NAQUA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NAQUA (NAQUA).
Inhibition of sodium-chloride symporter (NCC) in the distal convoluted tubule of the kidney, reducing sodium and chloride reabsorption and promoting diuresis.
| Metabolism | Not extensively metabolized; elimination primarily via renal tubular secretion and glomerular filtration. |
| Excretion | Primarily renal elimination; approximately 60-80% excreted unchanged in urine via tubular secretion; minor biliary/fecal excretion (<10%). |
| Half-life | Terminal elimination half-life is 6-12 hours; prolonged in renal impairment (up to 20-30 hours) or heart failure due to reduced renal perfusion. |
| Protein binding | Highly protein bound (>95%), primarily to albumin. |
| Volume of Distribution | Volume of distribution is 0.2-0.3 L/kg, indicating limited extravascular distribution (mainly in extracellular fluid). |
| Bioavailability | Oral bioavailability is approximately 60-70%; food reduces absorption rate but not extent. |
| Onset of Action | Oral: diuresis begins within 1 hour; IV: diuresis onset within 15-30 minutes. |
| Duration of Action | Duration of diuresis is 6-12 hours after oral dose; IV duration is 2-4 hours. Clinical effect may persist beyond pharmacokinetic half-life due to prolonged renal action. |
Oral: 5-10 mg once daily, preferably in the morning. Maximum dose 20 mg/day.
| Dosage form | TABLET |
| Renal impairment | GFR 30-60 mL/min: 5 mg once daily. GFR <30 mL/min: not recommended due to reduced efficacy. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: 2.5 mg once daily. Child-Pugh C: contraindicated. |
| Pediatric use | 0.2 mg/kg/day as a single dose, maximum 5 mg/day. |
| Geriatric use | Start at 2.5 mg once daily; titrate cautiously due to increased risk of electrolyte imbalance and hypotension. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NAQUA (NAQUA).
| Breastfeeding | Trichlormethiazide is excreted into breast milk in small amounts. The M/P ratio is not established, but thiazide diuretics generally have low milk concentrations. However, they may suppress lactation, especially at high doses. Potential effects on the infant include electrolyte imbalances and idiosyncratic reactions. Use during breastfeeding is not recommended; alternative diuretics are preferred. |
| Teratogenic Risk | Naqua (trichlormethiazide) is a thiazide diuretic. In pregnancy, use is generally avoided, especially during the first trimester, due to potential for fetal harm. First trimester: There is limited human data; animal studies have shown evidence of fetotoxicity (e.g., skeletal anomalies) at high doses. Second and third trimesters: Thiazides can cause placental hypoperfusion, fetal electrolyte disturbances, and neonatal thrombocytopenia. They may also reduce maternal blood volume, potentially impairing fetal growth. Crosses placenta. Contraindicated in preeclampsia. |
■ FDA Black Box Warning
None
| Serious Effects |
Anuria, hypersensitivity to trichlormethiazide or sulfonamide-derived drugs, severe renal impairment (creatinine clearance <30 mL/min), hepatic coma or pre-coma.
| Precautions | Risk of hypokalemia, hyponatremia, hypochloremia, metabolic alkalosis, hypomagnesemia, hyperuricemia, and hyperglycemia; may precipitate hepatic coma in patients with hepatic cirrhosis; can cause photosensitivity; monitor for hypersensitivity reactions. |
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| Fetal Monitoring | Monitor serum electrolytes (especially potassium, sodium, chloride), renal function (BUN, creatinine), blood pressure, and uric acid levels. In pregnancy, additional monitoring includes fetal growth assessment (ultrasound) due to potential placental insufficiency, and neonatal platelet count if used near term. Observe for signs of maternal volume depletion and electrolyte disturbances. |
| Fertility Effects | No specific studies on trichlormethiazide and human fertility. Thiazide diuretics are not known to impair fertility; however, they may cause electrolyte disturbances or metabolic effects that could theoretically affect reproductive function. In animal studies, no adverse effects on fertility were reported at clinical doses. |