At the price of a weeks pills for $1000, the biggest change would be a bigger divide between the rich and the poor.
Let's say a person currently can happily work 8 hours, live 8 hours, and sleep 8 hours. Your proposal would remove the sleep 8 hours, freeing up the time for other activities, both social and money earning. My numbers are very rough, since many people work either more or less than 8 hours a day.
Lets look at earnings: Median household income in the US is $$51,939 per year (2013 numbers), or almost exactly $1000 per week. This means that half the households in the US earn less than $1000 per week, and many of these households already have people working more than 8 hours a day.
So for people in these homes, working an extra 8 hours would be losing money relative to the pill. For anyone taking home less than $$1000 a week, the pill would be a rare luxury. Some people would use it for important occasions, but they couldn't afford it regularly or they would go bankrupt. This is roughly half the population, although it could be a lot more if people are earning $1000 a week, but working more 8 hour days.
Then there's the middle ground. If you can earn more than $1000 by working during your extra 8 sleep-free hours, the pill might be worth while. You would be earning enough to afford pay for the pill, plus you'd have a little extra time for either earning an additional income, or for other pursuits including socializing with friends and family or furthering an education. But for a lot of people who have to work all their extra hours just to afford the pill, it wouldn't be worth while unless they really love their job. Otherwise, they are forced to spend extra time doing something they don't want, and get nothing out of it.
Now lets take the wealthy: If you bring home more than $$500 in an 8 hour workday, you can afford the pill by working just two nights a week. That means you have lots of extra time to do whatever you want, and even if you hate your job, the extra time might be worthwhile for the sake of the extra free time. If you can bring in more than $1000 per day, you can reasonably afford the pill for your entire family without, assuming 2-3 kids and a spouse.
What are the social implications of all this?
The most obvious consequence of all this is that the income gap between the wealthy and poor will increase. The wealthy will have more time to earn money and more time to educate themselves to further increase their earnings. They will be able to afford pills for their children, who will be able to spend more time studying in school, and especially in college.
The wealthy will also be living on a different schedule than everyone else. They will most often socialize with others who take the pill, further isolating themselves from contact with the poor. They will want to be able to walk into a restaurant or store at 3 am, and get the same service as they could at 3 pm.
The higher demand for 24 hour service would be detrimental to the poor group, who would take most of the new late night service jobs, but would still need to sleep 8 hours a day. Since school would probably still be held during the day, except for a few expensive private schools for the pilled up children of the elite, this would mean a whole lot of parents who see less of their children, and who struggle to get enough sleep during the day.
For the middle group, who can sometimes afford the pill, but have jobs where they aren't working directly for the wealthy, less would change. Some jobs would shift to the night-time to accomodate the pill takers, but a lot of the office work would remain during daylight hours, since that's when the kids are in school, and only the wealthiest can afford the pill for the kids. Nights would be a time to run errands and socialize with adult friends while the kids are asleep.
In short, the biggest consequence of the pill would be stratification of society. Further consequences would flow from that. With a cheaper pill, the results would be different.