Drug calculations
The RCSI reading list carries three tutorials on this: dose by weight, the basic formula, and volumes for injection. All three come down to one line: what you want, divided by what you have, times what it comes in. Here you do it with the chart on one side and the box, ampoule or bag on the other, the way it is at the medication round. Every medicine label is a presentation on the Irish register, so the strengths are the ones you will meet.
Two rules the assessor watches for. The unit is part of the answer: 0.25 is nothing until you say mL, and a volume is never a dose. And the arithmetic comes after the label check, not before: an out-of-date bag or a tablet that cannot be split is the answer, however neat the sum. NMBI (2020) 4.6 asks you to confirm every dose by calculation, and high-risk medicines named in local policy, anticoagulants and opioids among them, get an independent second check.
Sources: NMBI, Guidance for Registered Nurses and Midwives on Medication Administration (2020), 3.6 and 4.1 to 4.10; HSE Code of Practice for Healthcare Records Management: Abbreviations (2010), section 2; NMBI Practice Standards for Nurses and Midwives with Prescriptive Authority (2010), safe prescribing; HSE Medication Record adapted for the RCSI test, IV fluids page; the three calculation tutorials on the RCSI reading list; product strengths from the HPRA register and each product’s SmPC (26.09.2026). Feeds the drug chart and fluid balance trainers.