A patient with a diastolic blood pressure of 55 mmHg and a systolic blood pressure of 95 mmHg is not normal and is considered hypotensive. It is recommended that the patient have an ambulatory blood pressure monitor, if necessary, to assess the overall blood pressure over a 24-hour period, and then further investigate the cause of the drop in blood pressure. It may be caused by an overdose of antihypertensive medication or it may be caused by a family history of hypotension. In cases of familial hypotension, there are often no uncomfortable symptoms and the patient has tolerated the low blood pressure. Such patients do not require special treatment. In some patients, hypotension may be caused by a recent cold, frequent nausea, vomiting, or diarrhea, and should be treated in combination with rehydration.