I went there around 20h30 and they were closed. Went to a a pharmacy practically on the other side of Soi Buakaow next to a 7-11. They sold me Apcalis, a generic of Cialis made in India for only 250 bahts per box of four. Best price yet in Thailand where the usual price is 400 B. Of course, you can get them for 6$ a box in Phnom Penh.