Home Drug Guide Hydrochlorothiazide; Irbesartan

Drug Guide

Generic Name

Hydrochlorothiazide; Irbesartan

Brand Names Avalide, Irbesartan And Hydrochlorothiazide, Irbesartan Hydrochlorothiazide

Classification

Therapeutic: Antihypertensive, Diuretic

Pharmacological: Angiotensin II Receptor Blocker (Irbesartan) combined with Thiazide Diuretic (Hydrochlorothiazide)

FDA Approved Indications

  • Treatment of hypertension to reduce blood pressure

Mechanism of Action

Irbesartan blocks angiotensin II receptors, leading to vasodilation and decreased blood pressure. Hydrochlorothiazide inhibits sodium reabsorption in the distal tubules of the kidney, promoting diuresis and reducing blood volume, which lowers blood pressure.

Dosage and Administration

Adult: Typically 150 mg of irbesartan with 12.5 mg of hydrochlorothiazide once daily; dosage may be adjusted based on response.

Pediatric: Not approved for pediatric use.

Geriatric: Adjust dose based on renal function; start at lower end of dosing range.

Renal Impairment: Use with caution; dose adjustment may be necessary.

Hepatic Impairment: Use with caution; no specific dose adjustment approved.

Pharmacokinetics

Absorption: Irbesartan is well absorbed; hydrochlorothiazide absorption is incomplete but consistent.

Distribution: Irbesartan is approximately 95% protein-bound; hydrochlorothiazide is moderately protein-bound.

Metabolism: Irbesartan undergoes minimal metabolism; hydrochlorothiazide is not extensively metabolized.

Excretion: Irbesartan excreted primarily via feces and urine; hydrochlorothiazide mainly excreted unchanged in urine.

Half Life: Irbesartan: approximately 11-15 hours; hydrochlorothiazide: about 6-15 hours.

Contraindications

  • Hypersensitivity to irbesartan, hydrochlorothiazide, or sulfonamides.
  • Anuria.

Precautions

  • Pregnancy (category D), especially after the first trimester.
  • History of angioedema related to previous ACE inhibitor or ARB therapy.
  • Electrolyte disturbances, renal impairment, hepatic impairment.

Adverse Reactions - Common

  • Dizziness (common)
  • Hypotension (common)
  • Electrolyte imbalance (e.g., hypokalemia, hyponatremia) (common)

Adverse Reactions - Serious

  • Angioedema (rare)
  • Renal failure (rare)
  • Hypersensitivity reactions (rare)

Drug-Drug Interactions

  • Other antihypertensives, especially diuretics and ACE inhibitors.
  • Lithium (increased risk of toxicity).
  • NSAIDs (may reduce antihypertensive effect).

Drug-Food Interactions

  • Excessive potassium intake (risk of hyperkalemia).

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood pressure, renal function, and electrolyte levels regularly.

Diagnoses:

  • Risk for electrolyte imbalance
  • Ineffective tissue perfusion related to hypotension

Implementation: Administer with food to reduce gastrointestinal upset; monitor for signs of hypotension, electrolyte disturbances.

Evaluation: Assess blood pressure and laboratory values periodically to evaluate effectiveness and safety.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report signs of allergic reactions, angioedema, or severe dizziness.
  • Be cautious about potassium intake.
  • Avoid pregnancy and use reliable contraception.

Special Considerations

Black Box Warnings:

  • Pregnancy category D; fetal toxicity.

Genetic Factors: None specified.

Lab Test Interference: Can cause alterations in serum electrolyte and renal function tests.

Overdose Management

Signs/Symptoms: Severe hypotension, electrolyte disturbances, dehydration.

Treatment: Stop medication, provide supportive care, rehydrate as needed, monitor electrolytes and renal function.

Storage and Handling

Storage: Store at room temperature, 15-30°C.

Stability: Stable under recommended storage conditions.

🛡️ 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.