I too had trouble sleeping during chemo and tried Ambien, Ambien CR, Lunesta, and also resorted to Lortab. All the sleep aids seemed to lose their effectiveness after a while. Then my doctor recommend an over the counter sleep aid called Melatonin. I started out with a 1 mg pill and eventually cut it back to 0.5 mg (1/2 tablet), and it worked extremely well! I would highly recommend the Melatonin. Just experiment with your dosage to see what works for you. You might need more or less than I did.