Chapter 15: Medicines optimization: ensuring quality and safety
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Source: Adapted from Beijnen and Schellens ([22]), Riedl and Casillas ([301]).
Source: Adapted from Mirakian et al. ([214]) with permission of John Wiley & Sons.
Source: Adapted from Mirakian et al. ([214]) with permission of John Wiley & Sons.Source: Adapted from Mirakian et al. ([214]) with permission of John Wiley & Sons.
Key principles for administration of medicines
Patient identification
When administering a medicine, the nurse must be certain of the identity of the patient to whom the medicine is to be administered (RPS [317]), and it is recommended that at least two patient identifiers should be used (e.g. check name, hospital number and date of birth) (Joint Commission [148]). To avoid misidentification of patients, staff should check the patient's identity using an identification wristband, which should meet the nationally required standards for wristbands (NPSA [266]).
Electronic prescribing and medicines administration (EPMA) systems provide further safeguards where both the patient's identity and the medicine to be administered are confirmed through the use of a bar code reader or similar. If available, these should be used according to local policies and procedures.
Patient misidentification can occur at any stage of a patient's journey (Joint Commission [147]), with incidents relating to medication administration not always captured as they may not always be recognized (Paparella [278]). Not identifying the patient correctly can result in the administration of the wrong drug or dose, and can sometimes be fatal (Schulmeister [328]). The patient's prescription chart should be taken to the bedside to ensure verification against two patient identifiers (e.g. patient name, date of birth and/or hospital number) (Gunningberg et al. [111], Joint Commission [147]).
Allergy status
Accurate and up‐to‐date allergy information is important in reducing medicine‐related harm to patients. The patient's allergy status must be current at all times. This should include identifying positively where a patient does not have an allergy. If it is not possible to determine whether a patient has an allergy, this should be documented as ‘unable to ascertain’, and the actual allergy status should be documented as soon as the information is available (NICE [244]). It is the responsibility of all healthcare professionals involved in the patient's care to update and document any identified allergies, hypersensitivities, anaphylaxis or drug intolerances (Jevon [145], Shelton and Shivnan [331]).
Allergic reactions are immune mediated and can be classified as in Table 15.4. There are many risk factors that increase the likelihood of an allergic reaction. These can be split into those that are specific to the patient and those that are specific to the drug. The patient‐related factors and drug‐related factors are listed in Boxes 15.1 and 15.2 respectively.
Table 15.4 Types of allergic reactions
| Type of reaction | Result of reaction | Example of reaction |
|---|---|---|
| Type I: IgE‐mediated reactions | Urticaria, angio‐oedema, anaphylaxis and bronchospasm | Anaphylaxis from beta‐lactam antibiotic |
| Type II: IgG/M‐mediated cytotoxic reactions | Anaemia, cytopenia and thrombocytopenia | Haemolytic anaemia from penicillin |
| Type III: IgG/M‐mediated immune complexes (also known as ‘serum sickness’) | Vasculitis, lymphadenopathy, fever, arthropathy and rashes | Serum sickness from antithymocyte globulin |
| Type IV: Delayed hypersensitivity reactions | Dermatitis, bullous exanthema, maculopapular and pustular xanthemata | Contact dermatitis from topical antihistamine |
| IgE, immunoglobulin type E; IgG/M, immunoglobulin type G/M. |
Box 15.1
Allergic reactions: patient‐related risk factors
- Immune status: previous reaction to the same or related compound.
- Age: younger adults are more likely to have an allergic reaction than infants or the elderly.
- Gender: women are more likely than men to suffer skin reactions.
- Genetic: atopic predisposition is more likely to result in a severe reaction, and genetic polymorphisms (e.g. G6PD deficiency, slow acetylators) may predispose a person to drug hypersensitivity.
- Concomitant disease: viral infections such as HIV and herpes are associated with an increased risk of allergic reactions. Cystic fibrosis is associated with an increased risk of allergic reactions to antibiotics, which is thought to be due to prolonged use in this group of patients.
Box 15.2
Allergic reactions: drug‐related risk factors
- Drug chemistry: some drugs are more likely to cause drug reactions than others. These are high‐molecular‐weight compounds, such as insulin. Additionally, drugs that bind to proteins called haptens (e.g. beta‐lactam antibiotics) form complexes that can cause an immune response.
- Route of administration: the topical route is most likely to cause an allergic reaction, with the oral route being the least likely. The intramuscular route is more likely to cause an allergic reaction than the intravenous route.
- Dose: a large single dose is less likely to cause a reaction than prolonged or frequent doses.
Although the incidence of true allergic drug reactions is low, the potential morbidity and mortality related to these reactions can be high, so it is important that drug allergies are accurately diagnosed and treated. The first step towards an accurate diagnosis is a detailed history (Mirakian et al. [214]). Guidance on what information should be collated and accurately recorded is detailed in the British Society for Allergy and Clinical Immunology's drug allergy guidelines (Mirakian et al. [214]) and in NICE ([244]) guidance, and include the following:
-
Detailed description of reaction:
- symptom sequence and duration
- treatment provided
- outcome.
- Timing of symptoms in relation to drug administration.
-
Has the patient had the suspected drug before this course of treatment?
- How long had the drug(s) been taken before onset of reaction?
- When was/were the drug(s) stopped?
- What was the effect?
- Witness description (from patient, relative or doctor).
- Is there a photograph of the reaction?
- Illness for which suspected drug was being taken – that is, underlying illness (this may be the cause of the symptoms, rather than the drug).
- List of all drugs taken at the time of the reaction (including regular medication, over‐the‐counter medications and ‘alternative’ remedies).
-
Previous history:
- other drug reactions
- other allergies
- other illnesses.
Advice on the management of a drug reaction is provided in Box 15.3. In some cases desensitization may be considered, but this is rarely indicated.
Box 15.3
Treatment of acute drug reactions
An acute drug reaction must be treated promptly and appropriately:
- Stop the suspected drug.
- Treat the reaction.
- Identify and avoid potential cross‐reacting drugs.
- Record precise details of the reaction and its treatment.
- Identify a safe alternative. In some cases this may not be possible so, where the case is less severe, it may be decided to continue with the medication with suppression of the symptoms with, for example, a corticosteroid and an antihistamine.
See also ‘Complications’ within ‘Intravenous injections and infusions’ below.
Following an allergic reaction, it is extremely important that the patient is given information regarding what substances they should avoid. This information must be recorded clearly in the patient's medical records, including paper and electronic records. All inpatients with an allergy should have this indicated by wearing a red‐coloured identity band (NHSI [238]). The allergic drug reaction should also be reported using the Yellow Card Scheme (Mirakian et al. [214]) (see ‘Adverse drug reactions’ below).
Prior to administering any medication, the nurse must confirm the patient's allergy status and where necessary document any changes.
Medication checks
The nurse must know the therapeutic uses of the medicine to be administered as well as its normal dosage, side‐effects, precautions and contraindications. If the nurse has concerns regarding the prescription or the prescription is not clear, the prescriber or pharmacist must be contacted. If weight and/or height are required for calculation of the dose, a recent height and weight must have been used.
Calculating the required dose is vital as any miscalculation of medication dosage represents a potential threat to both patient safety and clinical effectiveness (Harvey et al. [121]). It is important for nurses to acquire and maintain mathematical competency in practice in order to prevent medication errors (Brady et al. [29]), although there is insufficient evidence to conclude that medication errors can be linked to nurses’ poor calculation skills (Sherriff et al. [333], Wright [378]). Incorporating computer‐based competency within practice and practice simulation assessments has been shown to be highly effective in medication calculation training for nurses (Sabin et al. [320]), but more research is required (Stolic [341]).
To ensure the patient receives the intended treatment, the following checks must be performed:
- correct medicine and formulation selected
- correct dose prepared
- medicine within expiry date
- correct route, administration time and rate (if applicable).
If a delivery device is required, the correct device must be used (e.g. a vascular access device for intravenous therapy or an epidural catheter for epidural drug administration).
Record of administration
The nurse must document a clear, accurate and immediate record of all medicines administered, intentionally withheld or refused by the patient, ensuring all written entries and signatures are clear and legible. If any medication is withheld or refused by a patient, the reasons must be documented, and, where appropriate, the prescriber and/or multiprofessional team must be informed (RPS [317]).
Single or double checking of medicines
Medicines can be prepared and administered by a single qualified nurse or by two nurses (known as double checking). There are certain times when double or second checking is required. It is recommended that for the administration of CDs, a secondary signature is required. Additionally, where the administration of a medicine requires complex calculations, it is deemed good practice for a second practitioner (a registered professional) to check the calculation independently in order to minimize the risk of error (RPS [317]).
Single checking can ensure greater accountability, increase attentiveness to procedures, encourage updating of drug knowledge and better use nursing time (Cross et al. [50]). In contrast, double checking can dilute individual responsibility and contribute to increased medication errors (Armitage [11]). More research is required, however, especially in paediatric management (Conroy et al. [42]).
An alternative is the use of independent double checking. This is when two nurses check a drug independently of each other. In the setting up of ambulatory chemotherapy pumps, a study showed that the use of independent double checking showed no significantly statistical difference in dose, rate or documentation errors when compared with traditional double checking, but it did show a reduction in errors related to patient identification (Savage and Tripp [323]).
Those nurses who wish or need to have their administration supervised should retain the right to do so until such a time as all parties agree that the requested level of proficiency has been achieved. The nurse checking the medicine must be able to justify any action taken and be accountable for the action taken. This is in keeping with the principles of The Code (NMC [257]).
Delegation of medicines administration
If a registered nurse or nursing associate delegates any aspect of the administration of a medicinal product to a patient, their carer or a care assistant, they remain accountable for the delegatee's actions and non‐actions and any omissions that occur (NMC [257]). As a registered professional, they are accountable for all aspects of their practice, which includes delegating a task or accepting a task delegated to them. When delegating, the registered nurse or nursing associate must ensure that the task is within the individual's scope of competence, that the individual fully understands the instructions, and that they are adequately supervised and supported (NMC [257]). Student nurses must never administer or supply medicinal products without direct supervision, and both the student and the registered nurse must sign the medication chart or document the administration in the notes (NMC [257]).
Additional factors to consider
Drug interactions
Consideration should also be given to potential interactions between concomitant drugs and/or food. These interactions can result in an increased effect (causing toxicity) or a decreased effect (resulting in decreased efficacy of the drug). Drug interactions can be divided into pharmacokinetic (Table 15.5) and pharmacodynamic (Table 15.6) interactions.
Table 15.5 Types of pharmacokinetic interaction
| Type of interaction | Interaction caused by | Example of when to consider in clinical practice |
|---|---|---|
| Drug absorption interactions |
| In cases of tetracycline absorption interaction with milk, bisphosphonate use, etc. ( Medicines Complete [195]) |
| Drug distribution interactions |
| Therapeutic drug monitoring, as drugs that can be displaced in this way (e.g. phenytoin) can appear subtherapeutic when monitored but doses would not need to be increased ( Medicines Complete [195]) |
| Drug metabolism interactions |
| Grapefruit juice can inhibit the cytochrome P450 isoenzyme CYP3A4, thus reducing the metabolism of calcium channel blockers ( Medicines Complete [195]) |
| Drug excretion interactions |
| Probenecid and penicillin compete for the same active transport systems in the renal tubules; as a result, probenecid reduces the excretion of penicillin, which can lead to penicillin toxicity ( Medicines Complete [195]) |
Table 15.6 Types of pharmacodynamic interaction
| Type of interaction | Interaction caused by | Example of when to consider in clinical practice |
|---|---|---|
| Additive or synergistic interactions |
| Opioids with benzodiazepines can cause increased drowsiness ( Medicines Complete [195]) |
| Antagonistic or opposing interactions |
| Vitamin K and warfarin result in the effects of the anticoagulant being opposed ( Medicines Complete [195]) |
Herbal and complementary medicines have increasingly been used in the UK over recent years and as a result there has been an increase in the reporting of interactions between these agents and conventional drugs. Some of the most common herbal interactions are those containing St John's wort, a popular herbal product used as an antidepressant. Concomitant use should be avoided with, for example, antiepileptics, antivirals and warfarin.
Interactions can also occur between drugs and food. Food can have an effect on drugs by changing gastrointestinal motility or by binding to drugs while in transit in the gastrointestinal tract. An example of interactions between food and a drug can be seen with monoamine oxidase inhibitors (MAOIs) and tyramine‐containing foods (such as mature and aged cheeses, yeast or meat extracts, pickled fish, salami, broad bean pods and heavy red wines). Tyramine is a chemical present in certain foods that are rich in protein and can interact with MAOIs. As procarbazine has mild MAOI properties, taking both together can result in a hypertensive reaction, which can cause symptoms of raised blood pressure, headache, pounding heart, neck stiffness, sweating, flushing and vomiting. Patients taking MAOIs should therefore be advised to avoid tyramine‐rich foods (Medicines Complete [195]). The British National Formulary has a comprehensive list of drug interactions and the potential clinical consequences (BNF [25]). Concerns over actual drug interactions and their management should be discussed with a pharmacist.
Adverse drug reactions
Although drugs are used to diagnose, prevent or treat disease, no drug is administered without risk. It is important when choosing a drug treatment that consideration is given to the balance between clinical effect and undesired effects.
The World Health Organization's (WHO) definition of adverse drug reactions (ADRs) is ‘harmful, unintended reactions to medicines that occur at doses normally used for treatment’ (WHO [371], p.1). ADRs can be classified as type A or type B reactions. Type A (‘augmented’) reactions are considered to be exaggerations of the medicine's normal effect when given at the usual dose. This category includes unwanted reactions that are predictable from the drug's pharmacology and are usually dose dependent (e.g. respiratory depression with opioids and bleeding with warfarin). In many instances this type of unwanted effect is reversible and the problem can often be dealt with by reducing the dose (Rang et al. [294]).
Type B (‘bizarre or idiosyncratic’) reactions are effects that are not pharmacologically predictable and can include hypersensitivity reactions (e.g. anaphylaxis with beta‐lactam antibiotics). These are not related to the pharmacological action of the drug and are not dose related, and therefore cannot be controlled by dose reduction. Type A reactions are more common than type B but type B reactions tend to cause higher rates of serious illness and mortality.
The WHO ([371]) states that ‘ADRs are among the leading causes of death in many countries’. Drug‐related adverse events, including ADRs, have been reported to be among the leading causes of morbidity and mortality (de Vries [55], Lazarou et al. [171]). ADRs occur in both outpatients and inpatients (Kongkaew et al. [158], Krähenbühl‐Melcher et al. [160], Leendertse et al. [172]). In a meta‐analysis conducted in 2002, an average of 4.9% of hospital admissions were associated with ADRs, with the rate ranging between 0.2% and 41.3% in individual studies (Beijer and de Blaey [21]). This meta‐analysis considered that 28.9% of the ADR‐related hospitalizations were preventable. Of inpatients, 10.9% are estimated to experience an ADR during hospitalization (Lazarou et al. [171]). A more recent meta‐analysis has shown that among adult outpatients, 2% had ADRs, of which 52% were preventable. Among inpatients, 1.6% had ADRs, of which 45% were preventable (Hakkarainen et al. [113]).
According to the WHO ([371]), the cost of ADRs, including hospitalizations, surgery and lost productivity, exceeds the cost of medicines in some countries. Work in the US a number of years ago (Rodriguez‐Monguio et al. [305]) showed that significant costs may be avoided if drug‐related adverse events, including ADRs, are prevented.
Although the effect of a drug cannot always be predicted, it is important that when a drug is given to a patient, the risk of harm is minimized by ensuring that the prescribed medicine is of good quality, safe, effective and used by the right patient in the right dose at the right time. Consideration should always be given to predisposing factors that drugs or a patient may have that could increase the risk of ADRs, including:
Preventing and detecting adverse effects from medicines is termed ‘pharmacovigilance’. It is an important factor for all healthcare professionals to consider in order to identify potential new hazards relating to medicines and prevent harm to patients (MHRA [207]).
Although medicines are widely tested within clinical trials before they become commercially available, trials do not provide information about how different patient populations may respond to the medicines. The only way for this information to be collected is through careful patient monitoring and further collection of data through post‐marketing surveillance. In the UK this information is collected through the Yellow Card Scheme, which is run by the MHRA and the Commission on Human Medicines. The scheme is used to collect information from both healthcare professionals and patients about suspected ADRs with prescribed medicines, over‐the‐counter medicines and herbal medicines. Yellow Cards can be completed via the MHRA website (https://yellowcard.mhra.gov.uk) or by completing the paper card found in the British National Formulary.
