The idea is that this information is used to help prescribers make informed decisions when prescribing medication.
However, the truth is that the side effect information that prescribers receive depends on the source that they consult. In the UK, the most accessible source for medication information is the British National Formulary (BNF), but pharmacists in practice are more likely to use the Summary of Product Characteristics (SPC) or Meyler’s Side Effects of Drugs, a US-based source.
You might assume that all these standard texts have the same information, but that's not the case. For example, when it comes to Tramadol, there are different numbers of side effects listed in each source, and there is only a small overlap between the three sources. This lack of standardization makes it difficult to compare and interpret the information. Additionally, the terminology used for side effects varies across sources.
Even the frequency of side effects is not always reliable, as post-marketing data is categorized as "unknown frequency." Furthermore, there is no robust information about how the side effect profile changes over the long term. With some medications, there has been a significant increase in the number of reported side effects after they have been on the market for some time. This means that the side effect profile that prescribers have access to may not always be fully up-to-date or accurate.
Another challenge is that the side effect profile only looks at the drug in isolation and doesn't consider other medications a patient may be taking or other health conditions they may have. This means that the likelihood of a particular patient experiencing a particular side effect is difficult to predict.
What does this mean for prescribers? They need accurate, usable, and accessible information to make informed decisions about medication. This information may be needed when starting a medication or reviewing a patient's symptoms after they have been taking a medication for some time. Without full information, there is a risk that patients may be started on an inappropriate medication, or that their symptoms may be dismissed as being psychological.
To make a fully informed decision, prescribers would ideally have access to a full list of side effects in standardized terminology, information about which patients are more likely to experience side effects, the risk of cumulative side effects, what happens to the side effect profile after the drug trial period, and the real-life implications of co-morbidities.
Until then, pharmacists will continue to use the SPC and Meyler's Side Effects of Drugs, and prescribers will continue to work with partial information.
