noun
adhesive skin patch; transdermal patch; medical patch
Refers to a medicated patch that adheres to the skin to deliver medication through the skin.
腰痛に貼り薬を使っています。
I'm using a medical patch for my back pain.
この貼り薬は一日一回交換してください。
Please change this patch once a day.
Compound of 貼り (hari, 'sticking') + 薬 (kusuri, 'medicine'). The reading はりぐすり is a straightforward combination of the kun'yomi readings.