Final answer:
Thiamine should be administered first to prevent Wernicke-Korsakoff syndrome in an unconscious adult female with low blood glucose.
Step-by-step explanation:
The first medication that should be administered to the unconscious adult female to prevent Wernicke-Korsakoff syndrome, after initiating oxygen therapy and IV access, is thiamine. Thiamine, also known as vitamin B1, is essential for brain function and glucose metabolism. Alcoholics are at risk of thiamine deficiency, which can lead to neurological complications such as Wernicke-Korsakoff syndrome.