Prescribing in special situations

Renal/hepatic impairment, frailty, pregnancy/breastfeeding, children, weight, multimorbidity and route issues.

Pre-prescribing foundation: this module develops knowledge and judgement for formal prescribing education; it does not authorise prescribing.

• Recognise when renal or hepatic impairment changes medicine handling.
• Identify prescribing considerations in frailty and older age.
• Explain why pregnancy, breastfeeding and paediatrics require current specialist sources.
• Consider weight, swallowing, route and formulation issues.
• Avoid static rules where patient-specific source checking is required.

Special situations alter benefit, exposure, evidence quality and monitoring needs.

Frailty changes goals and vulnerability; chronological age alone is an incomplete guide.

Pregnancy and breastfeeding require balancing maternal and fetal/infant risks, including risk from untreated disease.

Children require age/weight-related dosing and paediatric sources; adult dose extrapolation is unsafe.

1. Define the clinical problem and whether prescribing is indicated.
2. Gather the patient-specific assessment and diagnostic information needed.
3. Check competence, professional authority and employer/service scope.
4. Compare reasonable options using current authoritative sources.
5. Agree the plan with the patient, including uncertainty and alternatives.
6. Prescribe accurately only when the decision is justified.
7. Document, monitor, review and safety-net.

Module emphasis: Use a current specialist source and patient-specific information rather than extrapolating a standard adult rule to a special population.

Scenario 1. A pregnant patient’s essential medicine is stopped without considering disease risk.

Reasoning prompt: Use a current specialist source and patient-specific information rather than extrapolating a standard adult rule to a special population.

Scenario 2. A child’s dose is copied from an adult regimen.

Reasoning prompt: Use a current specialist source and patient-specific information rather than extrapolating a standard adult rule to a special population.

Scenario 3. A frail patient with reduced renal function and low body weight receives a standard dose.

Reasoning prompt: Use a current specialist source and patient-specific information rather than extrapolating a standard adult rule to a special population.

• Pregnancy always means medicines should be stopped.
• Children are small adults.
• Frailty is the same as old age.

• What clinical problem am I trying to solve, and is prescribing indicated?
• What information is missing before a safe decision can be made?
• Is this within my current competence, professional authority and employer/service scope?
• Which current authoritative medicine or guideline source should I check?
• What patient-specific factors change benefit, harm, dose, route or monitoring?
• What will I document, monitor, review and safety-net?
• When should I seek supervision, pharmacy advice, specialist input or urgent escalation?

Optional reflection: Without entering identifiable patient or employer information, identify one capability you would need to strengthen before prescribing independently in this area.

• Special situations alter benefit, exposure, evidence quality and monitoring needs.
• Frailty changes goals and vulnerability; chronological age alone is an incomplete guide.
• Pregnancy and breastfeeding require balancing maternal and fetal/infant risks, including risk from untreated disease.
• Children require age/weight-related dosing and paediatric sources; adult dose extrapolation is unsafe.

Check current versions for time-sensitive decisions.

• BNF-01 - BNF / NICE: British National FormularyOpen official source
• BNFC-01 - BNF for Children / NICE: British National Formulary for ChildrenOpen official source
• RPS-01 - Royal Pharmaceutical Society: A Competency Framework for All Prescribers (2021)Open official source