Using DNA to minimise risk

Most of the laboratories only test for a few genetic markers‚ as also indicated in this test‚ which are not enough for personalised treatment. The idea of ‘one size fits all’ has changed over the time and a ‘personalised’ medicine approach has emerged. PHOTO | FILE

What you need to know:

  • While experts warn that genetic testing to determine how a person will respond to medication is not yet advanced enough to help the average patient, they say that the new test‚ which uses a swab from the cheeks‚ can detect personal response of upto 150 medications used for pain‚ heart disease‚ high cholesterol, and depression.
  • Dr Chaudhry explained there are genetic variabilities that affected how people reacted to some drugs such as warfarin — which is used to stop blood-clotting — and the common pain killer codeine‚ where some people get “high”.
  • With an objective to maintain safe and rational use of medicines, adverse drug reaction monitoring centres are being set up to collect and evaluate spontaneous reports of adverse reactions to medicine

A new genetic test could predict if you will react badly to certain medicines or not respond to certain drugs at all.

The test, called mygeneRx‚ analyses the patient’s DNA and looks at the genetic variation in genes that control drug-using enzymes. It was created by a South African company, DNAlysis.

These enzymes allow a drug to be used (metabolised) by the body so fast that it gets rid of the medicine before it has time to work‚ or very slowly so the body can have difficulty eliminating the drug. The slow metabolism rate, however, could lead to an overdose and unintended side effects.

While experts warn that genetic testing to determine how a person will respond to medication is not yet advanced enough to help the average patient, they say that the new test‚ which uses a swab from the cheeks‚ can detect personal response of upto 150 medications used for pain‚ heart disease‚ high cholesterol, and depression.

Dr Mamoonah Chaudhry‚ a postdoctoral fellow at the University of Pretoria’s Institute for Cellular and Molecular Medicine, explained that the field of individual testing, known as pharmacogenomics, can help warn of a person’s likelihood to have bad reactions to a drug.

“The personalised medicine approach will help reduce mortality and morbidity due to adverse (bad) drug reactions,” said Dr Chaudhry.

She‚ however‚ warned that current genetic tests were not advanced enough to be used widely to guide doctors on what medication to prescribe.

SAFE AND RATIONAL USE

“Most of the (laboratories) only test for a few genetic markers‚ as also indicated in this test‚ which are not enough for personalised treatment. The idea of ‘one size fits all’ has changed over the time and a ‘personalised’ medicine approach has emerged.”

Dr Chaudhry explained there are genetic variabilities that affected how people reacted to some drugs such as warfarin — which is used to stop blood-clotting — and the common pain killer codeine‚ where some people get “high”.

With growing concerns about adverse drug reactions, governments are introducing measures to protect patients from the side-effects of drugs.

Incidence and severity of adverse drug reactions vary by patient characteristics (age, sex, ethnicity, coexisting disorders, genetic or geographic factors) and by drug factors (type of drug, administration route, treatment duration, dosage).

With an objective to maintain safe and rational use of medicines, adverse drug reaction monitoring centres are being set up to collect and evaluate spontaneous reports of adverse reactions to medicines, vaccines, medical devises and herbal products from all health care professionals and customers.

The Pharmacy and Poisons Board (PPB) has come up with a form where the public can report suspected cases of adverse drug reactions. The yellow form can be downloaded, filled and e-mailed back to the board.

“When a drug reaction is suspected, the doctor will investigate whether the particular drug is known to cause such a reaction, rule out other alternative explanations, and establish the link between the time the reaction occurred and when the medicines was administered,” explained Dr Christabel Khaemba, who heads the pharmacovigilance department of the board.