Understanding commonly used drugs and their interactions is vital for the safety of patients and the efficacy of these medicines. Non-prescribers and prescribers alike need to be aware when to query and/or stop medications if the patient is unwell and why this needs to be done. Although stopping and restarting a medication may seem daunting and possibly confusing for patients and clinicians alike, there must be awareness around the medications that can cause problems in the very sick patient. There are many resources available for general practice nurses (GPNs) to check. This article gives a brief summary of some of the most common pitfalls and how to avoid these with useful resources at the end.