My first language is Finnish, which has a very straightforward correspondence between spelling and pronunciation.
I would divide the drug names into four categories based on how they sound:
Obviously a substance: Amantidine, Sildenafil
Generic fantasy names / pronounceable strings with no meaning: Azafen, Clédial, Cymbalta, Desyrel, Edronax, Luvox
Could be Tolkienian, but it's spelled wrong: Sintamil
Could be Tolkienian, but the final syllable is wrong: Elronon, Eskalith, Nardil
Additionally, the two Tolkien characters I had to guess were both kings of Gondor: Minalcar and Narmacil. Their names are in Quenya, while the commonly used names for elves etc. are in Sindarin, which sounds different.