Or, here's a thought, they could have actual medical issues that require the medication and makes leaving the house difficult. Which, gee, anti-convulsants are used to treat bipolar disorder, migraines, and... seizures. Which it's dangerous to leave the house by yourself if you have seizures because, gee, it'd be awful dangerous to be crossing the street and start having one. IF there were even any stores within walking distance that would still be open by the time OP got there. Also, there are in fact completely alcohol free beers. And, to be blunt, your assumption that OP is a drug addict because they didn't go get bottled water when there were context clues as to why that wasn't an option, is really rude and unnecessary.

as GhostFox stated...the OP is on the meds FOR A REASON! How do I know? He takes ANTI-CONSULTANTS which means he is MOST LIKELY EPILEPTIC. and YES there are some A-Cs that cause insomnia and severe depression. How do I know that? because I am Epileptic and take the EXACT SAME MEDS, outside the sleep aids as I take those ONLY AS NEEDED.