Q: A couple of years ago, I saw my nurse practitioner for a urinary tract infection (UTI). They prescribed me a 500 mg pill for seven days, and by the end of treatment, all my symptoms were gone - I felt great. About a week ago, I started feeling the familiar signs of another UTI and went to see my pharmacist. After reviewing my symptoms and medical history, they determined it was an uncomplicated UTI and prescribed a 100 mg pill for five days. To my surprise, it worked just as well as the higher dose I took a few years ago! How it is possible that a dose five times smaller and taken for a shorter time, could be just as effective?
I have asked my colleague, Dr. Bradley Adams, a pharmacist at the Dr. Georges-L.-Dumont University Hospital Centre in Moncton, to take a closer look at how medication works:
Thank you so much for writing in! I am so happy to hear that you are feeling better. This is a very common question we get as pharmacists and I’m glad to take some time to chat about the science behind medications in this week’s Ask Your Pharmacist column.
Generally speaking, medications work by both finding and connecting with very tiny molecules called receptors. These receptors then trigger what is known as a response - this is how the medication does what it needs to do. The process of finding and attaching to these receptors, called pharmacokinetics (which is the study of how a drug moves through the body), is a very important part of a pharmacist’s university education here in Canada. Understanding how medications work is just as important as understanding why we take them.
When medications are developed in labs, prescribed in various health-care settings, and finally given to you by your pharmacy team, the same goal is always top of mind: to make sure you have the safest treatment with the least side effects while making sure that we are treating what needs to be treated in the best way possible.
Medications are constantly improving as science advances. Just tiny changes to a drug can help it target certain areas of the body more than others, stay in the bloodstream longer than others, avoid certain areas of the body to reduce side effects, allow it to be taken by mouth instead of by injection, require it to be taken less often, and so much more. Sometimes, we even need to combine the effects of two or more medications so their actions can complement each other and achieve the desired effect.
When it comes to antibiotics, there are a number of things to consider because different regions (yes, even within our tiny province) have different levels of what’s known as antibiotic resistance. Different antibiotics will work better depending on where you might be located because bacteria are learning how to avoid being killed by antibiotics. Whether it’s antibiotics, blood pressure pills, chemotherapy, or pain medications, different doses, number of days of treatment, and times per day are often needed to make sure that what is being treated is done so in the best way possible. If you ever have questions, don’t hesitate to reach out to your pharmacist – we’re always happy to help!
As the proud son of a New Brunswick potato farmer, I always like to use potatoes as an example when explaining this concept to my patients. If you don’t cook a potato, it is not only heavier (higher milligram amount), but your body does not digest it very well. If you take a bit of time to boil that potato in water, it is lighter (lower milligram amount), and your body will likely digest it much easier. At the end of the day, it is still the same potato - but small changes can make a big difference.
Dr. Bradley Adams (BScPharm, PharmD) is a graduate of the Dalhousie University College of Pharmacy and the Memorial University of Newfoundland School of Pharmacy. He is primarily a hospital pharmacist practicing at the Dr. Georges-L.-Dumont University Hospital Centre in Moncton, NB. The views expressed in this article represent his own and do not necessarily reflect those of Vitalité Health Network. His opinions expressed in this column are published for educational and informational purposes only, and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis, treatment or as a substitute for professional medical advice, diagnosis or treatment. Send your questions to AskYourNBPharmacist@gmail.com.