I don't know about Venezuela or this island in pariticular, but if it's anything like Costa Rica or Brazil (not too far away) you will be able to get benzos and some codeine products from the pharmacist by describing your problems, or by saying you left your prescription meds at home. You won't be likely to find any pain meds stronger than codeine.

For some meds (ritalin for instance, or other stimulants) the pharmacist might send you to a local clinic for an actual prescription. Aside from codeine and benzos, though, you might have trouble finding the meds you are used to getting from Spanish, Mexican and Argentine IOP's. A lot of those meds seem to be diverted for export.

But then I'm no expert!

Have a great pain free trip!