Are expected medication side effects counted as adverse drug events that cause harm?
Yes. Some medications have frequent and expected side effects. For example, narcotics commonly cause constipation. This known side effect can be prevented, or at least mitigated. Therefore, it should be classified as minor harm, which is Category E on the National Coordinating Council for Medication Error Reporting and Prevention (NCC MERP) Index for Categorizing Medication Errors. Whether or not an ADE causes harm does not depend on whether or not it is expected. Narcotic-induced constipation may seem minor to a clinician but not to a patient.
