FRIDAY, Nov. 19 (HealthDay News) -- A new, small study suggests
that the main ingredient in cough syrup might help doctors
determine the best dose of tamoxifen, a drug commonly used to
prevent and treat breast cancer.
The idea is that the body absorbs cough medicine at about the
same rate as tamoxifen, allowing doctors to use it to test how
patients respond to the breast-cancer drug.
"This study is starting to identify a personalized medicine type of approach that will help identify those patients who should have their tamoxifen doses adjusted," said Dr. Leonidas Koniaris, who's familiar with the study findings. He's an associate professor of surgery at the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine in Florida.
Currently, it can be difficult to set a proper dose of tamoxifen
for a patient. If the dose is off, the drug may lose effectiveness
or cause a higher number of side effects, the study authors
The authors, led by Anne-Joy de Graan, a graduate student at
Erasmus Medical Center in Rotterdam, the Netherlands, focused on
whether dextromethorphan, the active ingredient in cough medicine,
is metabolized by the body at about the same rate as tamoxifen.
Dextromethorphan "is a so-called 'probe' drug, a harmless substance
that can be used to predict the metabolism of another drug," de
Graan said in a news release provided by the European Cancer
The study authors gave 30 milligrams of dextromethorphan in
cough syrup form to 40 breast cancer patients and then gave them
tamoxifen two hours later. Over the next 24 hours the researchers
determined whether the women's bodies metabolized the drugs at
similar rates. They did.
The cough medicine test needs more research and isn't ready to
be used in doctors' offices, Koniaris stressed. The next steps will
be to validate the research and see if the test results actually
lead to better health for patients. For now, he said, "it certainly
looks quite promising."
The study findings were to be released Friday at the Symposium
on Molecular Targets and Cancer Therapeutics in Berlin, Germany.
Research presented at meetings should be viewed as preliminary
until it is published in a peer-reviewed journal.
There's more on tamoxifen at the
U.S. National Cancer Institute.