Certain complementary medicines may cause side effects, warns NPS MedicineWise

With new information from Melbourne’s Peter MacCallum Cancer Centre revealing that some complementary medicines can interact with cancer treatment, NPS MedicineWise reminds all Australians that complementary medicines can cause side effects, and interact with other over-the-counter and prescription medicines.

NPS Medicines Line Manager and pharmacist, Sarah Spagnardi, says that people may not think about complementary medicines in the same way as other medicines. Complementary medicines can have benefits, but they can also cause side effects, adverse reactions and interactions with other medicines, so they still need to be used with care.

“As with all medicines, tell your health professional about any multivitamin, herbal or mineral supplements you are taking to help avoid potentially harmful interactions. People may not always think to tell their health professional they are taking complementary medicines and this can become a problem if medicines have the potential to interact,” says Ms Spagnardi.

Complementary medicines do not go through testing processes in the same way that prescription and pharmacy medicines do before they can be sold in Australia, so often less is known about their effectiveness, possible side effects and interactions. Ms Spagnardi says the NPS Medicines Line fields numerous calls from Australians with questions about complementary medicines and interactions with complementary medicines.

“Over 50% of all calls to Medicines Line about complementary medicines are questions about drug interactions,” says Ms Spagnardi. “The complementary medicines that generate the most enquiries are Vitamin D and calcium preparations, multivitamin products, fish oil preparations, glucosamine products and St John’s wort.”

It is important to understand that certain complementary medicines may interact with prescription medicines. For example, St John’s wort is often used to alleviate depression, but can interact with several commonly used prescription medicines by making them less effective or by increasing their side effects. These prescription medicines include antidepressants, the oral contraceptive pill, digoxin, blood-thinning medicines, some cholesterol-lowering medicines, epilepsy medicines, HIV medicines, pain medicines, chemotherapy medicines and medicines used to prevent rejection after an organ transplant.

“Your doctor and pharmacist need to know about all your medicines so they can consider any possible interactions when recommending other medicines for you,” says Ms Spagnardi.

“It’s also really important to include your complementary medicines on your Medicines List so you have a record at hand. NPS MedicineWise has developed a handy smartphone app—MedicineList+—that you can use to record all the medicines you or people you care for are taking, and easily share this with your health care team,” says Ms Spagnardi.