Maxzide Lowest Dose
The lowest available dose of Maxzide is 37.5 mg triamterene/25 mg hydrochlorothiazide (half-tablet formulation). 1
Available Formulations
Maxzide is manufactured in two fixed-dose combinations:
- Maxzide-25: 37.5 mg triamterene/25 mg hydrochlorothiazide (the lowest dose)
- Maxzide: 75 mg triamterene/50 mg hydrochlorothiazide (standard dose)
The 37.5/25 mg formulation is specifically listed in the JNC 7 guidelines as one of the available combination diuretic products 1.
Clinical Context for Dosing
When initiating potassium-sparing diuretic therapy, starting with the lowest dose is strongly recommended to minimize the risk of hyperkalemia, particularly in patients with:
- Chronic kidney disease (eGFR <45 mL/min) 2, 3
- Concurrent ACE inhibitor or ARB therapy 2, 3
- Baseline elevated serum potassium 2
Monitoring Requirements
After initiating the lowest dose of Maxzide:
- Check serum potassium and creatinine within 5-7 days 2
- Continue monitoring every 5-7 days until values stabilize 2
- Then monitor every 3-6 months during maintenance therapy 2
Dose Titration
If additional diuretic effect is needed after starting with the 37.5/25 mg dose:
- The dose can be increased to the standard Maxzide formulation (75/50 mg) once daily
- Maximum recommended dose is 75 mg triamterene/50 mg hydrochlorothiazide daily 4, 3
Important Caveats
Avoid potassium-sparing diuretics entirely during initiation of ACE inhibitor or ARB therapy 2. They should only be added if hypokalaemia persists despite ACE inhibitor/ARB and loop or thiazide diuretic therapy 2.
The combination should be avoided in patients with significant renal dysfunction (eGFR <45 mL/min) due to high risk of life-threatening hyperkalemia 5.