Physician using pharmacogenetics to determine best medications for individual patients – The Times and Democrat

A local family physician is taking much of the guesswork out of patient treatment with the help of drug-gene testing that determines how a persons genes affect their bodys response to medications.

The testing is also known as pharmacogenetics, a combination of the words pharmacology (the study of the uses and effects of medications) and genomics (the study of genes and their functions).

Dr. Monnie Singleton of Singleton Health Center in Orangeburg has been using pharmacogenetics testing for nearly a year to determine safe and effective medications and doses that will be tailored to a persons genetic makeup.

Pharmacogenetics testing is a revolutionary means of checking to see how patients are metabolizing the medications that they are taking. So were looking specifically at how a medication is metabolized by an individual, Singleton said.

He said drugs dont work the same for everyone and while it can be difficult to predict who will benefit from a medication, who will not respond at all and who will experience adverse drug reactions, the testing helps him eliminate the trial-and-error associated with prescribing medications.

This technology eliminates the need for us to just keep guessing at what might be the right medicine in an individual patient. I think as we move forward, were going to be looking specifically to see if the genetics in patients DNA makeup will allow proper metabolism of that drug, he said.

Singleton added, If the drugs arent metabolized normally, what we see in many people is that either not enough or too much enzyme is produced. If not enough enzyme is produced to metabolize the amount of medication the patient is taking, the patients blood levels of that drug will increase to the point of becoming toxic and them getting side effects and other adverse drug reactions.

If a person is manufacturing or making too much of the enzyme, then the medicine doesnt stay in their system long enough to work and it is being metabolized too rapidly.

Enzyme is a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.

A small blood or saliva sample can help determine whether a medication may be an effective treatment for patients.

Singleton said a sponge is used to swab a patients mouth. The specimen is then shipped off for testing to Lawrenceville, Georgia-based, Alpha Genomix Laboratories, a molecular diagnostics laboratory dedicated to providing personalized patient care. Lab pesonnel look for changes to one or more genes that can affect a patients response to certain medications.

Singleton said a printout of an individual patients lab results are then sent back to his office.

We are testing for 26 different enzymes, or metabolic pathways, with this technology, he said.

Itll give a printout of several different classes of drugs. Whether that patient is taking drugs in that other class or not, it will still give a report as to whether a patient would metabolize it normally or not. So if a different medication needed to be prescribed for a different condition in the future, we could look at that list and see exactly what would be the best medication to start with, Singleton said.

The physician said 60 percent of his patients are on Medicare or Medicaid, both of which pay 100 percent of the testing cost.

The private insurances are beginning to pay for it, but they are not paying for it 100 percent, Singleton said.

What I have seen and have better come to understand is that 40 percent of the time, the antidepressants that are used with that trial-and-error method are the wrong medication. Using this guided therapy, or looking at the results of pharmacogenetics testing, allows me to select an antidepressant that the patient metabolizes normally," he said.

I select that medication to begin with and as a result, people get better quicker," Singleton said. "Ive certainly seen that in the area of depression. I have also seen it in the area of arthritis, gastroesophageal reflux disease and even when prescribing the statins for elevated cholesterol."

Patients who have had adverse drug reactions in the past and those who are taking five or more medications are among those who are recommended for pharmacogenetics testing, he said, noting that family members of patients who may not have had a good response to a medication may also be provided recommendations to see if they may benefit from testing.

Singleton said the testing is worthwhile and needed because it costs the federal government in excess of $3.5 billion a year to treat adverse reactions to drugs.

Forty percent of these adverse reactions are estimated to be preventable," he said.

I would say the overwhelming majority of the patients that we have talked to about the technology have elected to have the test done," Singleton noted. "On average, were having to make some change in a medication that the patient has been taking 30 percent of the time."

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Physician using pharmacogenetics to determine best medications for individual patients - The Times and Democrat