NAQUIVAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NAQUIVAL (NAQUIVAL).
NAQUIVAL (trichlormethiazide) is a thiazide diuretic that inhibits the sodium-chloride symporter (NCC) in the distal convoluted tubule of the nephron, reducing electrolyte reabsorption and increasing urine output, thereby lowering blood pressure and reducing edema.
| Metabolism | Trichlormethiazide is not extensively metabolized; it is primarily eliminated unchanged by the kidneys via glomerular filtration and active tubular secretion. Small amounts may undergo hepatic metabolism, but specific enzymes are not well characterized. |
| Excretion | Renal: 50-60% as unchanged drug; fecal: <10% (biliary); remainder as metabolites (80% renal, 10% fecal). |
| Half-life | Terminal elimination half-life: 14-16 hours (healthy adults). Extended to 26-35 hours in heart failure or hepatic cirrhosis due to reduced clearance. |
| Protein binding | 99% bound, primarily to albumin and α1-acid glycoprotein. |
| Volume of Distribution | Vd: 0.25-0.35 L/kg (3-4 L total). Reflects high plasma binding and limited extravascular distribution. |
| Bioavailability | Oral: 70-90% (well absorbed; food may reduce rate but not extent). Rectal: 50-70% (variable). |
| Onset of Action | Oral: Diuresis begins within 1 hour, peaks at 2-4 hours. IV: Diuresis within 5-15 minutes. |
| Duration of Action | Oral: Duration of diuretic effect 6-12 hours. IV: 2-4 hours. Clinical note: Antihypertensive effect persists for 24 hours with chronic dosing. |
Adults: 0.1 mg/kg IV bolus, then 0.1 mg/kg/hour continuous IV infusion, titrated to clinical response. Maximum 0.5 mg/kg/hour.
| Dosage form | TABLET |
| Renal impairment | GFR 30-60 mL/min: reduce initial bolus to 0.05 mg/kg and infusion to 0.05 mg/kg/hour. GFR <30 mL/min: avoid use or use with extreme caution. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: contraindicated. |
| Pediatric use | Children >1 year: 0.05-0.1 mg/kg IV bolus, then 0.05-0.1 mg/kg/hour continuous infusion; maximum infusion rate 0.2 mg/kg/hour. Neonates: not recommended. |
| Geriatric use | Start at low end of dosing range (0.05 mg/kg bolus, 0.05 mg/kg/hour infusion); monitor renal function and electrolytes closely; increased risk of hypotension and bradycardia. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NAQUIVAL (NAQUIVAL).
| Breastfeeding | Methyclothiazide is present in human milk in low concentrations; M/P ratio not available. May suppress lactation. Use with caution, monitor infant for signs of electrolyte disturbance. Alternative diuretics preferred during breastfeeding. |
| Teratogenic Risk | NAQUIVAL (methyclothiazide) is a thiazide diuretic. First trimester: Limited human data, animal studies not adequate, risk cannot be excluded. Potential for teratogenicity not established. Second and third trimesters: Associated with maternal hypovolemia, electrolyte imbalances, and placental hypoperfusion; may cause fetal jaundice, thrombocytopenia, and electrolyte disturbances. Use only if clearly needed. |
■ FDA Black Box Warning
No specific black box warning.
| Serious Effects |
["Anuria (absolute)","Known hypersensitivity to trichlormethiazide or other sulfonamide-derived drugs (relative)","Severe renal impairment (relative, unless as part of careful management)","Severe hepatic impairment with hepatic coma (relative)"]
| Precautions | ["Electrolyte imbalances: monitor serum potassium, sodium, magnesium, and calcium","Hypokalemia can increase risk of cardiac arrhythmias, especially in patients on digoxin","Hypovolemia and dehydration, particularly in elderly or volume-depleted patients","Use with caution in patients with hepatic impairment due to risk of hepatic encephalopathy","May cause acute angle-closure glaucoma due to sulfonamide class effect","Exacerbation or activation of systemic lupus erythematosus","Hyperuricemia and potential gout"] |
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| Fetal Monitoring | Monitor maternal blood pressure, serum electrolytes (especially potassium, sodium, chloride), renal function, and fluid balance. Assess fetal growth and amniotic fluid volume via ultrasound if used chronically. Monitor for signs of fetal distress or oligohydramnios. |
| Fertility Effects | No known direct effects on fertility. However, electrolyte disturbances or dehydration from chronic use may indirectly affect reproductive function. Animal studies have not shown impaired fertility. |