Serious side-effect warnings may be getting diluted on medication labels

Pharmaceuticals have a responsibility to tell doctors and users about any side-effects a drug might have.

But what if the list contains over 20 or 30 potential side-effects?

Even when just taking a paracetamol tablet we may be faced with a long list of potential reactions and potential problems of varying degrees. Are pharmaceutical companies doing this to cover their backs, or are they doing it to confuse the user by downplaying the risks?

Some are suggesting the latter…

Some scientific research suggests that being thrown a seemingly endless list of problems means the drug may seem less risky. This is a psychological phenomenon called the “dilution effect”.

Let’s take an extreme example that a drug only has one serious side effect:

• Kidney failure

Faced with such a clear and simple warning, anyone would probably think twice before taking the medicine.

Now, consider if the drug contains a long list of side effects including:

• Tiredness
• Nausea
• Itchiness
• Drowsiness
• Lack of appetite
• Dizziness
• Stomach pains
• Kidney failure
• Shortness of breath
• Headaches
• Migraines

There are more risks, but they’re mixed in with a lot of minor and temporary side-effects, meaning it could give some people the impression that the risks are less serious and / or less frequent or rare.

Researchers conducted a study with regards to this phenomenon and published the results. Using 3,000 participants, they conducted two experiments to see what people thought when given varying degrees of side-effects for the same drug.

In one experiment, 800 people listened to an advertisement for Cymbalta – an anti-depressant – where a long list of major and minor risks were read out. The same 800 people listened to an advertisement for the very same drug, but this time were only given the list of severe side-effects.

Although the first group of participants were told about more problems the drugs might have, the same group thought the drug was less risky than the drug with only serious side-effects. The study found that when faced with only serious side-effects, the consumer may think it will immediately cause them harm. However, when kidney failure or heart disease are listed alongside minor ‘discomforts’ like headaches and tiredness, the drug may not seem that risky overall.

Nonetheless, all risks should be communicated to the consumer so they know what they can expect. The severe yet less likely risks are important for the consumer to make an informed decision on balancing the major risks against the benefits. The less serious side-effects may be fairly common and may still impact the user’s day-to-day life, even temporarily. Manufacturers therefore should provide both, but perhaps separate them into two categories so as to limit any ‘diluting’.

This view is shared by many, including those involved in the study, who suggests that serious and minor side-effects need more distinction.