Discovering the interaction between medical drugs and local herbs

Associate Professor Dr Ong Chin Eng - School of Pharmacy
Associate Professor Dr Ong Chin Eng - School of Pharmacy

Unbeknownst to many patients and even medical practitioners, the incidence of negative side effects due to the interaction of prescribed drugs with certain foods, herbs and other drugs, is a serious and increasingly common problem around the world. In the United States, recent studies have shown that up to 50 percent of adverse drug effect cases have been due to drug-drug, drug-herb, drug-food interactions, underscoring the severity of the problem.

“In Malaysian hospitals, the problem of patients developing side effects from consuming prescribed drugs which interact with the food or herbs they consume is actually a very common problem. However, because sometimes even patients themselves are not aware of this, they don’t report it,” said Associate Professor Dr Ong Chin Eng from the School of Pharmacy at Monash University Malaysia.

Since 1998, Dr Ong, who is actively involved in pharmacology research, embarked on a research into the enzyme cytochrome P450, which is responsible for metabolising up to 80 percent of commonly-prescribed drugs in the human body.

Dr Ong specifically set out to determine if the enzyme’s activity was affected which may lead to altered drug response when mixed with local herbs, specifically Tongkat Ali, Kacip Fatima, Misai Kucing, Hempedu Bumi and Pegaga. “I decided to study the interaction of these herbs with certain drugs, as these herbs are readily available here and widely consumed, especially among the ethnic Malay community,” he said, adding that much research has already been done on Western herbs.

Dr Ong’s research concluded that Kacip Fatima showed good potential to interact with a cytochrome P450 iso form which mainly metabolises painkillers as well as anti-convulsants and anti-epileptic drugs. The herb was also shown to interfere with warfarin, a commonly-prescribed blood-thinning agent.

His findings also showed that Misai Kucing has good potential to interact with anti-psychotic and anti-depressant drugs. “The other herbs didn’t show much potential for interaction, so patients taking these herbs have a lower chance of developing adverse response to the drugs they are prescribed,” he said.

His findings are the first of its kind to find a link between these common local herbs, and commonly prescribed drugs, alerting medical practitioners of a reaction many have never even been aware of before.

Dr Ong said he believes his research can serve as a guide for doctors, alerting them on possible interactions. Medical practitioners can also watch out for ‘warning’ signs of interaction, and advise patients according during the course of treatment, he said.

Dr Ong’s research has been documented in numerous international papers which are published in well-established journals focusing on herbs, and in some pharmacology journals focusing on drug interaction.

He currently collaborates closely with other local and international universities, as well as the Institute of Medical Research, one of the country’s premier institutions of research.

“I believe that the findings of my research can be a guide for further research which will ultimately lead to lower incidence of such problems in drug treatment. Ultimately, our goal is to improve the quality of healthcare in this country,” he said.

At Monash University Malaysia, Dr. Ong teaches pharmacology and pharmacy practices, where clinical-related topics such as drug-drug interactions are explained. Dr Ong is actively involved in pharmacology research with particular interest in drug metabolism and pharmacogenetics of drug-metabolising enzymes.

“Very often, I directly apply what I research and work on, into my lessons and share them with my students. It benefits the students as they know what the latest research findings are,” he concluded.

For more information on programs from School of Pharmacy at Monash University Malaysia, please visit