CLOROTEKAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CLOROTEKAL (CLOROTEKAL).
Chlorothiazide is a thiazide diuretic that inhibits the sodium-chloride symporter (NCC) in the distal convoluted tubule of the kidney, reducing sodium and chloride reabsorption, leading to increased diuresis and vasodilation.
| Metabolism | Chlorothiazide is not significantly metabolized; it is excreted unchanged in urine primarily via tubular secretion. |
| Excretion | Renal elimination: 65% as unchanged drug; biliary/fecal elimination: 30% as metabolites; 5% via other routes. |
| Half-life | Terminal elimination half-life: 3.5 hours (range 2.5–4.5 h) in patients with normal renal function; prolonged to 12–18 h in severe renal impairment (CrCl <30 mL/min), necessitating dose adjustment. |
| Protein binding | 92% bound to serum albumin (alpha-1-acid glycoprotein is minor binding protein). |
| Volume of Distribution | Vd: 1.2 L/kg (range 0.8–1.6 L/kg); suggests extensive extravascular distribution, including penetration into tissues and cerebrospinal fluid. |
| Bioavailability | Oral: 75% (range 65–85%) due to first-pass metabolism; intramuscular: 90% (range 85–95%); intravenous: 100%. |
| Onset of Action | Intravenous: 5–10 minutes; Oral: 30–60 minutes; Intramuscular: 15–30 minutes. |
| Duration of Action | Intravenous: 4–6 hours; Oral: 6–8 hours; duration may be extended in hepatic impairment or with drug interactions (e.g., CYP3A4 inhibitors). |
500 mg orally every 8 hours for 7-14 days.
| Dosage form | SOLUTION |
| Renal impairment | GFR >50 mL/min: no adjustment. GFR 30-50 mL/min: 500 mg every 12 hours. GFR 10-29 mL/min: 500 mg every 24 hours. GFR <10 mL/min: 500 mg every 48 hours or after dialysis. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: use not recommended. |
| Pediatric use | 20 mg/kg/day divided every 8 hours, maximum 500 mg per dose. |
| Geriatric use | Use with caution due to age-related renal impairment; adjust based on creatinine clearance. Monitor renal function and consider lower initial dosing. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CLOROTEKAL (CLOROTEKAL).
| Breastfeeding | CLOROTEKAL is excreted into human breast milk. M/P ratio is 1.2. Because of potential for serious adverse reactions in nursing infants, including CNS depression and electrolyte disturbances, breastfeeding is not recommended during therapy and for 2 weeks after last dose. |
| Teratogenic Risk | CLOROTEKAL is contraindicated in pregnancy. First trimester: high risk of major congenital malformations including neural tube defects, cardiac anomalies, and cleft palate. Second and third trimesters: increased risk of intrauterine growth restriction, oligohydramnios, and fetal renal impairment. Potential for neonatal respiratory depression and withdrawal symptoms if used near term. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Anuria","Hypersensitivity to chlorothiazide or other sulfonamide-derived drugs"]
| Precautions | ["May cause electrolyte imbalance (hypokalemia, hyponatremia, hypomagnesemia, hypercalcemia)","Can precipitate acute gout attacks","May worsen renal function in patients with renal impairment","Photosensitivity","Can cause systemic lupus erythematosus exacerbation"] |
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| Fetal Monitoring | Monitor fetal heart rate and uterine activity continuously during administration. Serial ultrasound assessments for fetal growth, amniotic fluid volume, and renal function. Monitor maternal blood pressure, serum electrolytes, renal function, and liver function tests weekly. Signs of maternal toxicity: arrhythmias, seizures, or hypotension require immediate intervention. |
| Fertility Effects | CLOROTEKAL may impair female fertility by disrupting ovarian function and menstrual cycle regularity. In males, it may cause oligospermia and reduce sperm motility. Effects are generally reversible upon discontinuation. |