Home Drug Guide Atenolol and Chlorthalidone

Drug Guide

Generic Name

Atenolol and Chlorthalidone

Brand Names Tenoretic 50, Tenoretic 100, Atenolol and Chlorthalidone

Classification

Therapeutic: Antihypertensive

Pharmacological: Beta-adrenergic blocker and Thiazide-like diuretic

FDA Approved Indications

  • Hypertension
  • Angina pectoris

Mechanism of Action

Atenolol blocks beta-1 adrenergic receptors, reducing heart rate and cardiac output; Chlorthalidone inhibits sodium reabsorption in the distal tubules, promoting diuresis — together lowering blood pressure.

Dosage and Administration

Adult: Typically 50 mg once daily, may be increased to 100 mg. Chlorthalidone 12.5-25 mg once daily.

Pediatric: Not approved for pediatric use.

Geriatric: Start at lower doses due to increased sensitivity and comorbidities.

Renal Impairment: Use with caution, dosage adjustments may be necessary.

Hepatic Impairment: Use with caution; dosage adjustments may be needed.

Pharmacokinetics

Absorption: Well-absorbed orally.

Distribution: Atenolol is approximately 50% protein-bound; Chlorthalidone is minimally protein-bound.

Metabolism: Atenolol undergoes minimal metabolism; Chlorthalidone undergoes hepatic metabolism.

Excretion: Primarily renal excretion.

Half Life: Atenolol approximately 6-7 hours; Chlorthalidone approximately 40-50 hours.

Contraindications

  • Second- or third-degree AV block
  • Sinus bradycardia
  • Heart failure (unstable)
  • Hypersensitivity to ingredients

Precautions

  • Asthma or bronchospastic conditions
  • Diabetes mellitus (may mask hypoglycemia)
  • Electrolyte imbalances

Adverse Reactions - Common

  • Dizziness (Common)
  • Fatigue (Common)
  • Hypotension (Common)
  • Electrolyte disturbances (e.g., hypokalemia) (Common)

Adverse Reactions - Serious

  • Bradycardia (Serious)
  • Heart failure (worsening) (Serious)
  • Electrolyte imbalances leading to arrhythmias (Serious)
  • Severe hypotension or shock (Serious)

Drug-Drug Interactions

  • Other antihypertensives
  • Calcium channel blockers
  • NSAIDs increasing blood pressure effects

Drug-Food Interactions

  • Alcohol may enhance hypotensive effects

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood pressure, heart rate, respiratory status, electrolyte levels.

Diagnoses:

  • Risk for falls related to hypotension
  • Impaired cardiac output

Implementation: Administer with food to decrease GI upset, monitor vital signs closely, especially after initiation or dosage changes.

Evaluation: Assess blood pressure and heart rate regularly to determine efficacy and safety.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Notify provider if experiencing dizziness, fainting, or irregular heartbeat.
  • Avoid sudden discontinuation to prevent rebound hypertension.
  • Limit alcohol intake and monitor salt intake.

Special Considerations

Black Box Warnings:

  • Use with caution in certain patients due to risk of worsening heart failure or bradycardia.

Genetic Factors: Pharmacogenomic variations may affect beta-blocker response.

Lab Test Interference: May alter glucose and lipid levels.

Overdose Management

Signs/Symptoms: Severe bradycardia, hypotension, bronchospasm, hypoglycemia, seizures.

Treatment: Supportive care, activated charcoal if recent ingestion, atropine for bradycardia, vasopressors for hypotension, dialysis in severe cases.

Storage and Handling

Storage: Store at room temperature away from moisture and heat.

Stability: Stable under recommended conditions for specified shelf life.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.