Is "dude" actually suffering from anxiety, or is it just a con to get a script? In my friend Nanook's experience, he always went to a behavioral health clinic for psych meds, rather than to a actual psychiatrist's office and, while it was considerably cheaper, they wanted you to jump through hoops to get the meds. Multiple counseling sessions and things like that. It was a pain in the ass, but they did give them to Nanook eventually.
Does dude have a family doctor or General Practitioner with a local clinic? In some areas, they will prescribe for dudes condition. Not in Nanook's old home town, but they do in his new location.
As far as requesting a specific drug
, dude have several options. He could just come right out and ask for what he wants. Tell the doctor that he researched the drug and that's what he wants to try first. Dude could research the indicated uses for the particular drug and use those as descriptive terms when stating his symptoms to the doctor. That might be considered somewhat shady, but people do it all of the time. He could tell the doctor that he had had adverse reactions in the past to whatever the doctor wants to prescribe and then use a combination of the first two suggestions.
He could just try being honest with the doctor and let him make the decision as to what is best for dudes condition! If he has actual anxiety issues, that is.