Paracetamol works mainly in the central nervous system to reduce pain signals and fever. Naproxen is a Non-Steroidal Anti-Inflammatory Drug (NSAID) that works by blocking chemicals called prostaglandins that cause pain and inflammation at the site of an injury. Because they target pain through different pathways, their effects can be additive without interfering with how the body processes each drug.
This is a companion discussion topic for the original article at https://de.patient.info/medication-interactions/paracetamol-and-naproxen-interaction