Dosing and uses of Hygroton, Thalitone (chlorthalidone)
Adult dosage forms and strengths
tablet
- 15mg
- 25mg
- 50mg
- 100mg
Hypertension
25-100 mg/day PO; usual range, 12.5-25 mg/day
Edema
50-100 mg/day PO or 100 mg PO every other day; not to exceed 200 mg/day
Heart Failure
12.5-25 mg/day PO; not to exceed 100 mg/day
Dosing Considerations
Administered in the morning with food
Overdose management
- Normal saline may be used for volume replacement
- Dopamine or norepinephrine may be used to treat hypotension
- If dysrhythmia due to decreased potassium or magnesium is suspected, replace aggressively
- If no symptoms are noted after 6 hours, discontinue treatment
Dosing Modifications
Renal impairment
- CrCl <10 mL/min: Ineffective; do not use
- CrCl >10 mL/min: Dose adjustment not necessary
Pediatric dosage forms and strengths
tablet
- 15mg
- 25mg
- 50mg
- 100mg
Hypertension (Off-label)
0.3 mg/kg/day PO initially; may be increased to 2 mg/kg/day; not to exceed 50 mg/day
Geriatric dosage forms and strengths
Potential for electrolyte imbalance in elderly; monitor serum electrolytes
Diuresis
12.5-25 mg/day PO or 12.5-25 mg PO every other day; dosages >25 mg/day offer only minimal advantage
Hypertension
25-100 mg/day PO; usual range, 12.5-25 mg/day
Edema
50-100 mg/day PO or 100 mg PO every other day; not to exceed 200 mg/day
Heart Failure
12.5-25 mg/day PO; not to exceed 100 mg/day
Hygroton, Thalitone (chlorthalidone) adverse (side) effects
Common
Cardiovascular: Hypotension, vasculitis
Dermatologic: Photosensitivity, phototoxicity
Endocrine/metabolic: Electrolyte abnormalities, hyperglycemia, hyperuricemia
Gastrointestinal: Constipation, diarrhea, loss of appetite, nausea, vomiting
Musculoskeletal: Spasticity
Neurologic: Dizziness, headache, paresthesia
Ophthalmologic: Blurred vision, xanthopsia
Psychiatric: Restlessness
Reproductive: Impotence
Serious
Cardiovascular: Cardiac dysrhythmia (rare)
Dermatologic: Scaling eczema (rare), Stevens-Johnson syndrome (rare), toxic epidermal necrolysis (rare)
Gastrointestinal: Pancreatitis (rare)
Hematologic: Disorder of hematopoietic structure (rare)
Hepatic: Hepatotoxicity (rare)
Immunologic: Systemic lupus erythematosus (rare)
Respiratory: Pulmonary edema (rare)
Warnings
Contraindications
Documented hypersensitivity to chlorthalidone or sulfonamides
Anuria
Cautions
Use with caution in diabetes mellitus, fluid or electrolyte imbalance, hypercholesterolemia, hyperuricemia or gout, hypotension, systemic lupus erythematosus, liver disease, severe renal disease, advanced age, history of allergy or bronchial asthma
Avoid concurrent use with lithium (reduction of lithium dosage by 50% may be necessary)
May aggravate digitalis toxicity
Patients allergic to sulfa drugs may show cross-sensitivity
Risk of male sexual dysfunction
Photosensitization may occur
Electrolyte disturbances (eg, hypokalemia, hyponatremia, hypochloremic alkalosis) may occur
Pregnancy and lactation
Pregnancy category: B; D (expert analysis); possible hazards include fetal or neonatal jaundice, thrombocytopenia, and other adverse reactions that have occurred in adults
Lactation: Drug enters breast milk; not recommended (American Academy of Pediatrics states that it is "compatible with nursing")
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Hygroton, Thalitone (chlorthalidone)
Mechanism of action
Similar to thiazide diuretics; inhibits sodium and chloride reabsorption in cortical diluting segment of ascending loop of Henle, causing increased excretion of sodium, chloride, and water
Absorption
Bioavailability: 65%
Onset: 2-6 hr
Duration: 24-72 hr
Peak plasma time: 1.5-6 hr
Distribution
Protein bound: 75%
Metabolism
Metabolized in liver
Elimination
Half-life: Normal renal function, 40-60 hr; anuria, 81 hr
Dialyzable: No
Total body clearance: 53-145 mL/min
Excretion: Urine (50-65%), feces
