You should be able to get all the meds you mentioned with the possible exception of Ritalin, not so sure about it, but check out the http://www.minsa.gob.pe/
. That's the ministry of health website.
I traveled a lot for work before moving to Peru and never had an issue with getting prescriptions filled in as little as 48 hours, since I already had existing prescriptions with my doctor. You should make a call to your DR, I think you would be a lot better off than just coming here without all those meds.
Other posters have asked about adderal and other amphetamine based Rx`s for ADD and received mixed reviews. Most have said that without a local MD Rx that you can`t receive them... others have said they have had some success. My overall impression is that amphetamine type Rx`s are relatively controlled and therefore tough to get without an Rx... similar to narcotics... even moderate narcotics like Trazadone... not to mention stronger scripts like Xanax or hydrocodone....
I think you are confusing benzodiazepine(xanax), anti-depressant(trazadone) and narcotic like Vicodin(hydrocodone). Benzodiazepines are easy to get. Xanax is available as the generic Alprazolam. You do need a prescription to get it.