A 23 year old IV drug user comes to your clinic with

A 23 year old IV drug user comes to your clinic with complaints of missed periods.. You do a pregnancy test which comes out positive. Later, you do a ELISA which comes out positive for HIV.. this is confirmed witha western blot.. You decide to put her on AZT prophylaxis but you are not convinced that she will adhere.. what is the alternative drug that can be used here to cut down the risk of HIV transmission in her newborn?