Chlorthalidone

Chlorthalidone

Drug monograph · NCLEX study reference
Therapeutic class	Antihypertensive, diuretic
Pharmacologic class	Thiazide-like diuretic
Onset / peak / duration	Onset about 2 hours; peak 2 to 6 hours; duration 24 to 72 hours.
Half-life / level	Half-life 40 to 60 hours; no routine level.
Routes	PO (oral)
High-alert (ISMP)	No
Black box warning	None
Antidote / reversal	None; correct electrolytes.
Pregnancy / lactation	Use only if clearly needed.

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Chlorthalidone — Antihypertensive, diuretic; Thiazide-like diuretic.

Identification

• Therapeutic class: Antihypertensive, diuretic.
• Pharmacologic class: Thiazide-like diuretic.

Pharmacology

• Mechanism of action: Same distal tubule action as thiazides with a longer duration.
• Onset / peak / duration: Onset about 2 hours; peak 2 to 6 hours; duration 24 to 72 hours.
• Half-life / therapeutic level: Half-life 40 to 60 hours; no routine level.

Clinical use

• Indications: Hypertension, edema.
• Usual dose, route, frequency: 12.5 to 25 mg PO once daily.
• Maximum dose / adjustments: Max about 50 mg/day; greater potassium loss than hydrochlorothiazide.

Safety

• Contraindications: Anuria, sulfonamide hypersensitivity.
• Black box warning: None.
• Interactions: Same as hydrochlorothiazide; digoxin, lithium, NSAIDs.
• Pregnancy / lactation: Use only if clearly needed.
• High-alert: No.

Adverse effects

• Common side effects: Hypokalemia, hyponatremia, increased urination, dizziness.
• Serious effects to report: Severe electrolyte disturbance, dehydration.
• Antidote / reversal: None; correct electrolytes.

Nursing process

• Assessment before administration: Blood pressure, electrolytes, renal function.
• Interventions during therapy: Morning dosing; monitor potassium closely.
• Monitor: Electrolytes, blood pressure, glucose, uric acid.
• Evaluation / expected outcome: Sustained blood pressure reduction.

Patient teaching

• Patient teaching: Take in the morning; report cramps or weakness.
• Notify provider if: Muscle weakness, palpitations, severe dizziness.
• Administration tips: Morning dosing.