The
common cold is more common than you might think. The average adult will usually
have two to five bouts with the common cold a year while children may have six
to eight common cold episodes a year (Simasek, 2007). The medicine prescribed
by doctors or recommended tends to be “harmless” OTC medications; products like
Nyquil, Robotussin, with the main ingredient being dextromorphan (DXM). This
product is relatively harmless and will treat symptoms of the common cold for
most, but for those that are CYP-2D6 deficient, DXM could spell trouble, as in
psychotic trouble.
DXM, when taken in
excess, can produce euphoria, dissociation from the mind, psychosis, feelings
of omnipotence, panic attacks, hallucinations, etc. This comes from personal
experiences, albeit unintentional. I took about two times the standard dose of
Robotussin to alleviate my unrelenting coughing fit two years ago. With it, I
started to feel drunk-like and experienced a feeling of euphoria, stimulation,
social inhibition, and weird body sensations. The abnormality of this was that
it persisted for about two days. This leads me to believe I have very little
CYP-2D6.
For
some background information, CYP-2D6 is a gene that is responsible for the
breakdown of pharmaceuticals such as tricyclic antidepressants, antiarrhythmics,
and adrenoceptor antagonists (“Genetics Home Reference”, 2016). The NMDA
antagonist, DXM, is also metabolized by CYP-2D6 (Yu, 2001). A lack of this
enzyme makes the physical, as well as psychoactive effects, last for much
longer than is intended. If an adult or child takes the standard dose of DXM
three times in that day being deficient in CYP-2D6, they could experience a “high”
from DXM that could last for 24-72 hours or longer. This is because the DXM is
not able to be metabolized and taken out of the body for that period of time.
I
am not alone in this deficiently. Studies suggest that 7% of the population are
CYP-2D6 deficient. 25% of all prescription drugs are acted on by CYP-2D6.
CYP-2D6 deficiently can result in prolonged adverse effects in these
medications, most notably Prozac, Claritin, Allegra, and Vicodin, and this
deficiency can also activate the analgesic activity of certain opioids like codeine (Genelex, 2014). Based on this research, it is important to be tested for
CYP-2D6 deficiency if one experiences effects from these drugs that last longer
than it is intended.
http://genelex.com/pharmacogenetic-tests/cyp2d6/
https://ghr.nlm.nih.gov/gene/CYP2D6
https://www.ncbi.nlm.nih.gov/pubmed/?term=Characterization+of+Dextromethorphan+O-+andN-Demethylation+Catalyzed+by+Highly+Purified+Recombinant+Human+CYP2D6
References
ReplyDeleteGenelex. (2014). CYP2D6 Genotyping. Retrieved from http://genelex.com/pharmacogenetic-tests/cyp2d6/
Genetics Home Reference. (2016). CYP2D6 gene. Retrieved from https://ghr.nlm.nih.gov/gene/CYP2D6
Simasek, M., Blandino, D.A. (2007). "Treatment of the common cold". American Family Physician. 75 (4): 515–20. Retrieved from http://www.aafp.org/afp/2007/0215/p515.html
Yu, A., Haining, R. L., Lang, D., & Dong, H. (2001). Characterization of Dextromethorphan O- andN-Demethylation Catalyzed by Highly Purified Recombinant Human CYP2D6. Drug Metab Dispos, 29(11), 1362-5. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/?term=Characterization+of+Dextromethorphan+O-+andN-Demethylation+Catalyzed+by+Highly+Purified+Recombinant+Human+CYP2D6