Table 1.

Examples of types of prescribing alerts with descriptions and hierarchy of alerts

		Types of alerts
Hierarchy of alerts		Drug contraindication	Drug-drug interaction	Dose-range checking
Low-level (minor severity)	Description	Used when the presence of a coded contraindication (usually disease state) means that the use of the medicine could be harmful	Used for combinations of medicines which in certain circumstances could cause harm	Use of a drug probably outside clinically acceptable or usual limits for dose quantity or timing, but risk of harm not considered high
	Specific system example	Atorvastatin (a cholesterol-lowering drug) should be used caution with renal impairment due to the risk of side-effects of muscle inflammation	The use of atenolol and diuretics (both drugs used in hypertension) together may cause low blood pressure	Daily dose warning limit for beclometasone nose drops is 18 drops
Intermediate (moderate severity)	Description	Used when the presence of a coded contraindication (usually disease state) means that the use of the medicine may be potentially hazardous and requires avoidance or other precautions	Used for potentially hazardous interactions of drugs which require avoidance or other special cautions	Use of a drug outside clinically acceptable limits for dose quantity or timing based upon the likelihood of severe harm with that dose the usual dosing of that drug
	Specific system example	Aspirin should not be given in the presence of gastrointestinal ulceration due to the risk of bleeding	Using methotrexate and ciclosporin (both immunosuppresants) together can lead to toxicity	The infusion rate of vancomycin (antibiotic) is limited to 600 mg/h; a higher rate may cause ‘red man’ syndrome or hypotension
High-level messages (hard stop)	Description	Used when the presence of a coded contraindication (usually disease state) prohibits the prescription due to risk of harm	Used for combinations of drugs that should be avoided in all situations	Use of a drug significantly outside clinically acceptable limits for dose quantity or timing based upon the likelihood of serious harm with that dose
	Specific system example	Abciximab (a potent drug used to prevent thrombosis in cardiac patients) is not prescribable to patients with brain tumours due to high risk of bleeding	The antibiotic erythromycin and the antipsychotic pimozide are disallowed in combination due to risk of potentially fatal cardiac rhythm abnormality	Amphotericin (Abelcetan) – an antifungal drug – > 6 mg/kg is associated with severe toxicity at any higher weight-based doses