Hello! Thank you for your question on HCM! I understand your concern. The loss of the Sandomigran effect on you may be related to a phenomena called tolerance. I would like to explain that in some patients the chronic intake of Sandomigran has shown to cause tolerance. This means that higher doses are needed progressively to reach the same effect, until it has no effect any more on the control of headaches. This drug should be stopped slowly, by reducing slowly the dose until you stop taking it. This is done in order to avoid withdrawal symptoms from an abrupt stopping. I would recommend you to consult with your attending physician and consider the possibility to start on another therapy for the prevention of migraine attacks like : topiramate or amytriptiline. Hope to have been of help! Greetings! Dr. Aida