Synthroid® and Zoloft® are used for different conditions, but they are linked in various ways. Synthroid® is used to treat hypothyroidism, or an underactive thyroid. Zoloft® treats conditions such as anxiety and depression and other conditions caused by a chemical imbalance in the brain. Both conditions often occur together, and sometimes an underactive thyroid can lead to anxiety in some individuals.
Many people take both Synthroid® and Zoloft® for thyroid disorder and depression or anxiety. Both conditions can affect mood, energy levels, and hormones throughout the body. They are also heavily linked because hypothyroidism can eventually lead to anxiety symptoms if left untreated. In some cases, someone may be diagnosed with anxiety when he or she may actually suffer from a thyroid disorder.
There are no known drug interactions between Synthroid® and Zoloft®. Synthroid® contains hormones which are normally present in the body anyway, so it is a replacement medication. Zoloft® helps to regulate naturally occurring chemicals in the brain. They can normally be taken together with no adverse reactions. That said, both medications have side effects associated with their use, and using them together may make certain effects more likely to occur.
Synthroid® and Zoloft® can both cause insomnia and digestive upset, so these conditions may be more pronounced in those taking both medications. Zoloft® can also lead to suicidal thought and behaviors in some individuals. Synthroid® can cause fever, irritability, menstrual changes, and appetite or weight changes. Both can cause headaches.
The conditions Synthroid® and Zoloft® treat often mimic each other in symptoms. Hypothyroidism and a chemical imbalance in the brain can both cause irritability, appetite changes, depression, nervousness, anxiety, and fatigue. Some patients may have both at once, which can compound symptoms. Others may be diagnosed with one condition when they have the other. In these situations one medication can generally be discontinued once the source of symptoms is found.
Patients who believe they have either a thyroid disorder or anxiety or depression should consult with their doctors. Long-term issues can arise with untreated hypothyroidism, such as severe depression, infertility, and weight gain. Anxiety disorders can cause severe emotional upset and may worsen unless treatment is sought.