How long does it take for medication to dissolve the clot that caused pulmonary embolism?

Weeks or months. It can take weeks or months for a pulmonary embolism to totally dissolve. However there is typically more and more relief as the clot gets smaller from treatment. Symptoms from a pulmonary embolism, such as shortness of breath or mild pain or pressure in your chest, can last 6 weeks or longer. .