Medical term:

Hygroton


chlorthalidone

Apo-Chlorthalidone (CA), Hygroton (UK), Novo-Thalidone (CA), Thalitone, Uridon (CA)

Pharmacologic class: Thiazide-like diuretic

Therapeutic class: Diuretic, antihypertensive

Pregnancy risk category B

Action

Unclear. Enhances excretion of sodium, chloride, and water by interfering with transport of sodium ions across renal tubular epithelium. Also may dilate arterioles.

Availability

Tablets: 15 mg, 25 mg, 50 mg, 100 mg

Indications and dosages

➣ Edema associated with heart failure, renal dysfunction, cirrhosis, corticosteroid therapy, and estrogen therapy

Adults: 50 to 100 mg/day (30 to 60 mg Thalitone) P.O. or 100 mg every other day (60 mg Thalitone) P.O., up to 200 mg/day (120 mg Thalitone) P.O.

➣ Management of mild to moderate hypertension

Adults: 25 mg/day (15 mg Thalitone) P.O. Based on patient response, may increase to 50 mg/day (30 to 50 mg Thalitone) P.O., then up to 100 mg/day (except Thalitone) P.O.

Contraindications

• Hypersensitivity to drug, other thiazides, sulfonamides, or tartrazine

• Renal decompensation

Precautions

Use cautiously in:

• renal or severe hepatic disease, abnormal glucose tolerance, gout, systemic lupus erythematosus, hyperparathyroidism, bipolar disorder

• elderly patients

• pregnant or breastfeeding patients.

Administration

• Know that dosages above 25 mg/day are likely to increase potassium excretion without further increasing sodium excretion or reducing blood pressure.

Adverse reactions

CNS: dizziness, vertigo, drowsiness, lethargy, confusion, headache, insomnia, nervousness, paresthesia, asterixis, nystagmus, encephalopathy

CV: hypotension, ECG changes, chest pain, arrhythmias, thrombophlebitis

GI: nausea, vomiting, cramping, anorexia, pancreatitis

GU: polyuria, nocturia, erectile dysfunction, loss of libido

Hematologic: blood dyscrasias

Metabolic: gout attack, dehydration, hyperglycemia, hypokalemia, hypocalcemia, hypomagnesemia, hyponatremia, hypophosphatemia, hyperuricemia, hyperlipidemia,

hypochloremic alkalosis

Musculoskeletal: muscle cramps, muscle spasms

Skin: flushing, photosensitivity, hives, rash, exfoliative dermatitis, toxic epidermal necrolysis

Other: fever, weight loss, hypersensitivity reactions

Interactions

Drug-drug. Allopurinol: increased risk of hypersensitivity reaction

Amphotericin B, corticosteroids, mezlocillin, piperacillin, ticarcillin: additive hypokalemia

Antihypertensives, barbiturates, nitrates, opiates: increased hypotension

Cholestyramine, colestipol: decreased chlorthalidone blood level

Digoxin: increased risk of hypokalemia

Lithium: increased risk of lithium toxicity

Nonsteroidal anti-inflammatory drugs: decreased diuretic effect

Drug-diagnostic tests. Bilirubin, calcium, creatinine, uric acid: increased levels

Glucose (in diabetic patients): increased blood and urine levels

Magnesium, potassium, protein-bound iodine, sodium, urine calcium: decreased levels

Drug-herbs. Ginkgo: decreased antihypertensive effects

Licorice, stimulant laxative herbs (aloe, cascara sagrada, senna): increased risk of potassium depletion

Drug-behaviors. Acute alcohol ingestion: additive hypotension

Sun exposure: increased risk of photosensitivity

Patient monitoring

• Closely monitor patient with renal insufficiency.

• Assess for signs and symptoms of hematologic disorders.

• Monitor CBC with white cell differential and serum uric acid and electrolyte levels.

• Assess for signs and symptoms of hypersensitivity reactions, especially dermatitis.

• Watch for fluid and electrolyte imbalances.

Patient teaching

• Instruct patient to consume a low-sodium diet containing plenty of potassium-rich foods and beverages (such as bananas, green leafy vegetables, and citrus juice).

• Caution patient to avoid driving and other hazardous activities until he knows whether drug makes him dizzy or affects concentration and alertness.

• Tell patient with diabetes to check urine or blood glucose level frequently.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved

chlorthalidone

(klor-thal-i-doan) ,

Hygroton

(trade name),

Thalitone

(trade name),

Uridon

(trade name)

Classification

Therapeutic: antihypertensives
Pharmacologic: thiazide diuretics
Pregnancy Category: B

Indications

Management of mild to moderate hypertension.Treatment of edema associated with:
  • HF,
  • Renal dysfunction,
  • Cirrhosis,
  • Glucocorticoid therapy,
  • Estrogen therapy.

Action

Increases excretion of sodium and water by inhibiting sodium reabsorption in the distal tubule.
Promotes excretion of chloride, potassium, magnesium, and bicarbonate.
May produce arteriolar dilation.

Therapeutic effects

Lowering of BP in hypertensive patients and diuresis with mobilization of edema.

Pharmacokinetics

Absorption: Rapidly absorbed after administration.
Distribution: Distributed into extracellular space; crosses the placenta and enters breast milk.
Metabolism and Excretion: Excreted mainly unchanged by the kidneys.
Half-life: 35–50 hr.

Time/action profile (diuretic effect)

ROUTEONSETPEAKDURATION
PO2 hr2 hr48–72 hr

Contraindications/Precautions

Contraindicated in: Hypersensitivity (cross-sensitivity with other thiazides or sulfonamides may exist); Some products contain tartrazine and should be avoided in patients with known intolerance; Anuria; Lactation: Lactation.
Use Cautiously in: Renal or hepatic impairment; Obstetric: May cause jaundice or thrombocytopenia in newborn.

Adverse Reactions/Side Effects

Central nervous system

  • dizziness
  • drowsiness
  • lethargy
  • weakness

Cardiovascular

  • hypotension

Gastrointestinal

  • anorexia
  • cramping
  • hepatitis
  • nausea
  • vomiting

Dermatologic

  • photosensitivity
  • rash

Endocrinologic

  • hyperglycemia

Fluid and Electrolyte

  • hypokalemia (most frequent)
  • dehydration
  • hypercalcemia
  • hypochloremic alkalosis
  • hypomagnesemia
  • hyponatremia
  • hypophosphatemia
  • hypovolemia

Hematologic

  • blood dyscrasias

Metabolic

  • hyperuricemia
  • hypercholesterolemia

Musculoskeletal

  • muscle cramps

Miscellaneous

  • pancreatitis

Interactions

Drug-Drug interaction

Additive hypotension with other antihypertensive agents, acute ingestion of alcohol ornitrates.Additive hypokalemia with corticosteroids, amphotericin B, piperacillin, or ticarcillin.↓ the excretion of lithium.Cholestyramine or colestipol ↓ absorption.Hypokalemia ↑ risk of digoxin toxicity.NSAIDs may ↓ effectiveness.

Route/Dosage

When used as a diuretic in adults, generally given daily, but may be given every other day or 2–3 days/week
Oral (Adults) 12.5–100 mg once daily (doses above 25 mg are associated with greater likelihood of electrolyte abnormalities).

Availability (generic available)

Tablets: 15 mg, 25 mg, 50 mg
In combination with: atenolol (Tenoretic), azilsartan (Edarbyclor), and clonidine (Clorpres). See combination drugs.

Nursing implications

Nursing assessment

  • Monitor BP, intake, output, and daily weight and assess feet, legs, and sacral area for edema daily.
    • Assess patient, especially if taking digitalis glycosides, for anorexia, nausea, vomiting, muscle cramps, paresthesia, and confusion. Notify physician or other health care professional if these signs of electrolyte imbalance occur. Patients taking digitalis glycosides are at risk of digitalis toxicity as a result of the potassium-depleting effect of the diuretic.
    • Assess patient for allergy to sulfonamides.
  • Hypertension: Monitor BP before and periodically throughout therapy.
    • Monitor frequency of prescription refills to determine compliance.
  • Lab Test Considerations: Monitor electrolytes (especially potassium), blood glucose, BUN, serum creatinine, and uric acid levels before and periodically throughout therapy.
    • May cause ↑ in serum and urine glucose in diabetic patients.
    • May cause ↑ in serum bilirubin, calcium, creatinine, and uric acid, and ↓ in serum magnesium, potassium, sodium, and urinary calcium concentrations.
    • May cause ↑ serum cholesterol, low-density lipoprotein, and triglyceride concentrations.

Potential Nursing Diagnoses

Excess fluid volume (Indications)
Risk for deficient fluid volume (Side Effects)

Implementation

  • Administer in the morning to prevent disruption of sleep cycle for urination.
    • Intermittent dose schedule may be used for continued control of edema.
  • Oral: May give with food or milk to minimize GI irritation. Tablets may be crushed and mixed with fluid to facilitate swallowing.

Patient/Family Teaching

  • Instruct patient to take this medication at the same time each day. If a dose is missed, take as soon as remembered but not just before next dose is due. Do not double doses.
    • Instruct patient to monitor weight biweekly and notify health care professional of significant changes.
    • Caution patient to change positions slowly to minimize orthostatic hypotension. This may be potentiated by alcohol.
    • Advise patient to use sunscreen and protective clothing to prevent photosensitivity reactions.
    • Instruct patient to discuss dietary potassium requirements with health care professional (see ).
    • Instruct patient to notify health care professional of medication regimen before treatment or surgery.
    • Advise patient to report muscle weakness, cramps, nausea, vomiting, diarrhea, or dizziness to health care professional.
    • Emphasize the importance of routine follow-up exams.
  • Hypertension: Advise patients to continue taking the medication even if feeling better. Medication controls but does not cure hypertension.
    • Encourage patient to comply with additional interventions for hypertension (weight reduction, low-sodium diet, regular exercise, smoking cessation, moderation of alcohol consumption, and stress management).
    • Instruct patient and family in correct technique for monitoring weekly BP.
    • Advise patient to consult health care professional before taking OTC medication, especially cough or cold preparations, concurrently with this therapy.

Evaluation/Desired Outcomes

  • Decrease in BP.
    • Decrease in edema.
Drug Guide, © 2015 Farlex and Partners

Hygroton

A brand name for CHLORTHALIDONE.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

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