Intramuscular injection
PLAB 2 & PRES 3 · practical skills / pharmacology · easy · 8 minutes
Candidate brief
You are an FY2 doctor working in a GP surgery. Mrs Margaret Doyle, 67, has pernicious anaemia and attends every three months for her hydroxocobalamin (vitamin B12) injection, 1 mg intramuscularly. The prescription is on her chart and the injection is due today. Please prepare and give the injection, and explain to the patient what you are doing. Verbalise each drug check as you perform it.
What examiners look for
The drug check is the station. Drug, dose, route, time, expiry and — above all — patient identity, spoken aloud against the chart. Most serious injection errors in real practice are wrong-patient or wrong-drug errors caught (or not) in exactly these thirty seconds. Landmarking the deltoid is an anatomy exam in miniature: the safe zone sits about two to three fingerbreadths below the acromion, in the body of the deltoid. Too high and you are in the subacromial bursa (a recognised cause of shoulder injury related to vaccine administration); too low and the radial nerve is at risk as it winds around the humerus. Aspiration: candidates argue about this, so know the position. UK Green Book guidance for immunisation states aspiration is not necessary at recommended sites; many local policies for other IM medicines follow the same practice. What examiners want is a deliberate, stated technique — not a candidate who has never considered the question. Agree the site with the patient. A woman who carries shopping with her right arm and asks for the left is giving you free safety and satisfaction information. Refusing or ignoring preference without reason marks down the interpersonal score and, occasionally, matters clinically (lymphoedema, fistula arms, mastectomy sides — always ask why). Documentation for injectables includes batch number and expiry. Without them, a later adverse reaction cannot be traced to a batch — the same logic as blood products. It is the detail examiners use to separate routine candidates from careful ones. Close the loop on the condition, not just the injection: three-monthly attendance is also surveillance. Thirty seconds asking about pins and needles, tongue soreness and fatigue is how a recurring-injection station earns management marks too.
Guideline references
- https://www.gov.uk/government/publications/immunisation-procedures-the-green-book-chapter-4
- https://geekymedics.com/intramuscular-injection-im/
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