The Short Version
This claim is false. Every major health and environmental authority — including the EPA, CDC, FDA, and MedlinePlus — identifies drug take-back programs as the safest disposal method for prescription medications, not flushing. Flushing is only recommended for a small subset of high-risk drugs (primarily opioids) on the FDA's "Flush List," and only when take-back options are unavailable. For the vast majority of prescriptions, flushing is actively discouraged because it contaminates waterways and drinking water.