Week 2: Safe Prescribing and Pharmacovigilance Flashcards
Outline Reason’s model of error causation
The general model of error generation can be broken down into three primary components introduced here: Latent Conditions; Error Producing Conditions; Active Failures. A further component in the system is a set of defences. Ideally these defences should be inherent both within the system and the individual.
outline the “Swiss Cheese Model”
If the layers of defences have inherent weaknesses, or the system is incompetently conceived with inadequate defences for finding error, they may pass completely through all the layers to cause a serious adverse event.
What are the two types of adverse drug reaction?
Type A - Causally related to drug pharmacology, exaggerated response – common
Type B –Unrelated to known pharmacology, idiosyncratic response - rare
What is a Prescribing Error?
The term prescribing error incorporates irrational prescribing, inappropriate prescribing, under prescribing, over prescribing and errors in writing the prescription
Factors affecting the Quality of Prescribing – Patient Related Factors
• Increased use of medicines generally
• More rapid throughput and increasing numbers of patients
• More sicker / older patients with: o Co-morbidities (renal/hepatic)
o Multiple drugs (polypharmacy)
o Increased risk of adverse effects
• Increasing complexity of medical care • Increased specialisation
Factors affecting the Quality of Prescribing – Doctor Related Factors
• Workplace Culture
o Feeling there is no room for error
o Being expected to be perfect from day 1 o Being afraid to ask!!!
• Experience from Medical School
o Level of teaching
o Level of examining
o Lack of Pharmacology training
o Too many students !??!?
• Shift Work and Reduced Hours o Lower exposure to teaching etc
o Working alone more often
o Less ward teaching and feedback o Poorer morale
o Lack of continuity of care
• Prescribing On Call
o Rarely know patient
o Routine- “boring jobs” o Re-write drug charts o Prescribe fluids
o Prescribe new unfamiliar drugs
o Prescribe old drugs in absence of results
Factors affecting the Quality of Prescribing – Drug Related Factors
• New drug developments
• Extending medicines into new areas
• More complex medicines being used in less complex ways
• Clinical evidence is usually with drug used in isolation in:
o Selected relatively healthier patients and/or young volunteers initially
• Side Effects and Interactions come to light only during post marketing surveillance
• Blind adherence to guidelines leads to prescription where contraindications or serious interactions exists
Factors Affecting Prescribing Errors - Medicines
• Vast numbers of new drugs
• Clinical evidence is usually with drug used in isolation in: o Selected relatively healthier patients
o and/or young volunteers initially
• Some side effects come to light only during post marketing surveillance
• Blind adherence to guidelines leads to prescription where contraindications or serious interactions exists
• New drug developments, extending medicines into new areas
• Increased use of medicines generally
what are the two types of mistakes in the classification of errors?
- Knowledge Based Errors (through lack of knowledge)
Giving Penicillin with establishing allergy status
Being unaware of the interaction between warfarin & erythromycin - Rule Based Errors (using a bad rule or misapplying a good rule) Injecting diclofenac into the lateral thigh rather than the buttock Prescribing oral treatment for a patient with dysphagia
what are the three what are types of skills based errors in the classification of errors?
- Action Based Errors (Slips)
• Picking up a packet containing diazepam from the pharmacy shelf when
intending to pick up digoxin
• Writing up amiodarone instead of aminophylline while being distracted
3a. Technical Errors (Slips)
• Putting the wrong amount of potassium chloride into an infusion bag • Writing illegibly so that ‘Panadol’ is dispensed instead of Priadel - Memory Based Errors (Lapses)
• Giving penicillin know that a patient is allergic
• Forgetting to specify a maximum daily dose for an ‘as required’ medicine
Define violations.
Violations differ from slips, lapses and mistakes because they are deliberate illegal actions, i.e. doing something knowing it to be against the rules (ie. deliberate failing to follow proper procedures). They may be either benevolent or malevolent.
Good Prescribing Guidelines
• The Drug Name and Preparation should be written clearly and not abbreviated, using approved
names only (except where there is a clinical reason to use a brand name)
• The Dose and Frequency should be stated including a minimum dose interval for as required
medications
• The Strength should be stated by the prescriber. In particular, strength of liquid preparations should be clearly stated (e.g. 125 mg/5 mL).
• The unnecessary use of decimal points should be avoided, e.g. 3 mg, not 3.0 mg.
• When decimals are unavoidable a zero should be written in front of the decimal point, e.g. 0.5 mL, not .5 mL.
• Use of the decimal point is acceptable to express a range, e.g. 0.5 to 1 g.
• Quantities
• Quantities of 1 gram or more should be written as 1 g
• Quantities less than 1 gram should be written in milligrams, e.g. 500 mg, not 0.5 g
• Quantities less than 1 mg should be written in micrograms, e.g. 100 micrograms, not 0.1 mg
• ‘Units’, ‘micrograms’ and ‘nanograms’ must not be abbreviated
• Directions should preferably be in English without abbreviation, it is recognised that some Latin abbreviations are used (for details see Latin abbreviations).
Legal Requirements – Prescription Only Medicines
Prescriptions or Patient Specific Directions should:
• Be written legibly in ink or otherwise so as to be indelible
• State the name and address of the patient
• State the address of the prescriber
• Give an indication of the type of prescriber
• Be signed in ink by the prescriber
• State the age and the date of birth of the patient
- this is a legal requirement for children under 12 years
Legal Requirements – Controlled Drugs
• Prescriptions for Controlled Drugs must be indelible, signed by the prescriber, be dated, and specify the prescriber’s address.
• The prescription must always state:
• the name and address of the patient
• the form (and where appropriate the strength) of the preparation;
• for liquids, the total volume in millilitres (in both words and figures) to be supplied;
• for dosage units, the number (in both words and figures) to be supplied;
• in any other case, the total quantity (in both words and figures) to be
supplied;
• the dose
• Note: A pharmacist is not allowed to dispense a Controlled Drug
unless all the information required by law is given on the prescription
What is an Adverse Drug Reaction (ADR)?
• WHO definition:
• Any response to a drug which is noxious and unintended and which occurs
at doses normally used in man for prophylaxis, diagnosis or therapy
• MHRA definition:
• Unwanted or harmful reaction experienced following the administration of a drug or combination of drugs under normal conditions of use and is suspected to be related to the drug
