system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do pharmacies have almost all medication in stock in such a small area?
gpt
Despite what you might think there aren't as many common medications available. Also, pharmacies only need to keep enough of any given medication in stock as long as they get frequent shipments every few days. They determine which medications are the most highly used by local physicians and stock those up enough to last until their next delivery with a safety supply always in reserve. And if they get dangerously low all they need to do is make a special order that comes a few days early. But pharmacies are getting shipments of medications all the time so this really shouldn't be a problem. Another thing that helps is that shelf life of most medications are at least a year. So even if you have to stock some exotic medication that no one really ever gets prescribed you can keep a small supply tucked away somewhere and have a computer system track when it is going to expire and you need to toss the old stuff out.