AQUATAG
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AQUATAG (AQUATAG).
Benzthiazide is a thiazide diuretic that inhibits the sodium-chloride symporter in the distal convoluted tubule, increasing excretion of sodium, chloride, and water.
| Metabolism | Not extensively metabolized; primarily excreted unchanged in urine. |
| Excretion | Renal: ~95% as unchanged drug; biliary/fecal: ~5% |
| Half-life | Terminal elimination half-life: 2-3 hours (prolonged in renal impairment, e.g., up to 24 hours in anuria) |
| Protein binding | ~95% bound to plasma proteins, primarily albumin |
| Volume of Distribution | 0.5 L/kg (indicates distribution primarily in extracellular fluid) |
| Bioavailability | Oral: 100% (complete absorption); Intramuscular: ~90% |
| Onset of Action | Oral: 1-2 hours; Intravenous: 15-30 minutes; Intramuscular: 30-60 minutes |
| Duration of Action | Oral: 6-8 hours; Intravenous: 4-6 hours (duration may be shorter with high doses or in patients with reduced renal function) |
25-100 mg orally once daily in the morning.
| Dosage form | TABLET |
| Renal impairment | GFR 10-50 mL/min: administer every 12-24 hours; GFR <10 mL/min: administer every 24-48 hours or avoid use. |
| Liver impairment | No specific guidelines for Child-Pugh classification; use with caution in severe hepatic impairment due to risk of electrolyte imbalances. |
| Pediatric use | Children 2-12 years: 2.5-5 mg/kg orally once daily; maximum 100 mg/day. |
| Geriatric use | Initiate at 25 mg orally once daily; adjust based on response and renal function; monitor electrolyte levels and hydration status. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AQUATAG (AQUATAG).
| Breastfeeding | Safety unknown; M/P ratio not established. |
| Teratogenic Risk | No known teratogenic risk in first trimester; limited data. In second and third trimesters, no reported fetal harm. Risk cannot be fully excluded. |
| Fetal Monitoring | Monitor maternal renal function and electrolytes; fetal ultrasound if used in pregnancy. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
["Anuria","Hypersensitivity to benzthiazide or other sulfonamide-derived drugs"]
| Precautions | ["May cause electrolyte imbalances (hypokalemia, hyponatremia, hypomagnesemia)","Can exacerbate or precipitate hyperuricemia and gout","May increase blood glucose levels in diabetic patients","Photosensitivity reactions possible","Can potentiate other antihypertensive agents"] |
| Food/Dietary | Avoid licorice (can worsen hypokalemia). Limit high-sodium foods to enhance antihypertensive effect. Grapefruit juice may increase drug absorption? (not significant with thiazides). |
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| Fertility Effects | No known effect on human fertility. |
| Clinical Pearls |
| Aquatag (benzthiazide) is a thiazide diuretic indicated for edema and hypertension. Monitor serum potassium frequently, especially in elderly or patients on digitalis. Thiazides may cause hyperglycemia and hyperuricemia; caution in diabetes and gout. Onset of diuresis is 2 hours, peak at 4-6 hours, duration 12-18 hours. Avoid in anuria or sulfonamide allergy. |
| Patient Advice | Take exactly as prescribed, usually once daily in the morning to avoid nocturia. · May cause dizziness or lightheadedness; rise slowly from sitting or lying positions. · Avoid prolonged sun exposure and use sunscreen due to photosensitivity risk. · Report symptoms of electrolyte imbalance: muscle cramps, weakness, irregular heartbeat, or excessive thirst. · Do not take potassium supplements or salt substitutes without consulting your doctor. |