This information comes as no surprise as health supplements are commonly found and widely consumed in Singapore, with the Health Supplements Industry Association of Singapore estimating that Singaporeans fork out nearly S$6 million on supplements in 2015 – a sum that is predicted to increase by up to 10% every year.
Medication-supplement interactions can be detrimental
According to Serena Koh, a pharmacist at the Singapore General Hospital (SGH), there is no formal data available on the number of patients with chronic illnesses who are consuming supplements. However, she revealed that it is common for pharmacists to meet walk-in patients and family members who inquire about dietary or health supplements as a complement to their prescribed medications.
Even though must supplements are labelled as “natural” and are based on plant or based sources, the active ingredients in the products can be potent chemicals.
However, as most consumers perceive health supplements as safe products, many patients do not readily disclose their use of over-the-counter supplements to healthcare providers. Unfortunately, such gaps in communication may inadvertently jeopardise patient safety as certain combinations of drugs and supplements may result in harmful side effects.
One example of a drug that may interact with supplements is the blood thinner warfarin.
“Warfarin is one of the most notorious medications known to interact with various supplements. It can interact with supplements such as omega-3 fish oils, ginkgo biloba, Vitamin K and St John’s Wort, leading to a potential risk of bleeding or clotting,” Koh explained, adding that individuals on multiple prescription drugs are at higher risk of medication-supplement interactions.
The popular supplement St. John’s Wort can also cause dangerous side effects when used with selective serotonin reuptake inhibitor (SSRI) antidepressants. Additionally, some seemingly harmless supplements may be not be suitable for patients, such as potassium supplements, which should be used with caution in patients with chronic kidney disease.
Supplements may benefit patients with chronic diseases
On the other hand, there is growing evidence to suggest that certain supplements may benefit patients with chronic diseases, and complementary medicine can be used safely with conventional drugs when taken properly, according to Dr Lesley Braun, a complementary medicine expert and director of Blackmores Institute in Australia.
“For example, research has shown that people on long-term medication for Type 2 diabetes like metformin are at risk of B12 deficiency,” she said. “Blood pressure medication, when taken long-term, can induce zinc deficiency.”
“It would make sense for pharmacists to ask patients on these medications for signs of these nutritional deficiencies and check whether they are taking enough in their diets. If they aren’t, perhaps they should look into a supplement,” she also said.
Lynette Goh, a senior dietician at National Healthcare Group Polyclinics, agreed that the elderly can fulfil their dietary requirements with the right supplements, but advised patients to consult a healthcare professional before taking such supplements even though they can be easily purchased over-the-counter.
“The doctor should also know what you are currently taking so that he or she can monitor for any side effects or any interactions between conventional medicine and supplements or herbal medicines,” Goh said. “Patients need to be aware that there are many pathways through which these interactions can take place. MIMS
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