Carrigan Neil, Raynor D K, Knapp Peter
School of Healthcare, University of Leeds, Leeds, UK.
Drug Saf. 2008;31(4):305-12. doi: 10.2165/00002018-200831040-00004.
One of the most important categories of information that patients want to know about the drug they are taking is the likelihood or probability of adverse effects. All patients should receive such information in the patient information leaflet that is supplied with all drugs. Anecdotal evidence suggests that most leaflets give little indication of the likelihood of adverse effects. The UK Medicines and Healthcare products Regulatory Agency (MHRA) suggests using a combination of words and numbers to convey this information. However, an EU guideline suggests using five verbal descriptors on a scale from common to rare, the use of which has been shown to lead to gross overestimation of the risk of adverse effects.
We assessed the leaflets supplied with the 50 most frequently prescribed drugs in England, to determine the extent to which the likelihood of adverse effects was described, and whether it met the requirements of the EU guidance and/or best practice. We examined both the method used to describe the likelihood of adverse effects, and the format of this information in the leaflet.
Twenty of the 50 leaflets (40%) gave no indication of the likelihood of adverse effects occurring. Six (12%) used the recommended EU terms and a further 20 (40%) used a wide range of other verbal descriptors. Only four leaflets (8%) provided any form of numerical indication of risk. Over half (52%) presented long lists of adverse effects in paragraphs of continuous text.
Patient need is not being met in terms of the provision of usable information about the likelihood of adverse effects. Most patients receive no information, whereas some are given verbal descriptors, both of which lead to overestimation of the risk. Very few of the patient information leaflets assessed used currently described best practice, i.e. to present verbal descriptions alongside numerical information in the form of natural frequencies, e.g. 'rare (affects less than 1 in 1000 people)'.
患者想要了解所服用药物的最重要信息类别之一是出现不良反应的可能性或概率。所有患者都应在随所有药物提供的患者信息手册中获取此类信息。轶事证据表明，大多数手册几乎没有提及不良反应的可能性。英国药品和医疗产品监管局（MHRA）建议使用文字和数字相结合的方式来传达此信息。然而，一项欧盟指南建议使用从常见到罕见的五个口头描述词，事实证明使用这些描述词会导致对不良反应风险的严重高估。
我们评估了英国最常处方的50种药物所附带的手册，以确定不良反应可能性的描述程度，以及其是否符合欧盟指南的要求和/或最佳实践。我们既研究了用于描述不良反应可能性的方法，也研究了手册中此信息的格式。
50份手册中有20份（40%）未提及不良反应发生的可能性。6份（12%）使用了欧盟推荐的术语，另有20份（40%）使用了广泛的其他口头描述词。只有4份手册（8%）提供了任何形式的风险数值指示。超过一半（52%）在连续文本段落中列出了长长的不良反应清单。
在提供关于不良反应可能性的可用信息方面，患者的需求未得到满足。大多数患者没有收到任何信息，而有些患者则得到了口头描述词，这两者都会导致对风险的高估。在所评估的患者信息手册中，很少有使用目前所描述的最佳实践，即以自然频率的形式同时呈现口头描述和数值信息，例如“罕见（影响不到千分之一的人）”。
