although both may affect acceptability. An empty allergy field is missing information rather than proof that no allergy exists. Clarify uncertainty before exposing the person to a potentially implicated medicine.
- 03
Dose-relevant measurements - Why
- Identify physiological factors that could alter the appropriate regimen.
- Interpretation and limitations
- Measure or verify weight where dosing depends on it and inspect current kidney function, relevant liver tests, pregnancy possibility and other drug-specific baseline observations. For medicines whose guidance specifies creatinine clearance, do not silently substitute the laboratory eGFR. In rapidly changing renal function, either estimate may lag behind the clinical situation.
- 04
Prescription and supply verification - Why
- Check that the chosen treatment can be given exactly as intended.
- Interpretation and limitations
- Compare the order with the indication and selected formulation, recalculate any conversion, and inspect the available strength. Independently check high-risk calculations according to the clinical setting. Confirm quantity against intended duration. A mathematically correct millilitre dose is still unsafe if the dispensed concentration differs from the one used in the calculation.
04Worked approachesCases with ordered reasoning, an action and a check of the outcome.
01Worked caseResolve an unsafe analgesic requestA 76-year-old with three days of vomiting, reduced urine output and a painful wrist requests repeat oral ibuprofen. She takes ramipril and a diuretic, has not checked her blood pressure and cannot recall her last kidney result.+
- 1Identify the immediate problem: dehydration and reduced urine output could represent acute kidney injury. Ask about collapse, confusion, severe pain, trauma and systemic illness, and arrange prompt face-to-face assessment rather than treating the request as a routine repeat transaction.
- 2Reconstruct the medicine exposure, including the last ibuprofen dose and any purchased analgesics. The interaction risk comes from the combination of impaired perfusion, altered renal autoregulation and an NSAID; an old normal kidney result cannot establish present safety.
- 3Decide against authorising ibuprofen at this assessment. Evaluate the wrist and hydration, obtain relevant observations and renal tests, and arrange an alternative pain plan. Review the other medicines individually in the context of the acute illness, documenting any temporary withholding and criteria for restarting.
- 4Explain the decision in terms of the current illness and treatment goal. Provide a written record of exactly which medicines are being changed, whom to contact if intake or urine output worsens and when the pain and hydration will be reassessed.
- 5Verify closure: establish who will review the blood results and confirm that the prescription system reflects the plan. At follow-up, reassess pain, renal recovery and the continuing indication before any restart; a temporary hold must not disappear into an indefinite omission.
02Prescription constructionTurn the decision into an executable orderTreatment has been selected after assessment, and the prescription must be safe for dispensing and administration.+
- 1Enter the generic medicine name unless a clinically important formulation or brand requirement applies. State the strength and pharmaceutical form; immediate-release and modified-release versions can have different dosing schedules and must not be treated as interchangeable search results.
- 2Write the dose with an unambiguous unit and the administration route. Use a leading zero for a dose below one and avoid unnecessary trailing zeros. Spell out micrograms and units; a hurried reader should not have to distinguish similar abbreviations to avoid a large error.
- 3Specify frequency and intended course or review point. For an as-required order, add the symptom, interval and daily maximum. Include a maximum across scheduled and rescue doses when they contain the same active ingredient.
- 4Calculate a supply sufficient for the intended plan, then check the final prescription against the patient record. Ensure administration instructions, monitoring requirements and relevant equipment accompany the medicine; a liquid may require an oral syringe rather than a household spoon.
03Shared planMake starting and reviewing one decisionA person agrees to a new regular medicine but is uncertain about possible adverse effects and future reviews.+
- 1Describe the expected benefit in terms the person can recognise and the likely time course. Separate common tolerability problems from rare symptoms that need urgent action, and agree how to seek advice without waiting for a routine appointment.
- 2Check understanding by asking how the medicine will fit into an ordinary day. Invite questions about cost, transport, beliefs and practical barriers without assuming that apparent agreement means the treatment will be taken.
- 3Set a review date tied to the medicine and the clinical problem. Specify which symptoms, observations or laboratory results will determine continuation, titration or stopping, and arrange a mechanism for acting on abnormal results.
- 4Communicate material changes to the professionals continuing care. If prescribing is outside usual licensing, establish the evidential basis and relevant expertise, explain what is material to the person and document why the chosen preparation and regimen meet their needs.
05Relevant medicines and safetySpecific regimens and precautions when the skill involves prescribing.
Paracetamol: example of a complete as-required order
For a suitable adult: 500 mg to 1 g orally every 4–6 hours when needed for pain, maximum four doses and 4 g in 24 hours; reassess persistent pain rather than renewing automatically.Check all combination products and lower-weight, malnourished, hepatic or renal risk before selecting an individual maximum; a standard adult ceiling is not an instruction to reach it.
06Feedback, follow-up and evidenceReview outcomes, seek feedback and identify what to improve.
- Compare the agreed outcome with baseline. A lower pain score accompanied by inability to stay awake is not satisfactory benefit, and a laboratory target achieved at the cost of recurrent falls may require a different plan.
- Review tolerability and actual administration before escalation. Ask specifically about missed doses and self-adjustments so that an apparent failure of drug effect is not confused with failure of delivery.
- Ensure investigation results reach an accountable clinician. Document the action taken, advice given and next check; acknowledgement of a result and appropriate clinical response are separate steps.
- At every transition, record starts, stops, dose changes and the reasons behind them. Check whether a temporary inpatient prescription should continue at home and whether a withheld long-term medicine needs deliberate reconsideration.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
Dose is multidimensional
A regimen includes amount, route, interval and duration. Two orders with the same daily milligram total may produce different peaks or exposure when formulation and timing differ. Think about the delivered pattern as well as the arithmetic total.
Authority and evidence
National guidance supports a treatment strategy; an SmPC describes a particular licensed product. A recommendation may involve use outside the licence. Identify that distinction explicitly instead of attributing every familiar regimen to a manufacturer or assuming a licence alone determines clinical priority.
Remote clinical assessment
The consultation medium must permit the information needed for the decision. If examination, observations or reliable medication confirmation are necessary, arrange them. Increasing confidence in a diagnosis cannot compensate for a missing measurement that determines dose safety.
Responsibility remains active
A pharmacist review, electronic alert or specialist recommendation contributes expertise but does not remove the prescriber’s responsibility to understand the relevant decision. Clarify incomplete advice and agree ownership when several teams participate in initiation and monitoring.
08Common pitfallsFrequent interpretation and management errors.
- 01
Copying a discharge dose without checking indication, duration and recent physiology can perpetuate an inpatient decision after its context has changed.
- 02
Recording only tablets per dose conceals the strength and can create a large error when the patient receives a different tablet size.
- 03
Providing a long list of possible adverse effects without a clear action plan leaves the person uncertain about which symptoms require help.
- 04
Treating a repeat request as proof of benefit misses silent toxicity, practical non-adherence and an indication that has already resolved.