both of which are rather fast-acting and very effective for many cases of acute anxiety and other stress responses. Most mental health professionals and primary care physicians should be familiar with these uses. They may recommend trying out the medication before your trip so that you're familiar with its effects.
The benzodiazepines (such as Valium, which someone else in this thread suggested) can be addictive with frequent use, so it may be preferable to get small-quantity prescriptions occasionally rather than stocking up.
