Drug Safety The term "Drug Safety" refers to the frequency of adverse drug effects that are treatment emergent, meaning that they either appear during treatment and were not present prior to treatment or that they worsen relative to the pretreatment state. These adverse effects can be physical or laboratory toxicity that may be related to the drug. Drug safety is the frequency of adverse medication effects that occur during treatment and were not evident before to therapy, or that worsen during treatment as opposed to the pretreatment condition (i.e., physical or laboratory toxicity that may be connected to the drug). The possibility of negative consequences associated with medicine administration is referred to as drug safety. The process of determining a medication's safety profile starts early on with in vitro and in vivo toxicity research, continues through clinical trials leading up to drug approval, and continues after approval with targeted post-marketing studies or more broad pharmacovigilance initiatives.