Is it possible to lose weight with a dramatic drop in calorie intake?

i used to put down 2700 calories a day with the occasional exercise (because of sports/ enough to feel good, but still enough to burn to lose weight)...but recently i am not able to exercise anymore due to some personal reason...so i decided to diet by taking in only 1500 calories a day and drinking a lot of water...is that healthy in the long run?...i still do some quick weightlifting (15 mins every other day) ...i know the fact that once your body burns fat it starts to burn muscle when malnourished..but i also take vitamins as well....just wondering if its worth doing that for awhile to help lose weight.