Can hydrochlorothiazide cause sleep apnea ? can any docs explain?

No: HCTZ (hydrochlorothiazide) works on kidneys to get excess sodium and other minerals out so Blood pressure go's down as sodium=salt, is a major contributor to high BP. Sleep apnea can also contribute to highBP, and if consistently unchecked can do a lot of havoc to the body which will usually be over a long time. Main reason is because less oxygen placing more strain on the organs-simple explanation.