Therapeutic Substitution is one form of drug substitution. Therapeutic substitution occurs when a pharmacist substitutes a chemically different drug for the drug that the physician actually prescribed. The drug substituted by the pharmacist belongs to the same pharmacologic class and or to the same therapeutic class. However since the two drugs have different chemical structures, potentially adverse outcomes for the patient can occur.
Genetic substitution is entirely different from therapeutic substitution.
In generic substitution, a generic drug is substituted for a brand name drug. However, both drugs have the same active chemical ingredient, same dosage strength, and same dosage form. The prescription of a drug represents the culmination of a careful deliberative process between physician and patient aimed at the prevention, amelioration or cure of a disease or problem. This deliberative process requires that the physician evaluate a variety of scientific and psychological data including costs and make an individualized choice of therapy for the patient. Physicians have the responsibility for diagnosing the patient's condition and for the development of a treatment plan, including the prescribing of appropriate drugs and medications.