Let’s start with international adoption. I suggest you look at the Country Charts at CreatingaFamily.com. In your case, you will have to do a bit of reading between the lines here. Usually, I tell people to start with their limiting factors, such as age or marital status, but many countries will make exceptions to their stated requirements for families looking for a child with special needs. For you, the greatest limitation will be your inability for at least one of you to travel, and your strong preference to not adopt a child who was prenatally exposed to alcohol or drugs. There are some countries, however, that may not require you to travel at all. Check the charts for more details.
Of course, you should also consider domestic adoption. Since you have already adopted from the US, you are probably familiar with the process. It's possible to adopt a child with special medical needs from a private adoption, but most of these medical needs will be more severe since minor medical needs do not usually make a baby hard to place in the US. Children with medically related special needs are also available from the US foster care system. As a general rule, you are not limited to your own state when adopting from foster care. I include various photo listings for children available from foster care at the Adoption Resources page of CreatingaFamily.com. Make sure that you let the social workers know that you are adamant about not adopting a child that may have been exposed to alcohol or drugs, since this may significantly limit the children that are available to you. Good luck with this journey.