Electronic prescribing: errors due to multiple causes.

It takes longer to create an elec- tronic prescription than to handwrite a prescription, and the extra workload varies depending on the software used. Bugs, crashes, unreliable access and sluggish response times can cause errors and data loss. Screens that contain too much or poorly displayed information can gen- erate errors through cognitive overload. Information entered in a free-text field, often in order to bypass a problem, can result in conflicting instructions that are missed by inbuilt safeguards. The propagation of default values in input fields can cause errors, including dosing errors, administration errors and premature treatment cessation. Medication errors and adverse effects attributed to electronic pre- scribing can result from a combination of factors. These contributory factors include: incomplete knowledge of how the software works; unclear display of information on the screen; confusing presentation of successive prescrip- tions in the patient's medication history; failure to verify the patient's iden- tity; having several patients' records open at the same time; prescribing from a location other than the unit in which the patient is hospitalised; inappropriate configuration of the drug database; rushed implementation of healthcare information technology; and communication failures between different programmes. There is a tendency to place too much faith in electronic prescribing. Health professionals must carefully check the prescriptions generated and recorded, and the patient's various recent prescriptions. They must take into account situations at increased risk of error, such as prescribing from a remote location that precludes veri- fication with the patient.