Q: I often forget to take my multivitamin because I need to take it separately from the Synthroid I take for my thyroid. How come I can’t take them together? What would happen if I did?
Our thyroid is a gland located in the middle of the lower part of our neck and it is responsible for producing hormones that help to regulate our metabolism. Metabolism is the chemical reactions that occur in our body to produce the energy our body needs to function properly.
Hypothyroidism is a medical condition that is often described as having an underactive thyroid and it happens when our thyroid gland is not producing enough hormones. This causes our metabolism to slow down and without enough energy our normal bodily functions begin to slow down too.
Symptoms of hypothyroidism develop slowly over time and can vary widely from person to person. They may include significant tiredness, depression, increased sensitivity to cold and unexplained weight gain. You may also experience dryness in the form of dry and thinning hair, brittle nails, flaking skin and constipation. Women of childbearing age can experience menstrual changes that could potentially affect their fertility. Seniors may experience more subtle symptoms that include confusion, decreased appetite, weight loss, decreased mobility and falls. If left untreated the symptoms of hypothyroidism will continue to progress.
Since these symptoms can also be caused by other medical conditions, the only way to diagnose hypothyroidism is to have a blood test done to measure your thyroid stimulating hormone (TSH) and your thyroxine (T4) levels. A high level of TSH and a low level of T4 generally means you have hypothyroidism.
The most effective way to treat hypothyroidism is by taking a daily prescription medication that is a man-made version of T4 known as levothyroxine. Synthroid is the most frequently prescribed brand of levothyroxine at my pharmacy, and it is available in 12 strengths to accommodate small dose changes. Some people take the same dose each day while others must take different doses on different days to keep their T4 levels within normal range.
We counsel you to take Synthroid first thing in the morning on an empty stomach with only a glass of water because having food and other beverages in your stomach can decrease the absorption of your levothyroxine dose. Ideally you should wait 30 to 60 minutes before eating or taking other medications; however, when it comes to certain medications and natural health products, the wait time is even longer.
When I look at the medicinal ingredients on my own bottle of multivitamins I can identify calcium, iron and magnesium as minerals that would decrease the absorption of Synthroid. These minerals basically stick to the levothyroxine and prevent it from being absorbed which is why we suggest you separate your multivitamin away from your Synthroid dose by at least four hours.
Now there are cases where people’s schedules do not allow them to take their Synthroid dose on an empty stomach or have it properly spaced away from medications and supplements that may affect its absorption. When this happens, the most important thing is to be consistent with the amount of food you eat and the medications you take in relation to when you take Synthroid. If the absorption of the levothyroxine is affected by the same amount each day, your prescriber should be able to make a slight adjustment to your dose to get your T4 levels back in range.
Before taking any medications or supplements with Synthroid, always discuss with your pharmacist or prescriber first to understand what the outcome may be on your levothyroxine dose and on the other medication as well. It takes approximately three to four weeks for any changes in a levothyroxine dose to balance out in our body. Therefore, if you are making a change like this you should adhere to those changes for at least one month before having bloodwork to check your T4 levels.
Erin Thompson (BSc, BScPharm) is a graduate of Dalhousie University and a community pharmacist practicing at Shoppers Drug Mart in Quispamsis N.B. Her 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 or treatment.