A century ago, a factory worker related to the above patent might have presented to you complaining of severe headache, dizziness, and flushing every Monday. The symptoms would get better the next few days until they disappeared for the rest of the week. The following Monday, he would go through the same cycle.
Today, you might prescribe a patient the same drug as treatment or prophylaxis for acute onset chest pain.
Challenge: What drug or chemical does this refer to?
Image is in the public domain.