Brand-Name vs Generic Agents: The Prescriber Experience
Prescribers and patients often voice concerns about the safety and efficacy of generic drugs that are substituted for brand-name drug products. Love 'em or hate 'em, they are with us to stay. The US Food and Drug Administration (FDA) approves a generic substitute if it has proven to be "identical, or bioequivalent, to a brand-name drug in dosage form, safety, strength, route of administration, quality, performance characteristics, and intended use."[1]
The FDA's Orange Book provides the latest information on generic approvals. Approved generic agents have been demonstrated to have therapeutic equivalence -- although many providers have questioned whether that equivalence extends to all patients and all clinical scenarios. Jenny Van Amburgh, PharmD, an associate clinical professor of pharmacy at Northeastern University in Boston, Massachusetts, reminded prescribers in a previous discussion on Medscape that generic products are only compared with their brand-name products and not with generics made by other manufacturers.
Drugs that are known to exhibit a narrow therapeutic index (NTI), including levothyroxine, warfarin, phenytoin, and digoxin, are of greatest concern. Switching between generic NTI products made by different manufacturers may require particular vigilance to recommended monitoring.
James Lindon, PharmD, PhD, JD, in an earlier article on Medscape, noted that the product liability law applied to prescription drug products usually only requires the manufacturer to disclose "adequate warning and instruction" to the prescriber or dispenser. There may be no duty for the drug product manufacturer to warn the patient.[2] In contrast, the prescriber and pharmacist may have a duty to counsel the patient when a particular generic product is prescribed or selected by the pharmacy. Laws regarding substitution vary by state.
What if the generic substitution is required by a patient's insurance carrier? Or the switch to a generic drug from a different manufacturer is made at the pharmacy and the prescriber is not aware of it? Is the prescriber liable? Prescribers may not know which generic product was dispensed at the pharmacy or why that agent was chosen. They may not be aware of any concerns about the product selected.
We asked our prescribing readers to participate in a survey describing their experience with generic agents and their opinions on the appropriateness of their use. Here is what they had to say. Who Participated?
Over 1400 physicians (64% of the sample), nurse practitioners (32%), and physician assistants (4%) completed the survey. Respondents were fairly equally divided in their practice settings. Approximately 27% indicated that they practiced in a private primary care practice, 27% in a private specialty practice, and 27% in a nonprivate clinic (hospital, federally qualified health center, or public health); the remaining 19% were hospital-based (emergency medicine or hospitalist). The respondents were an experienced bunch: More than one half -- 56% -- had been in practice for over 16 years. An additional 16% reported 6-15 years' experience. Only 8% reported practicing for 2 years or less.
How Frequent Are Generic Substitutions?
We asked whether respondents had been required to make a generic substitution by an insurance carrier in the previous 6 months. Over 70% of respondents indicated that they had indeed been required to make a substitution, compared with 22% who had not. Often that substitution was made without notification of the prescriber. Almost two thirds (62%) of participants indicated that they had not been notified, one quarter (25%) had been notified, and the remainder could not recall.
An overwhelming majority of respondents indicated agreement (26%) or strong agreement (52%) with the statement that a dispensing pharmacy should be required to notify prescribers when making a switch from a brand-name to a generic agent or between generic products made by different manufacturers. Approximately 7% disagreed, and 12% indicated that they did not have an opinion. Dr. Lindon notes that there are pragmatic concerns in implementing prescriber notification about medication substitutions, particularly when changing between generic manufacturers. Multiple pharmacist calls to clinician practices could be cumbersome for both the pharmacy and the prescriber and be potentially disruptive and intrusive. He questions how often a prescriber would find such information useful, object to a change in manufacturer, or request more information about the manufacturer or generic product.
One pediatrician grumbled that insurance companies were "calling the shots" and not notifying providers or patients. However, a pharmacist reader wrote that a change from a brand-name drug to a generic was as often made because of patient requests as because of insurance requirements, with patients citing higher out-of-pocket costs for brand-name medications. A family medicine physician agreed, noting that many patients would not be able to afford medications without lower-cost generic alternatives. Other barriers to the use of brand-name agents cited by our survey participants included requirements for prior authorization, prohibitive paperwork, and potential delays to start of therapy.