How do you deal with a son that has an addiction?

[LONESOME]

Sorry to overwhelm everyone with my problem it seems like we are letting it all out today, my son is 17 years old he will be 18 in December and he has been in one after another type of trouble and now for the past year he has been using pot it used to be on the weekend now is everyday he was taking lortabs from me he said he was not taking them but I don't know we do drug test and all that shows is marijuana always my husband has kick him out several times and we always take him back after a week. Well 10 days ago I found out he is also doing "xanix bars" yeah what I know of xanix bars is that is xanax thru the nose but not sure and that he tries anything he can get his hands on, the same day I found out we did a drug test the ones you buy at the walgreens and again the only thing was marijuana but of course the test was limited to 4 things meth,coce,marij,opiates.
My husband and I talked to him and my husband told him that it was enough and that he had to respect the house and us ant that the next time that we see him using or druged out we will kick him out of the house, he has put us through soooo much and we are fed up with him we have 2 young girls in the house that know so much already things that they shouldn't know because of my son.
Anyways 2 days later my husband is driving my daughter to soccer practice and sees my son coming out of walgreens all druged out his eyes red he could hardly talk to him, so my husband kick him out of the house AGAIN but this time is diffrent he has not made contact till today is been about 8 days and he send a text telling me to text back so I did and he didn't txt back his girl friend txt me and said we need to take him back bc he will be in a park bench sleeping soon bc his friends parents are bigining to ask "why is he not going home".
I really don't know what to do and how to deal with this so far I have left my husband to deal with the hole situation bc what I'm going thru my self but this is killing me I love my son so much and I don't know if we are doing the right time by kicking him out, I'm sure you have gone thru this or know someone or just can say something to help me please any advise I will thank you so much
GS

[LONESOME]

Thank you yeah I been calling around to see what I can do so far nothing but I will keep trying.
Thanks

[Crispy]

If hes still 17 you can maybe have him comitted and get him some theraputic help. If hes a danger to hiself you can baker act him idk if thats a option in your state but it is in FL. He's a young man and his minds still developing so either commit him, put him in a inpatient rehab, or put him in jail if all else false i promise you he will thank you later my mom threw me in jail when i lived with her for stealing and forging checks of hers and our relationship has been closer ever since. Im just spit balling these may not be options for you but i was just giving you my 2 cents.