These medications may also be used to treat thyroid cancer or other thyroid conditions. The long-term safety of levothyroxine is well established. Typically side effects only occur due to overdosage of the medication. For more specific information, consult with your doctor or pharmacist for guidance based on your specific condition and current medications.
My neighbor just puts 3-4 gal of bleach down the pipe, then waits 24 hrs. Then runs water through all the fixtures until the bleach smell is gone. He said it usually last for 1-1/2 years. Our water is relatively soft, but does have a bit of iron in it.
A slight chlorine odor should be noticeable in the water, if not, add another dose of bleach and allow the water to stand another 15 minutes. Tightly close the container using the original cap. Be careful not to contaminate the cap by touching the inside of it with your finger.