Thank you for the query. I would like to know your age and gender. Hyponatremia (low sodium levels in blood) can arise due to a number of causes like congestive cardiac failure/liver disease (hypervolemic fluid status), SIADH (euvolemic fluid status) and severe diarrhoea (hypovolemic fluid status). However, one of the commonest cause is intake of antihypertensive drugs like diuretics - hydrochlorthiazide and frusemide. Since, you have a history of hypertension, I would like to know your drug regimen. If it comprises of diuretics (like the ones mentioned above), it may be a cause for your hyponatremia. You can go for extra salt in diet and certain amount of fluid restriction which might help. In case you are on diuretics, these may have to be substituted for another class of drugs for hypertension. If you are symptomatic due to hyponatremia (for eg weakness, slowness, confusion etc), you may need to visit your physician for a thorough physical checkup and further investigations. In some cases hypertonic saline may need to transfused, in a hospital setting, though in your case, it is not required at this moment. Vaptans are a group of drugs administered for Hyponatremia (hypervolemic and euvolemic) under a physician s guidance. Hope this helps you out.