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Compounding Pharmacists Should Offer Pharmacogenomics (PGx) Services
Physicians and pharmacists have long known that:
- not all drugs are for everyone
- patients respond to drugs differently, and
- some patients are "responders" and others are "nonresponders"
Treating nonresponders:
- puts those patients at unnecessary risk for adverse events,
- provides no benefit, and
- may delay treatment with an effective agent
FDA encourages the use of PGx and is supporting its translation into personalized medicine. The "one-size-fits-all" model of drug treatment is outdated and it is important to be able to predict-before treatment is initiated:
- who won't respond to a particular drug or
- who will suffer unacceptable adverse events, and
- to identify the correct dosage in those who will benefit from therapy
Questions to ask before prescribing a drug:
- Does this patient have normal target receptors for the drug to be administered?
- Will the patient metabolize this drug normally?
- Is the drug transported normally in this patient?
In many cases, the answers can be provided by PGx testing and will lead to personalized treatment. From the results of such tests, a compounding pharmacist can develop and record for each patient a profile of drug response indicating abnormalities in target receptors or a genotype that interferes with drug metabolism. Please note this should be done at the patients' pharmacy as patients use more than one physician but typically only one pharmacy. From that information, an accurate dose can be prepared in a form most acceptable to that patient. The compounding pharmacist plays an important role in making those customized therapies available and adjusting them as needed during the course of treatment.
Most drug manufacturers will not find it economically feasible to produce multiple strengths and dosage forms of drugs required to provide truly individualized care. PGx and compounding are the perfect combination, and PGx data will provide an even greater scientific basis for compounding in the future.
In the past, we have looked at drug dosing macroscopically, but now, with PGx tools, we can individualize drug therapy more scientifically. Compounding pharmacy has always been involved in personalizing drug care, but without the scientific predictions that PGx allows, most prescribing by physicians has been based on post-administration results or "trial and error."
Compounding is the perfect tool for bringing PGx into reality in clinical practice to benefit patients.
A compounding pharmacist can offer truly individualized medications that will produce the optimal result for each patient's genotypic profile. Free of additives, dyes, and allergenic fillers, compounded medications can be easily adjusted in dose or dosage form as the patient's therapeutic needs change. PGx will soon become a part of both the pharmaceutical industry and the pharmaceutical specialty of compounding.
As previously mentioned, since most patients use more than one physician, maintenance of the patient's PGx data in their pharmacists' database is reasonable and physicians can consult with the pharmacist and the pharmacist can check all potential problems with incoming prescriptions from multiple physicians for each patient.
To address this topic, the next several Newsletters will cover the following topics related to PGx.
- Definitions
- History
- Theory
- PGx Testing
- PGx Tests Available and Sources
- Drugs Benefiting from PGx Monitoring
- Cases
- Implementing a PGx Program in Your Pharmacy
- Concerns Related to PGx
- Economics of a PGx Program
- Future of PGx and Compounding Pharmacy
In addition, resources will be made available on our websites that can be used in supporting your PGx program.
Loyd V. Allen, Jr., PhD, RPh
Editor-in-Chief
International Journal of Pharmaceutical Compounding
Remington: The Science and Practice of Pharmacy Twenty-second edition
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