Home' Australian Pharmacist : Australian Pharmacist April 2015 Contents Australian Pharmacist April 2015 I ©Pharmaceutical Society of Australia Ltd.
CONTINUING PROFESSIONAL DEVELOPMENT
with the impact of pharmacogenomics
on all medicines, not just conventional
medicines. Pharmacogenomic influences
should be particularly considered if
patients are showing unexpected signs
or symptoms after taking conventional
or herbal medicines. Pharmacists need to
be aware that, analogous to conventional
medicines, genotype differences can
cause patients to have different responses
to complementary medicine that may
impact upon drug efficacy and patient
safety and that many herbal medicines
have not been subjected to adequate
scientific research in this regard.
• PharmGKB. At: www.pharmgkb.org
• Table of pharmacogenomic
biomarkers in drug labelling. At: www.
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mechanistic and clinical considerations. Curr Drug Metab
11. Durr D, Stieger B, Kullak-Ublick G, et al. St John’s wort
induces intestinal p-glycoprotein/MDR1 and intestinal and
hepatic CYP3A4. Clin Pharmacol Ther 2000;68(6):598–604.
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CYP3A4 activity. Clin Pharmacol Ther 2000;67(5):451–7.
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wort on CYP2C19 activity with respect to genotype. J Clin
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St John’s wort in healthy subjects. Clin Pharmacol Ther
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phenotypic ratios for predicting herb-drug interactions in
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interaction of digoxin with an herbal extract from St
John’s wort (Hypericum perforatum). Clin Pharmacol Ther
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herb-drug interactions: experience with Ginkgo biloba
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As is apparent from the examples
above, many of the pharmacogenomic
phenomena that have been discovered
so far involve P‐gp or various CYP
enzymes. These have been among
the best‐studied molecules in this
context, but there are many more
metabolising enzymes and transporters
of pharmacogenomic importance still
to be characterised. Further research is
needed to determine the importance
of pharmacogenomic variation in
determining the clinical outcomes of
potential herb‐drug interactions.
The complexity of herbal medicines
also creates challenges in this new
field. The lack of standardisation of
many herbal medicines can limit
interpretation and extrapolation of the
results of genetic studies.
the levels of at least one of the possible
active constituents in St John’s wort,
hyperforin, varies between different
The impact of
genetic variance on complex herbal
medicines comprised of multiple
potentially active or synergistic
constituents, or on herbal formulas
comprised of many different herbs,
also needs further research.
In conclusion, since many Australians
now regularly use herbs and other
complementary medicines, it is important
from the clinical practice perspective for
pharmacists to become more familiar
1. Pharmacogenomics has the potential
to improve our understanding of a
c) Herb-drug interactions.
d) All of the above.
2. Which of the following is an
important drug transporter that is
affected by genetic polymorphisms?
b) P-glycoprotein (P-gp).
c) Omeprazole hydroxylase.
d) All the above.
3. Based on existing research, which
of the following are affected by St
b) P-glycoprotein (P-gp).
d) All of the above.
4. Which of the following herb-drug
pairs has been reported to interact
in a manner that is influenced by
a) Garlic and saquinavir.
b) Ginkgo and omeprazole.
c) Ginger and warfarin.
d) St John’s wort and cyclosporin.
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