From the Guidelines

Thiazide-type diuretics, such as chlorthalidone, are the best initial medication for diastolic hypertension.

The American College of Cardiology/American Heart Association task force on clinical practice guidelines recommends thiazide-type diuretics as a first-line treatment for hypertension due to their effectiveness in preventing cardiovascular disease 1.
Clinical trials have shown that thiazide-type diuretics, such as chlorthalidone, are superior to other agents in preventing major forms of cardiovascular disease and are less expensive 1.
The European Society of Hypertension and the European Society of Cardiology recommend using a combination of two or more drugs, including a blocker of the renin-angiotensin system, to lower blood pressure in diabetic patients, but thiazide-type diuretics can be used as initial therapy 1.
The optimal diastolic blood pressure to be achieved by treatment is not clear, but a diastolic pressure of less than 70 mmHg may identify a high-risk group, possibly due to overtreatment 1.

The choice of initial medication should be tailored to individual patient characteristics, including underlying cardiovascular risk and comorbidities.
Combination therapy may be necessary to achieve blood pressure control, especially in older patients or those with difficult-to-control hypertension.

From the Research

Thiazide diuretics, such as chlortalidone or hydrochlorothiazide, are often considered the first-line treatment for hypertension, including diastolic hypertension, due to their efficacy in reducing blood pressure and preventing cardiovascular complications 2, 3, 4.
Angiotensin-converting enzyme (ACE) inhibitors, such as lisinopril, and angiotensin receptor blockers (ARBs) are also effective in treating diastolic hypertension and are often used as first-line or second-line therapy 5, 3, 6.
Calcium channel blockers, such as amlodipine, and beta-blockers may also be used to treat diastolic hypertension, although they may not be as effective as thiazide diuretics or ACE inhibitors in reducing blood pressure and preventing cardiovascular complications 2, 5, 3.
The choice of medication should be based on individual patient characteristics, such as the presence of comorbidities, and the potential for adverse effects 2, 3, 4.

Thiazide diuretics have been shown to be effective in reducing all-cause mortality, cardiovascular morbidity and mortality, and cerebrovascular morbidity and mortality in patients with diastolic hypertension 2, 4.
ACE inhibitors and ARBs have also been shown to be effective in reducing blood pressure and preventing cardiovascular complications in patients with diastolic hypertension 5, 3, 6.
Calcium channel blockers and beta-blockers may be less effective in reducing blood pressure and preventing cardiovascular complications, but may still be useful in certain patient populations 2, 5, 3.

Lifestyle modifications, such as dietary changes and increased physical activity, should be recommended to all patients with diastolic hypertension, regardless of the chosen medication 3, 6.
The potential for adverse effects, such as hyperglycemia and diabetes with thiazide diuretics, should be considered when choosing a medication 2, 3, 4.
The presence of comorbidities, such as kidney disease or heart failure, should be taken into account when choosing a medication 5, 3, 6.