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.
Leave the bleach to sit for at least 15 minutes, then flush. Flush the toilet and wait for the tank to refill with fresh water. The water level in the toilet bowl will drop, then rise to its normal level before the tank is filled. Once the tank is refilled, flush the toilet again.