After the start of his management career, Epstein started taking stimulants, usually Preludin, which did not require a prescription at the time. Lennon, McCartney, Harrison, and Starr had also taken it since their days in Hamburg. Epstein explained his use of the drug as the only means of staying awake at night during numerous concert tours. In 1964 Peter Brown suspected that Epstein was taking too many pills, as he would often cough at parties, which Brown realised was Epstein's way of secretly putting pills into his mouth without anyone noticing. McCartney often met Epstein at late night clubs in London, and remembered that Epstein would often grind his jaws (possibly due to bruxism), once saying to him, "Ugghhh, the pills". Epstein also developed dependencies on the drug carbromal, a barbiturate-like sedative/hypnotic drug.