DYAZIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DYAZIDE (DYAZIDE).
Dyazide is a combination of hydrochlorothiazide, a thiazide diuretic that inhibits the Na+/Cl- cotransporter in the distal convoluted tubule, reducing sodium and water reabsorption; and triamterene, a potassium-sparing diuretic that blocks epithelial sodium channels in the collecting duct, reducing potassium excretion.
| Metabolism | Hydrochlorothiazide is not metabolized and is excreted unchanged by the kidneys. Triamterene is metabolized primarily in the liver via hydroxylation and conjugation, with the active metabolite hydroxytriamterene sulfate having diuretic activity. |
| Excretion | Renal: triamterene ~80% (as metabolites and parent), hydrochlorothiazide >95% unchanged. |
| Half-life | Triamterene: 1.5–2.5 hours; hydrochlorothiazide: 6–15 hours. Clinical dosing typically once daily. |
| Protein binding | Triamterene: ~67% (primarily to albumin); hydrochlorothiazide: ~40–68% (albumin). |
| Volume of Distribution | Triamterene: ~2.5 L/kg; hydrochlorothiazide: 3–4 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: triamterene ~50% (variable, 30–70%); hydrochlorothiazide ~70% (65–75%). |
| Onset of Action | Oral: diuresis begins within 2 hours, peak effect at 4–6 hours. |
| Duration of Action | Diuretic effect lasts 12–16 hours; antihypertensive effect persists up to 24 hours. |
| Action Class | Progestins (First generation) |
| Brand Substitutes | Prodin Depot 250mg Injection, HGP 250mg Injection, Gesry H 250mg Injection, Gynadream 250mg Injection, Gestimax 250mg Injection, Pregaphase 500mg Injection, Oxyron 500 Injection, Eutrion H 500mg Injection, Hergest Injection, Cantogest Injection |
1-2 capsules orally once daily; each capsule contains hydrochlorothiazide 25 mg and triamterene 50 mg.
| Dosage form | CAPSULE |
| Renal impairment | Contraindicated if GFR <30 mL/min; for GFR 30-60 mL/min, reduce dose to 1 capsule every other day or as tolerated. |
| Liver impairment | No specific Child-Pugh based guidelines; use with caution in severe hepatic impairment due to risk of hyperkalemia and fluid/electrolyte disturbances. |
| Pediatric use | Not recommended for pediatric use due to lack of safety and efficacy data. |
| Geriatric use | Start at lowest dose (1 capsule daily) with careful monitoring of electrolytes, renal function, and blood pressure due to increased risk of hyperkalemia and hypotension. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DYAZIDE (DYAZIDE).
| Breastfeeding | Contraindicated in breastfeeding. Hydrochlorothiazide excreted in milk; M/P ratio unknown. Triamterene may suppress lactation. Risk of neonatal electrolyte disturbance. |
| Teratogenic Risk | First trimester: Limited data; potential for reduced placental perfusion. Second/third trimester: Risk of fetal hypotension, oligohydramnios, and renal impairment. Avoid in pregnancy unless essential. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Anuria","Acute or chronic renal insufficiency","Hypersensitivity to hydrochlorothiazide, triamterene, or sulfonamide-derived drugs","Pre-existing hyperkalemia (serum potassium >5.5 mEq/L)","Concomitant use of other potassium-sparing diuretics, ACE inhibitors, or ARBs","Severe hepatic dysfunction"]
| Precautions | ["Hyperkalemia: Triamterene can cause hyperkalemia, especially in patients with renal impairment, diabetes, or use of other potassium-sparing drugs.","Hypokalemia: Hydrochlorothiazide can cause hypokalemia, but triamterene mitigates this risk.","Renal impairment: Avoid if creatinine clearance <30 mL/min or serum creatinine >2.5 mg/dL.","Hepatic impairment: Use with caution in patients with cirrhosis or liver disease.","Electrolyte imbalances: Monitor for hyponatremia, hypomagnesemia, and hypercalcemia.","Metabolic acidosis: Triamterene may induce metabolic acidosis.","Sulfonamide allergy: Cross-allergenicity may occur with sulfonamide-containing drugs.","Photosensitivity: Hydrochlorothiazide may cause photosensitivity reactions.","Gout or hyperuricemia: Thiazides can increase serum uric acid levels.","Diabetes: Thiazides may impair glucose tolerance."] |
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| Monitor maternal blood pressure, serum electrolytes, renal function. Serial fetal ultrasound for growth and amniotic fluid volume. Fetal heart rate monitoring if oligohydramnios detected. |
| Fertility Effects | No established effects on fertility in humans. Animal studies show no impairment at therapeutic doses. |
| Food/Dietary |
| Avoid high-potassium foods (bananas, oranges, tomatoes, spinach, potatoes, salt substitutes). Avoid excessive licorice consumption (can worsen hypokalemia). Limit sodium intake to enhance antihypertensive effect. Alcohol may potentiate orthostatic hypotension. |
| Clinical Pearls | Dyazide combines triamterene (potassium-sparing diuretic) and hydrochlorothiazide (thiazide diuretic). Monitor serum potassium closely, especially in elderly, diabetic, or renal impairment patients. Avoid in severe renal disease (CrCl <30 mL/min) or pre-existing hyperkalemia. Use with caution with ACE inhibitors, ARBs, or NSAIDs due to hyperkalemia risk. Onset of diuresis within 2 hours, peak at 4-6 hours, duration ~12 hours. |
| Patient Advice | Take exactly as prescribed; do not double doses. · Avoid potassium supplements or potassium-rich foods (e.g., bananas, oranges, salt substitutes) unless directed. · Report symptoms of hyperkalemia: muscle weakness, fatigue, numbness/tingling, irregular heartbeat. · May cause dizziness or lightheadedness; rise slowly from sitting/lying. · Avoid prolonged sun exposure; use sunscreen as thiazides increase photosensitivity. · Monitor blood pressure and weight regularly. |