THALITONE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for THALITONE (THALITONE).
Thalidone (chlorthalidone) is a thiazide-like diuretic that inhibits sodium-chloride symporter (NCC) in the distal convoluted tubule of the kidney, increasing excretion of sodium, chloride, and water. It also reduces peripheral vascular resistance and has a long duration of action (>24 hours).
| Metabolism | Minimally metabolized; primarily excreted unchanged in urine. Small degree of hepatic metabolism via unknown pathways. |
| Excretion | Primarily renal (approximately 50% unchanged); biliary/fecal elimination minor (<10%). |
| Half-life | Terminal elimination half-life is 40-60 hours, allowing once-daily dosing. |
| Protein binding | Approximately 90% bound, primarily to albumin. |
| Volume of Distribution | Vd is 3-4 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is approximately 70%. |
| Onset of Action | Diuresis begins within 2 hours after oral administration; peak effect at 4-6 hours. |
| Duration of Action | Duration of diuretic effect is approximately 24-48 hours, supporting once-daily dosing. |
Oral, 25-100 mg once daily, typically 50 mg daily.
| Dosage form | TABLET |
| Renal impairment | GFR 10-50 mL/min: administer every 24 hours; GFR <10 mL/min: avoid use or use with caution (not effective). |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B or C: use with caution due to risk of fluid and electrolyte imbalance. |
| Pediatric use | Not recommended for use in pediatric patients (safety and efficacy not established). |
| Geriatric use | Start at lowest dose (25 mg daily) due to increased sensitivity to hypotension and electrolyte disturbances; monitor renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for THALITONE (THALITONE).
| Breastfeeding | Excreted into human breast milk; M/P ratio approximately 1.5. Potential for infant sedation, neutropenia, and thrombocytopenia. Contraindicated during breastfeeding. |
| Teratogenic Risk | Thalidomide (THALITONE) is a potent human teratogen. First trimester exposure: high risk of major congenital malformations (phocomelia, limb deficiencies, anotia, microtia, facial palsy, cardiac defects, gastrointestinal atresia, renal agenesis). Second and third trimesters: risk of fetal growth restriction, neurodevelopmental effects. Contraindicated in pregnancy (category X). |
■ FDA Black Box Warning
None
| Serious Effects |
["Anuria","Renal failure (eGFR <30 mL/min/1.73m²)","Hepatic coma or pre-coma","Known hypersensitivity to sulfonamide-derived drugs"]
| Precautions | ["Electrolyte disturbances: hypokalemia, hyponatremia, hypomagnesemia, hypochloremic alkalosis","Hyperuricemia and precipitation of gout","Hyperglycemia and impaired glucose tolerance","Hyperlipidemia (increased LDL, triglycerides)","Photosensitivity and systemic lupus erythematosus exacerbation","Exacerbation of renal impairment","Orthostatic hypotension"] |
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| Fetal Monitoring |
| Maternal: pregnancy testing before and during treatment (mandatory for women of childbearing potential); complete blood counts (baseline and weekly for first 8 weeks, then monthly); liver and renal function tests; nerve conduction studies for peripheral neuropathy. Fetal: ultrasound for anomaly detection if inadvertent pregnancy occurs. |
| Fertility Effects | May cause reversible oligospermia or azoospermia in males; reduced ovarian function in females reported. No evidence of permanent infertility, but fertility preservation counseling recommended. |