What is the effect of Maxzide (Triamterene and Hydrochlorothiazide)?

From the Guidelines

Maxzide should be used with caution in patients with hypertension, and the typical starting dose is 37.5-25 mg once daily, with monitoring of potassium levels and regular blood tests to prevent potential side effects, as recommended by the 2017 ACC/AHA guideline 1.

Key Considerations

• Maxzide is a combination of hydrochlorothiazide, a thiazide diuretic, and triamterene, a potassium-sparing diuretic, which helps prevent potassium loss and reduces blood volume to lower blood pressure.
• The medication is primarily used to treat high blood pressure (hypertension) and edema (fluid retention), with a typical starting dose of Maxzide 37.5-25 mg once daily, which may be increased to Maxzide 75-50 mg if needed.
• Patients should avoid potassium supplements and high-potassium foods unless directed by their doctor, and those with kidney disease, liver problems, or diabetes should use this medication with caution.

Potential Side Effects

• Common side effects include increased urination, dizziness, headache, and electrolyte imbalances.
• Monitoring of potassium levels is crucial, as too much potassium can be dangerous.
• Regular blood tests are recommended to monitor electrolytes and kidney function during treatment.

Guideline Recommendations

• The 2017 ACC/AHA guideline recommends thiazide or thiazide-type diuretics, calcium channel blockers (CCBs), angiotensin converting enzyme inhibitors (ACEIs), and angiotensin receptor blockers (ARBs) as initial drug choices for hypertension treatment 1.
• Chlorthalidone and indapamide, thiazide-like diuretics, have a longer duration of action compared to thiazide diuretics and are the preferred diuretics for management of hypertension, as stated in the 2021 guideline-driven management of hypertension update 1.

From the FDA Drug Label

Triamterene can cause mild nitrogen retention, which is reversible upon withdrawal of the drug, and is seldom observed with intermittent (every-other-day) therapy. Hyperkalemia will rarely occur in patients with adequate urinary output, but it is a possibility if large doses are used for considerable periods of time. If hyperkalemia is observed, Triamterene should be withdrawn. The main side effects of Maxzide (triamterene) include:

• Hyperkalemia: a possibility if large doses are used for considerable periods of time
• Mild nitrogen retention: reversible upon withdrawal of the drug
• Metabolic acidosis: due to a decreasing alkali reserve
• Megaloblastosis: in cases where folic acid stores have been depleted
• Elevated uric acid: especially in persons predisposed to gouty arthritis
• Renal stones: in association with other calculus components 2 The recommended course of action in case of overdose is:
• Immediate evacuation of the stomach through emesis and gastric lavage
• Careful evaluation of the electrolyte pattern and fluid balance
• Possible benefit to dialysis in cases of overdosage 2

From the Research

Maxzide Overview

• Maxzide is a combination formulation of triamterene and hydrochlorothiazide, used to treat mild to moderate hypertension 3, 4.
• The combination of potassium-sparing diuretics with hydrochlorothiazide is extensively used by hypertensive patients 3.

Bioavailability and Efficacy

• The bioavailability of Maxzide tablets is higher compared to Dyazide capsules, with the hydrochlorothiazide component being absorbed to the same extent as single-entity hydrochlorothiazide tablets 3.
• Maxzide tablets offer the advantages of once-a-day dosing and significant reductions in blood pressures, especially in some patients who had remained hypertensive while receiving Dyazide 3, 4.

Comparison with Other Antihypertensive Therapies

• Combination antihypertensive therapy, including hydrochlorothiazide, is more effective than monotherapy in achieving target blood pressure goals 5, 6, 7.
• The use of calcium channel blockers, beta-blockers, and thiazide diuretics, such as hydrochlorothiazide, is recommended in patients with hypertension and coronary artery disease 6.
• Triple fixed-dose combination therapy with an angiotensin II receptor blocker, a calcium channel blocker, and a thiazide diuretic, such as hydrochlorothiazide, is considered a rational combination for treating uncontrolled hypertensive patients 7.

Safety and Tolerability

• Maxzide tablets have been shown to be safe and well-tolerated, with no clinically significant changes in blood urea nitrogen, creatinine, or uric acid levels, and no development of hyperkalemia or hypokalemia 3, 4.
• The combination of triamterene and hydrochlorothiazide in Maxzide has been found to maintain normal serum electrolyte values, including potassium, with minor changes in the levels of uric acid, creatinine, and blood urea nitrogen 4.