noun, noun or participle which takes 'suru', transitive verb
single-dose medicine; medicine taken as needed
Refers to a dose of medicine prescribed to be taken only once, typically when symptoms appear, rather than on a regular schedule. Common in medical contexts.
頭痛がひどいときは、頓服を飲んでください。
When you have a bad headache, please take the single-dose medicine.
This medicine is to be taken as needed, so you don't have to take it every day.