In pharmacology and pharmaceutics, a<unk>  is an individual drug that represents a drug class – group of medications having similar chemical structures, mechanism of action and mode of action.<unk> s are the most important, and typically the first developed drugs within the class, and are used as a reference to which all other drugs are compared.
Prototype drug
Generic drug
Designer drug
Proprietary drug
New chemical entity
Active placebo
Drug of last resort
Biological response modifier