I sometimes work with clients whose dogs are extremely fearful or anxious, and recommend that they discuss anxiolytic meds with their vet. Here are two articles on the topic that already say exactly what I want to convey:

Behavior Medication: First-Line Therapy or Last Resort? by Jen Summerfield, DVM, CPDT-KA

Behavioral Medication In Training by Kate LaSala, CTC, CBCC-KA, PCBC-A, CSAT, FFCP-E

Here is an article (PDF) that describes a case study, and gives information on various medications, dosages, and potential side effects to watch out for. This was written by Ilana Reisner, DVM, PhD, Diplomate ACVB and published in the journal Today’s Veterinary Practice.

You may find it beneficial to work with a veterinary behaviorist in conjunction with your primary vet. (This would be like you going to see a specialist because your GP can’t be an expert in every topic.) The UC Davis vet hospital has two certified behaviorists on staff. More information on working with them can be found here.