Doxycycline for Threat Memory Consolidation

The study medication was doxycycline, brand name Vibramycin (Pfizer). A GMP-licensed pharmacy (Kantonsapotheke Zürich) manufactured, blinded, and randomized the study medication separately for males and females; mannitol was used as placebo. Randomization code was broken after the last participant completed the study, and after all data were checked for consistency. The study dose of 200 mg is the smallest antibiotic dose recommended by the manufacturer and the same dose that yielded a 60% reduction in threat memory consolidation in a previous report (Bach et al., 2018a (link)).