From the FDA Drug Label
For Control of Hypertension: The adult initial dose of hydrochlorothiazide capsules is one capsule given once daily whether given alone or in combination with other antihypertensives. Total daily doses greater than 50 mg are not recommended. The maximum recommended dose of hydrochlorothiazide (HCTZ) for hypertension is 50 mg per day 1.
From the Research
The maximum recommended dose of hydrochlorothiazide (HCTZ) for hypertension is 50 mg daily. Most patients typically start at a lower dose of 12.5 to 25 mg daily, with dose adjustments made based on blood pressure response 2. HCTZ is a thiazide diuretic that works by increasing sodium and water excretion in the kidneys, which reduces blood volume and subsequently lowers blood pressure. The full antihypertensive effect may take several weeks to develop. Doses higher than 50 mg daily generally do not provide additional blood pressure lowering benefits but significantly increase the risk of side effects such as electrolyte imbalances (particularly hypokalemia), hyperglycemia, and hyperuricemia.
Some key points to consider when prescribing HCTZ include:
- Starting with a low dose and titrating up as needed to minimize side effects
- Monitoring electrolyte levels, particularly potassium, to prevent hypokalemia
- Advising patients to take the medication in the morning to avoid nighttime urination
- Considering the addition of a different class of antihypertensive medication for patients with inadequate blood pressure control on the maximum HCTZ dose, rather than exceeding the 50 mg daily limit 2.
It's also important to note that thiazides have a greater effect on systolic than on diastolic blood pressure, which can lead to a reduction in pulse pressure 2. Overall, the use of HCTZ should be tailored to the individual patient's needs and response to treatment, with careful consideration of the potential benefits and risks.