A third option could be 'Flowers for Algernon' by Daniel Keyes. Although not exactly about pills in the same sense, the main character undergoes a medical procedure that changes his intelligence. It shares the theme of a character experiencing a significant change through some form of medical intervention, which could be related to the concept in the 'novel take the pills book'.
One book that might be similar is 'Brave New World' by Aldous Huxley. In this novel, there are substances that are used to control the population and keep them in a certain state of mind, somewhat like the idea of pills in the 'novel take the pills book'.
Another similar book could be 'The Giver' by Lois Lowry. Here, the main character is given pills for 'the stirrings', which is a way of suppressing emotions. It has that element of pills being used in a way that affects the characters' state of being, much like what might be in the 'novel take the pills book'.