Hospital Pharmacy · Short notes

Drug Distribution Systems: Short Notes & Cheat Sheet

Floor stock, individual prescription, unit dose and automated systems, controlled drugs on wards, and preventing medication errors.

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Short notes

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Ways medicines reach the ward

Hospitals usually combine systems: unit dose for routine doses and a small floor stock for emergencies.

The main systems

Floor (ward) stock: drugs are kept on the ward in bulk. Access is quick, but errors, wastage, pilferage and expired stock are common and the pharmacist cannot review each order.
Individual prescription order: each patient's supply is dispensed against their own prescription. The pharmacist reviews every order, but it is slower and needs more staff.
Combination system: individual prescriptions with a limited floor stock of common and emergency drugs. It is the most widely used in practice.
Unit dose system: each dose is packed and labelled ready to give, usually for no more than 24 hours. It has the lowest error rate and least waste, but high set-up cost.
Automated dispensing cabinets on wards release drugs only to authorised staff against a verified order and keep an electronic record.

Special arrangements

Emergency (crash) carts hold resuscitation drugs and must be checked and resealed after every use.
A night cabinet or on-call pharmacist covers supplies outside working hours.
Controlled drugs are kept in a locked cupboard and recorded in a register with running balances. Doses are witnessed and signed by two staff.
Satellite (decentralised) pharmacies serve high-use areas such as ICU, theatres and oncology.

Medication safety

Errors can happen at prescribing, transcribing, dispensing, administration or monitoring.
The 'rights' of administration: right patient, drug, dose, route and time, plus right documentation, reason, form and response.
Look-alike, sound-alike (LASA) drugs are separated on shelves and labelled with tall-man lettering (hydrOXYzine vs hydrALAZINE).
High-alert medicines cause the most harm when errors occur: insulin, heparin and anticoagulants, opioids, concentrated potassium chloride, chemotherapy and neuromuscular blockers.
Concentrated potassium chloride ampoules should be removed from general ward stock.

Cheat sheet

High-yield facts in one place. Cover the right-hand column and test yourself.

Systems compared

System	Main advantage · drawback
Floor stock	Immediate access · errors, waste, pilferage
Individual prescription	Pharmacist review · slow, labour-intensive
Combination	Balance of both · still some ward stock
Unit dose	Fewest errors, least waste · costly to set up
Automated cabinets	Controlled access, records · expensive

High-alert medicines

Medicine	Main risk
Insulin	Hypoglycaemia (unit errors)
Heparin, warfarin	Bleeding
Opioids	Respiratory depression
Concentrated KCl	Fatal arrhythmia
Chemotherapy	Severe toxicity
Neuromuscular blockers	Respiratory arrest

Memory aids

Unit dose = 24 hours, ready to give: Each dose is individually packed and labelled, usually a day's supply at a time.

Exam traps

Unit dose, not floor stock, gives the lowest medication error rate.
Floor stock suits emergency drugs and cheap, high-use items, not the whole formulary.
Never write 'U' for units; it has been misread as a zero.
Controlled drug balances are recorded after every transaction, not just at stock-take.

Revised? Now test yourself.

Attempt the Drug Distribution Systems MCQs while the notes are fresh. Anything you get wrong is saved to your incorrect list for the next revision round.