Medicine used to relieve headaches, such as over-the-counter analgesics or prescription drugs.
ひどい頭痛がしたので、近くの薬局で頭痛薬を買った。
I had a bad headache, so I bought headache medicine at the nearby pharmacy.
慢性的な頭痛には、鎮痛薬（頭痛薬）だけでなく原因の検査が必要だ。
Chronic headaches require investigation of the cause, not just painkillers (headache medicine).
医師に相談せずに長期間頭痛薬を常用するのは避けたほうがいい。
You should avoid long-term regular use of headache medicine without consulting a doctor.