# Emergency prescribing for the PSA Source: PassthePSA, PSA revision notes URL: https://passthepsa.com/psa-revision/emergency-prescribing/ Updated: 2026-10-01 Topic: UK Prescribing Safety Assessment (PSA) revision Short answer: Emergency prescribing in the PSA mostly means a once-only prescription for a time-critical drug: adrenaline 500 micrograms IM (1 in 1000) for adult anaphylaxis, a benzodiazepine first line in status epilepticus, naloxone for opioid overdose, and oxygen written as a target saturation range of 94-98%, or 88-92% when hypercapnic failure is a risk. ## What goes in the once-only section of the chart? The once-only section is for a single dose to be given at a stated time, such as an emergency drug, a premedication or a loading dose. - Write the drug, dose in a unit, route and the date and time, and sign it. - Do not write an emergency drug as a regular prescription. A repeating prescription for adrenaline or naloxone is an error, and the exam instruction line tells you which section the marks are on. - As-required drugs have their own section and need a maximum dose or frequency. - In a real emergency, give the drug immediately and document afterwards. ## How is anaphylaxis treated? Adrenaline is the first-line drug in anaphylaxis, given intramuscularly and as early as possible. - Adult dose: adrenaline 500 micrograms IM, which is 0.5 mL of 1 in 1000 (1 mg/mL), into the anterolateral thigh. It can be repeated after about 5 minutes if there is no improvement. - Children are dosed by age band: use the BNF for Children or the Resuscitation Council UK chart. - Do not confuse 1 in 1000 IM with 1 in 10 000, which is a different preparation used IV by experienced staff in specific circumstances. - Give high-flow oxygen, and IV fluids for hypotension. Antihistamines and corticosteroids are not part of initial treatment. ## What are the first-line drugs in other emergencies? Emergency | First-line principle | Exam trap --- | --- | --- Acute severe asthma | Oxygen, nebulised salbutamol, ipratropium and a systemic corticosteroid; IV magnesium on senior advice | Do not delay steroids; check the BNF for doses Hypoglycaemia | Fast-acting oral carbohydrate if able to swallow; IV glucose or IM glucagon (1 mg) if not | Recheck glucose and give longer-acting carbohydrate; glucagon works poorly in starvation and liver disease Status epilepticus | IV lorazepam (4 mg in an adult); buccal midazolam or rectal diazepam if no IV access | A benzodiazepine comes first; phenytoin, levetiracetam or valproate are second line Acute coronary syndrome | Aspirin 300 mg loading dose, analgesia and treatment per local pathway | Give oxygen only if saturation is below 94% Acute pulmonary oedema | Sit upright, oxygen only if hypoxic, IV furosemide for fluid overload. Nitrates are not routine: use GTN only for ongoing ischaemia or severe hypertension, and avoid if hypotensive | Opioids and nitrates are not routine; follow NICE and local guidance Hyperkalaemia with ECG changes | IV calcium gluconate, then insulin with glucose and nebulised salbutamol | Calcium protects the heart but does not lower potassium; stop contributing drugs Opioid overdose | Naloxone, titrated to respiratory rate | Naloxone wears off sooner than many opioids, so monitor and repeat ## What are the first-hour principles for sepsis? In suspected sepsis, speed matters: high-risk patients need IV antibiotics and fluids within the first hour, and others follow the NICE risk-stratified timings. - The Sepsis Six: give oxygen, take blood cultures, give IV antibiotics, give IV fluids, measure lactate and monitor urine output. - NICE guidance advises a crystalloid bolus of 500 mL over less than 15 minutes in adults who are hypotensive or have a high lactate, with reassessment after each bolus. - Choose the antibiotic from the local sepsis guideline and the allergy history. Check the BNF. ## How is oxygen prescribed as a drug? Oxygen is a drug and should be prescribed with a target saturation range, not a fixed flow rate. Patient group | Target saturation | Note --- | --- | --- Most acutely ill patients | 94-98% | Do not give routinely if saturation is already in range At risk of hypercapnic respiratory failure, such as COPD | 88-92% | Use controlled oxygen, such as a 24% or 28% Venturi mask, until blood gases are known In cardiac arrest, anaphylaxis and major trauma, give high-flow oxygen initially. Titrate down to the target range once the patient stabilises. ## How are IV fluids prescribed? A fluid prescription names the fluid, the volume and the rate or duration. - Resuscitation: NICE guidance advises a 500 mL crystalloid bolus over less than 15 minutes, then reassessment. - Routine maintenance: roughly 25-30 mL/kg/day of water with about 1 mmol/kg/day each of sodium, potassium and chloride, and 50-100 g/day of glucose. - Check electrolytes before adding potassium, and reduce rates in heart failure and renal impairment. Note: Confirm in the BNF: doses and volumes here are stable teaching figures, not instructions. Confirm every dose, route and age band in the BNF and local guidance. ## Check yourself - What is the adult IM adrenaline dose in anaphylaxis, and what volume of 1 in 1000 is it? - What is first-line in status epilepticus? - Why must naloxone be monitored after the first dose? - What target saturation applies to a patient with COPD? - Which drug protects the heart in hyperkalaemia but does not lower potassium? - What loading dose of aspirin is given in ACS? - What are the Sepsis Six? - Which chart section is used for an emergency drug? ## Questions people ask Q: What is the adrenaline dose for adult anaphylaxis? A: 500 micrograms IM, which is 0.5 mL of 1 in 1000 (1 mg/mL), repeated after about 5 minutes if there is no improvement. Children are dosed by age band. Q: What target oxygen saturation should I prescribe? A: Aim for 94-98% in most acutely ill patients and 88-92% in those at risk of hypercapnic respiratory failure, such as people with COPD. Q: What is first-line for status epilepticus? A: A benzodiazepine, usually IV lorazepam. If there is no IV access, buccal midazolam or rectal diazepam is used. Second-line drugs follow if seizures continue. Q: Why can naloxone need repeating? A: Its effect is shorter than that of many opioids, so respiratory depression can return. Patients need monitoring and may need repeat doses or an infusion. ## Related notes - High-risk medicines for the PSA: https://passthepsa.com/psa-revision/high-risk-medicines/ - How to write a safe prescription: https://passthepsa.com/psa-revision/prescribing-safely/ - PSA calculation skills: doses, rates and units: https://passthepsa.com/psa-revision/calculations/ - Antibiotic prescribing for the PSA: https://passthepsa.com/psa-revision/antibiotics/ Sources: BNF; Resuscitation Council UK anaphylaxis guidance; British Thoracic Society oxygen guideline; NICE guidance on sepsis, intravenous fluids and epilepsies; UK Kidney Association hyperkalaemia guideline. Exam-revision notes, not patient-specific advice; the BNF is the authority. More: https://passthepsa.com/psa-revision/ (all notes), https://passthepsa.com/psa/ (exam guide), https://passthepsa.com/ (practice questions).