Hesitancy to start new medications is often experienced by people due to concerns regarding possible side effects. A list of side effects of a certain medication is usually compiled following an analysis of clinical trial outcomes involving the medication. However, it is important to note that the side effects observed in clinical trials are not always reflected in clinical practice. Consequently, healthcare professionals use their discretion when prescribing, taking into account their clinical experience, patient’s medical and family history, current signs and symptoms, and effectiveness of the medication. Some factors that may affect the accuracy of data with respect to the side effects as reported by clinical trials are discussed below.
1. Size and design of clinical trials
Size and design of a clinical trial are very important in determining the quality of the trial. Usually, the higher the number of participants, the more credible is the outcome. Additionally, the design of the trial also plays an important role. Most clinical trials conducted to evaluate the safety and effectiveness of new treatments for a particular medical condition are randomized in their design.
For more information visit: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3196997/.
2. Confounding factors
The main objective of the randomization of clinical trials is to place participants into control and test groups evenly based on certain characteristics, such as weight, age, and gender, etc. These characteristics are referred to as confounding factors. Although with randomization, the confounding factors are minimized to a great extent they may not be completely eliminated. For example, a mental health medication, aripiprazole, is linked with heart rate/rhythm abnormalities. However, the side effect has mostly been observed in patients with pre-existing heart disease or risk factors for heart disease (such as obesity and smoking), and those who are currently taking other medications that may cause heart rhythm abnormalities.
For more information visit: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3503514/#:~:text=A%20confounder%20cannot%20be%20an,and%20coronary%20heart%20disease%20(Fig.
3. Causation is not established
Most clinical trials are designed to evaluate the safety and effectiveness of a certain medication. Oftentimes, the side effects reported by patients are documented as it is and causation is not determined. For example, if we look at the mental health medication we discussed above, some side effects associated with it are headache, cold symptoms, nausea, stomach discomfort, and cough. Now, although these side effects were reported by participants during the study, the causal relationship with the mental health medication was not established. Moreover, the occurrence of these side effects was similar in participants receiving placebo (pill without any medicinal effect).
For more information visit: https://www.ncbi.nlm.nih.gov/books/NBK236283/
4. Subjectivity of data
Different clinical trials employ different techniques for questioning the participants with regard to side effects. It is currently not established if open-ended questions (such as how are you feeling?) are better than asking specific questions (such as do you experience headache, pain, nausea, and/or blurred vision?). However, what is important to note is that everyone has a different response to a certain medication and their perception of side effects may also vary greatly. Since researchers are mostly reliant on participants’ presentation of side effects, the outcome of a trial can be affected by the subjectivity of data.
For more information visit: https://www.jpsmjournal.com/article/S0885-3924(99)00093-7/fulltext
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.MR000039.pub2/full
