PRM Pharma, LLC announced today that the U.S. Food and Drug Administration (FDA) has approved HemiClor (12.5 mg chlorthalidone) tablets for the treatment of hypertension in adults. This approval marks the introduction of the first low-dose chlorthalidone formulation in the United States, addressing a significant gap in hypertension management options.
Until now, chlorthalidone has only been available in the U.S. in higher doses of 25 mg and 50 mg, despite clinical guidelines recommending 12.5 mg as the optimal starting dose for many patients. The new formulation is expected to be available in pharmacies nationwide beginning in May 2025.
Clinical Significance and Evidence Base
Chlorthalidone, a thiazide-like diuretic, has been extensively studied for decades in hypertension treatment. The 2017 ACC/AHA Guideline for the Prevention, Detection, Evaluation and Management of High Blood Pressure in Adults recognizes chlorthalidone as the preferred diuretic due to its prolonged half-life and demonstrated cardiovascular outcome benefits.
The efficacy of the 12.5 mg dose is supported by landmark clinical trials including the ALLHAT and SHEP studies, both sponsored by the National Heart, Lung, and Blood Institute. These trials showed that stepped-care treatment strategies beginning with 12.5 mg of chlorthalidone effectively reduced the risk of cardiovascular events.
"Chlorthalidone has played a key role in hypertension treatment strategies for decades," said William B. White, M.D., Professor Emeritus at the University of Connecticut School of Medicine and past president of the American Society of Hypertension. "Having access to a 12.5 mg dose in the U.S. may offer clinicians additional flexibility when initiating therapy and aligns with current treatment recommendations for many adult patients with stage 1 or stage 2 hypertension."
Potential Benefits of Lower Dosing
The introduction of HemiClor addresses an important clinical need by providing a dosage that aligns with guideline recommendations. The lower dose may help clinicians better individualize therapy while potentially reducing the risk of dose-related adverse effects.
Metabolic adverse effects associated with chlorthalidone, such as hypokalemia and hyperuricemia, are known to be dose-related. The availability of a lower starting dose may help mitigate these risks when initiating treatment, particularly in vulnerable populations such as elderly patients who are more susceptible to dose-related adverse effects.
Joseph T. McDevitt, President and CEO of PRM Pharma, LLC, emphasized the company's mission: "We are proud to introduce HemiClor as a new treatment option for adults with hypertension. Our mission is to address unmet clinical needs by developing low-dose pharmaceutical products that support evidence-based care. Lower effective doses may offer a more individualized approach to initiating therapies, particularly for elderly patients."
Safety Considerations and Monitoring
As with all thiazide-like diuretics, healthcare providers should be aware of important safety considerations when prescribing HemiClor. The drug is contraindicated in patients with anuria or known hypersensitivity to chlorthalidone or sulfonamide-derived drugs.
The most common adverse reactions observed with chlorthalidone include electrolyte imbalance (particularly hypokalemia), dizziness, and gastrointestinal discomfort. Periodic monitoring of serum electrolytes is recommended for patients taking the medication.
Additionally, chlorthalidone may increase blood sugar levels, affect diabetes control, and cause changes in the need for diabetes medication. It may also potentiate the effects of other antihypertensive agents and interact with lithium, antidiabetics, or NSAIDs.
Hypertension Burden and Treatment Landscape
Hypertension remains one of the most prevalent chronic conditions in the United States, affecting approximately 116 million adults according to the Centers for Disease Control and Prevention. Despite advances in treatment options, blood pressure control rates remain suboptimal, with only about 24% of those with hypertension having their condition under control.
The approval of HemiClor provides clinicians with an additional tool that aligns with evidence-based guidelines. The medication can be used either to initiate antihypertensive therapy or as add-on therapy when additional blood pressure reduction is needed.
The indication for HemiClor notes that lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions—benefits that have been demonstrated in controlled trials of antihypertensive drugs from various pharmacologic classes, including chlorthalidone.
With this approval, healthcare providers now have access to a guideline-recommended starting dose of a proven antihypertensive agent, potentially improving treatment optimization and patient outcomes in hypertension management.
