The author doesn't seem to make the connection, but the Mallinckrodt Corporation's cocaine hydrochloride can also be found at your favorite neighborhood retailers as a white powder for ~$80 / gram. It's 'regular' cocaine.
And more specifically, Levamisole is becoming something of a hot topic as a dangerous, but desirable for its ability to pass most purity tests. http://www.time.com/time/health/article/0,8599,1955112,00.ht... is one overview. The DEA journal Microgram has covered it a few times as well.
Cocaine hydrochloride IS cocaine, the fine white powder drug. It is distinct from free base cocaine, commonly known as 'crack', which is made by stripping the hydrochloride ion using a strong alkali. Crack is popular because the free base form is more pharmacologically active, meaning you get more bang for the same price, or alternatively, the same bang for a lower price.
I don't know if CVS or Walgreens would have a reason to stock in at the local store, but they could likely get it from their regular distribution. Yes, a medical doctor can prescribe this but it takes considerable extra paperwork (and receives DEA scrutiny). It would likely be more common in a hospital setting, usually as one ingredient in a compound.
