Premedication
Premedication refer to a drug treatment given to a patient before a (surgical or invasive) medical procedure. These drugs are typically sedative or analgesic.
Premedication before chemotherapy for cancer often refers to special drug regimens (usually 2 or more drugs, e.g. dexamethasone, diphenhydramine and omeprazole) given to a patient minutes to hours before the chemotherapy to avert side effects or hypersensitivity reactions (i.e. allergic reactions).