How can I reach her?

try to established a rapport for her!! invite her to watch movie with you and try to put yourself in her shoe..well its never too late shes your sister anyway!goodluck

It is pretty tough, teens now days, or in general always see anyone who is NOT a teen as someone they don't want to get close to. I'm the youngest of my family and my sister is 5 years older then me. I have another sister who is 7 years older then me and I didn't start really bonding with them until I was older. I think the problem with your sister might be the medication. It doesn't help with the situation. But if you want to become close with her I think physical time with her. If you're far away then it will be even harder to get along with her. Honestly the bonds should be formed while growing up, but just trying to hang out with her should be a good start. Take her shopping and other things, things she likes to do and things you like to do. Then strike up conversations and tell her stories about yourself and share things you've never told your parents. Remember, she might not open up to you all the way, but a little is all you need. She'll need to get hurt and learn on her own time, the best you can do as a sister is cushion her fall and make sure it doesn't go too far. Especially with the guys. Teens don't want to hear who they shouldn't go out with, it'll make them even worse. Just be forward with your own concerns and say they you'll let her make the decision and open yourself up to conversation when she needs it. Tell her day or night if she needs you she can come to you, you'll need to make yourself available too. Hopefully this helps, but I don't know your sisters personality either. But try different things and see what she responds to the best.