A medication dispensed based on a physician's prescription; prescription drug (as opposed to over-the-counter drugs).
風邪で病院を受診したら処方薬を出され、薬局で受け取った。
When I went to the doctor for a cold, I was given a prescription drug and picked it up at the pharmacy.
処方薬は用法・用量を守らないと副作用のリスクが高まる。
If you don't follow the prescribed usage and dosage of prescription drugs, the risk of side effects increases.
子どもに薬を与えるときは、処方薬か市販薬かを確認してから投与する。
When giving medicine to a child, check whether it's a prescription drug or an over-the-counter drug before administering.