Adopted by the 41st World Medical Assembly
Hong Kong, September 1989
and rescinded at the WMA General Assembly,
Santiago 2005
Definition
Generic substitution is herein defined as the dispensing of a
different brand or an unbranded drug product for the drug product
prescribed; i.e., the exact same chemical entity in the same dosage
form but distributed by a different company.
Preamble
If drug products are not bioequivalent because of different manufacturing
processes and/or the presence of different biologically inactive
excipients, anticipated therapeutic equivalence among such drug
product may also change. Therefore, when substitution occurs among
drug products that are not bioequivalent and chemically and therapeutically
equivalent, the patient may be adversely affected; i.e, suffer
an adverse drug reaction or a therapeutic failure. For these reasons,
the physician should be assured by national regulatory authorities
of the bioequivalence and the chemical and therapeutic equivalence
of prescription drug products from multiple sources. This principle
is also desirable in the case of single-source drug products.
Quality assurance procedures should be in place to ensure their
lot-to-lot bioequivalence and their chemical and therapeutic equivalence.
In the drug selection process, many medical considerations should
be addressed before prescribing the drug of choice for a particular
indication in any given patient. Once these primary considerations
are met, the physician should then consider comparative costs
of similar drug products available to best serve all of the patient's
needs. The physician has both the right and the obligation to
exercise his/her best judgment on behalf of the patient; therefore,
the physician should select the type and quantity of drug product
that he or she considers to be in the best medical and financial
interest of the patient. Once the patient gives his consent on
the drug selected that drug should not be changed without the
consent of the patient and his or her physician. Even when third-party
carriers mandate generic drug substitution, every effort must
be made to preserve the prescribing authority of the physician.
Failure to follow these principles can result in harm to patients,
and physicians can be held liable for such harmful consequences.
On behalf of patients and physicians alike, national medical associations
should do everything possible to uphold these precepts.
Recommendations
- Physicians should become familiar with specific laws and/or
regulations governing generic drug substitution in locals where
they practice.
- On initiation of treatment, physicians should carefully determine
the dose of any medication for optimum efficacy and safety,
especially in patients with chronic disorders who require prolonged
therapy or patients in special population groups not expected
to respond to a drug in the normal manner.
- Once medication for chronic diseases has been prescribed
and begun, no substitution of either generic or brand-name drug
products should be made without the attending physician's permission.
If generic or brand-name substitution of a drug product occurs,
the physician should carefully monitor and adjust the dose to
ensure therapeutic equivalence of the drug products.
- The physician has the duty to report serious adverse drug
reactions or therapeutic failures that may be related to drug
substitution; the finding should be documented and reported
to appropriate drug regulatory authorities, including the appropriate
national medical association.
- National medical associations should regularly monitor generic
drug substitution issues and keep their members advised on developments
that have special relevance for patient's care. When appropriate,
information reports on significant developments should be made
available to physicians.
- National medical associations, in collaboration with other
appropriate drug regulatory bodies, should evaluate and ensure
the bioequivalence and the chemical and therapeutic equivalence
of all similar drug products, whether generic or brand-name
manufactured, in order to ensure safe and effective treatment.
- National medical associations should oppose any action to
restrict the freedom and the responsibility of the physician
to prescribe in the best medical and financial interest of the
patient.
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