Preventable Adverse Drug Reactions and the Risk of Forgotten Reactions

Preventable adverse drug reactions remain a persistent and underrecognised challenge in modern healthcare. A recent case identified through DrugCard’s literature monitoring highlights a critical issue in pharmacovigilance: patients are still being re-exposed to medications that previously caused adverse drug reactions.

This is not an isolated phenomenon. Evidence suggests that a significant proportion of hospital readmissions due to adverse drug reactions involve the same drug-reaction pair. These events are often linked to gaps in prescribing practices or incomplete patient history.

At the same time, real-world pharmacovigilance data show that patients with a known history of adverse drug reactions represent a distinct risk group – yet this information is not consistently translated into clinical decision-making.

Where the System Fails in Preventable Adverse Drug Reactions

So where does the system fail? Adverse drug reactions are documented – but not always accessible. Case reports are submitted – but not integrated into care pathways. Patients experience reactions – but are rarely empowered to track them.

For pharmacovigilance professionals, this raises an important question: Are we only detecting signals, or are we truly preventing harm?

Preventable Adverse Drug Reactions and Re-Exposure to the Same Drug

One of the most concerning patterns in pharmacovigilance is the repeated exposure of patients to the same drug that previously caused an adverse reaction. Studies show that a substantial proportion of hospital readmissions due to adverse drug reactions involve the same drug-reaction combination. In many cases, these events could have been avoided.

Preventable adverse drug reactions often occur not because the risk is unknown, but because the information is not available at the point of care. This disconnect between knowledge and action represents a critical limitation of current pharmacovigilance systems.

Why Preventable Adverse Drug Reactions Still Occur

There is no single cause behind preventable adverse drug reactions. Instead, they arise from a combination of systemic and human factors.

Lack of accessible ADR history

Adverse drug reactions may be documented in safety databases or case reports, but this information is not always integrated into clinical workflows. As a result, healthcare professionals may unknowingly prescribe a drug that previously caused harm.

Fragmented healthcare systems

Patients often receive care from multiple providers. Without centralised and interoperable systems, critical safety information can be lost between visits, institutions, or even countries.

Patient awareness and recall

Patients play a key role in preventing repeated exposure. However, many do not remember the exact name of the medication or may not recognise the importance of reporting past adverse drug reactions.

Limited integration of pharmacovigilance data

Pharmacovigilance systems are highly effective at detecting and analysing safety signals. However, their integration into real-time clinical decision-making remains limited.

The Role of Pharmacovigilance in Preventing Repeat Harm

Preventable adverse drug reactions highlight a gap between signal detection and risk prevention. Pharmacovigilance professionals are at the centre of this gap. While they collect and assess valuable safety data, this information does not always translate into actionable insights at the point of care. To reduce preventable adverse drug reactions, pharmacovigilance must evolve beyond data collection. It should also focus on:

• Supporting systems that make ADR history easily accessible
• Promoting communication between healthcare providers
• Encouraging patient education and engagement
• Contributing to risk minimisation strategies that extend into clinical practice

From Case Detection to Risk Prevention

The case identified through literature monitoring serves as a reminder that detecting adverse drug reactions is not enough. Even when a reaction is known, documented, and analysed, patients may still be re-exposed to the same risk.

This suggests that the true challenge is not only identifying adverse drug reactions, but ensuring that this knowledge is retained and applied in clinical practice. Preventable adverse drug reactions are, by definition, avoidable. Yet they continue to occur because safety information is not consistently translated into action.

This case was not identified in routine clinical practice, but was identified through systematic literature monitoring, highlighting the importance of continuous signal detection beyond traditional reporting systems.

How to Reduce Preventable Adverse Drug Reactions

Addressing preventable adverse drug reactions requires a structured, multi-level approach that connects pharmacovigilance with real-world clinical practice. To reduce preventable adverse drug reactions, healthcare systems need stronger documentation processes that integrate ADR history directly into prescribing workflows, ensuring that critical safety information is visible at the point of care.

In addition, better data sharing across healthcare systems is essential to prevent information loss when patients move between providers. Preventable adverse drug reactions can also be reduced through patient-centred strategies that encourage individuals to track, remember, and report their past reactions more effectively.

At the same time, closer collaboration between pharmacovigilance and clinical practice is needed so that safety insights are not only collected but also actively used in decision-making.

In many cases, a simple question could make a difference: Have you experienced a reaction to this medication before?

Conclusion

Preventable adverse drug reactions are not just isolated clinical errors. They reflect broader system-level gaps in how safety information is collected, shared, and used.

For pharmacovigilance professionals, this is an opportunity to rethink impact. Beyond identifying risks, the goal should be to ensure that known risks do not result in repeated harm. Because in drug safety, what is forgotten can be just as dangerous as what is unknown.