Hello, Welcome to HCM and thanks for your query. I appreciate your concern for your husband. I agree with you that Bisprolol HCTZ is the probable cause. Hydrochlorothiazide is a diuretic which leads to loss of electrolytes and fluids and can produce tiredness. If he does not have hypertension, it is not required. Bisprolol in small doses help control symptoms of sympathetic over activity associated with anxiety. In larger doses, Bisprolol also can be the cause of tiredness. If bisprolol is not available by itself, an alternative would be small doses of propranolol. My patients respond very well. I am available if you have more queries. Take care Dr. Noble Zachariah