Erratum and a further Clarification
1. The pharmacy where I bought the bootleg, fake Cialis was on Soi 22 not Soi 23 as I originally posted. The pills, the box, the packaging, everything about them looked real, but they were fake. They were poison. Pill for pill, I could not tell them apart from the real ones I had purchased in a Costco Pharmacy, USA. I am glad I did not mix the two lots together.
2. As far as I am aware, all the large, airconditioned, national chain Pharmacies in BKK require a prescription in order to purchase Cialis or Viagra. That is too bad and the main reason I make the bulk of my purchases in Jakarta and Manila. That said, I have made small purchases at Charoen Pharmacy on Sukhumvit between Soi 4 and Soi 2. In my experience, they are a very reliable provider of name brand and generic medications (not just ED meds) with very good prices. Someone else pointed out that, "they do massive sales business and rely on their reputation for quality."
The only thing I do not like about them is their store has no air conditioning, thus all their medications are stored at BKK room temperature. But I always look to buy product from them with the most time left until expiration and I have never been disappointed with the quality of the meds they have sold me. BM's, This is the place to make your purchases if you are not venturing on to Manila or Jakarta.