DIUCARDIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DIUCARDIN (DIUCARDIN).
Thiazide diuretic that inhibits the Na+/Cl- symporter in the distal convoluted tubule, reducing sodium and chloride reabsorption, leading to increased diuresis and vasodilation.
| Metabolism | Primarily metabolized via cytochrome P450 (CYP3A4) and other minor pathways; undergoes hepatic metabolism to inactive metabolites. |
| Excretion | Primarily renal excretion: approximately 60-70% of the dose is excreted unchanged in urine within 24 hours. Biliary/fecal elimination accounts for about 20-30%, with some enterohepatic circulation. |
| Half-life | Terminal elimination half-life is approximately 18-24 hours in normal renal function. This prolongs significantly in renal impairment, requiring dose adjustment. |
| Protein binding | Approximately 95-98% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is about 3-4 L/kg, indicating extensive tissue distribution. Clinical meaning: large Vd suggests drug penetrates well into interstitial and intracellular spaces. |
| Bioavailability | Oral bioavailability is 60-80% due to first-pass metabolism. Intravenous bioavailability is 100%. |
| Onset of Action | Oral: Onset of diuresis occurs within 1 hour, with peak effect at 2-4 hours. Intravenous: Onset within 15 minutes, peak at 30 minutes. |
| Duration of Action | Duration is 6-12 hours after oral administration. The antihypertensive effect lasts 24 hours with once-daily dosing. |
| Molecular Weight | 390.45 |
Hydrochlorothiazide 25-50 mg orally once daily, titrated based on response. Maximum dose 100 mg/day.
| Dosage form | TABLET |
| Renal impairment | GFR 30-50 mL/min: reduce dose by 50%; GFR <30 mL/min: avoid use (ineffective). |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: avoid use due to risk of electrolyte disturbances. |
| Pediatric use | Children >6 months: 1-2 mg/kg/day orally in 2 divided doses; maximum 50 mg/day. |
| Geriatric use | Start with 12.5-25 mg orally once daily; monitor electrolytes and renal function closely; avoid doses >50 mg/day. |
| 1st trimester | Risk in first trimester is unknown; insufficient human data. Use only if benefit outweighs risk. |
| 2nd trimester | Use with caution; may cause fetal harm. Monitor amniotic fluid and fetal growth. |
| 3rd trimester | Contraindicated in third trimester; may cause oligohydramnios and neonatal renal impairment. |
Clinical note
Comprehensive clinical and safety monograph for DIUCARDIN (DIUCARDIN).
| Placental transfer | Crosses placenta; evidence from animal studies and limited human data. |
| Breastfeeding | Diucardin is excreted in breast milk; may affect lactation and cause adverse effects in infant. Use with caution, especially in neonates. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
AnuriaHypersensitivity to Diucardin or sulfonamidesSevere renal impairment (CrCl < 30 mL/min)Third trimester of pregnancy
| Precautions | Electrolyte imbalances (hypokalemia, hyponatremia, hypomagnesemia), Hyperuricemia and potential gout attacks, Sulfonamide allergy cross-sensitivity, Photosensitivity reactions, Systemic lupus erythematosus exacerbation |
| Food/Dietary | Avoid high-sodium foods as they reduce antihypertensive efficacy. Grapefruit juice may increase bioavailability of some thiazides; interaction not specifically reported for hydroflumethiazide. Calcium-rich foods may alter calcium excretion; no significant restriction needed. |
Loading safety data…
| L3 (Moderately Safe) - limited data; weigh risks and benefits. |
| Teratogenic Risk | First trimester: Limited human data; animal studies show no teratogenicity. Avoid use unless benefit outweighs risk. Second/third trimester: Possible fetal hypotension, electrolyte disturbances (e.g., hypokalemia), hyponatremia, and decreased amniotic fluid volume. Avoid use for pregnancy-induced hypertension. |
| Fetal Monitoring | Maternal: Blood pressure, serum electrolytes (especially potassium, sodium), renal function, fluid balance. Fetal: Ultrasonography to assess amniotic fluid volume and fetal growth; non-stress test or biophysical profile as indicated. |
| Fertility Effects | No known adverse effects on human fertility. Animal studies showed no impairment. |
| Clinical Pearls |
| Diucardin (hydroflumethiazide) is a thiazide diuretic. Monitor serum potassium; hypokalemia increases digoxin toxicity risk. Avoid in severe renal impairment (CrCl <30 mL/min). May cause hyperglycemia, hyperuricemia. Onset of diuresis within 2 hours, peak at 4 hours, duration 12-18 hours. |
| Patient Advice | Take in the morning to avoid nighttime urination. · Avoid prolonged sun exposure; may cause photosensitivity. · Report muscle cramps, weakness, or irregular heartbeat. · Limit alcohol intake; may enhance orthostatic hypotension. · Do not use potassium supplements or salt substitutes without consulting prescriber. |