Home Drug Guide Captopril

Drug Guide

Generic Name

Captopril

Brand Names Capoten

Classification

Therapeutic: Antihypertensive, ACE inhibitor

Pharmacological: Angiotensin-Converting Enzyme (ACE) Inhibitor

FDA Approved Indications

  • Hypertension
  • Heart failure
  • Diabetic nephropathy

Mechanism of Action

Captopril inhibits angiotensin-converting enzyme, reducing the formation of angiotensin II, leading to vasodilation, decreased blood pressure, and reduced aldosterone secretion.

Dosage and Administration

Adult: Typically 25 mg two to three times daily, titrated based on response.

Pediatric: Dosage varies; usually initiated at 0.12-0.5 mg/kg/dose two times daily and adjusted as needed.

Geriatric: Start at lower doses due to increased sensitivity, monitor renal function and electrolytes.

Renal Impairment: Dose adjustment needed; typically reduce dose or increase dosing interval.

Hepatic Impairment: Use with caution; no specific dose adjustments but monitor closely.

Pharmacokinetics

Absorption: Well absorbed orally, with about 75% bioavailability.

Distribution: Wide distribution, crosses the placenta.

Metabolism: Minimal hepatic metabolism; some conjugation occurs.

Excretion: Primarily excreted unchanged in urine.

Half Life: 2 to 4 hours.

Contraindications

  • History of angioedema related to previous ACE inhibitor therapy.
  • Bilateral renal artery stenosis.
  • Hypersensitivity to captopril or other ACE inhibitors.

Precautions

  • Pregnancy (category D), especially in second and third trimesters.
  • Renal impairment, hyperkalemia, hypotension, collagen vascular disease, especially systemic lupus erythematosus.

Adverse Reactions - Common

  • Cough (Common)
  • Elevated blood potassium (hyperkalemia) (Common)
  • Hypotension (Common)

Adverse Reactions - Serious

  • Angioedema (Rare but serious)
  • Neutropenia/agranulocytosis (Rare)
  • Renal failure (Rare)

Drug-Drug Interactions

  • Diuretics, especially potassium-sparing (risk of hyperkalemia)
  • Other antihypertensives (additive effect)
  • Potassium supplements, potassium-containing salt substitutes
  • NSAIDs (reduce antihypertensive effect and risk of renal impairment)

Drug-Food Interactions

  • Potassium-rich foods (risk of hyperkalemia)

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood pressure, renal function, electrolytes, and for signs of angioedema.

Diagnoses:

  • Risk for injury related to hypotension or angioedema.
  • Electrolyte imbalance.

Implementation: Administer on an empty stomach 1 hour before meals or 2 hours after. Monitor BP and labs regularly.

Evaluation: Assess BP response, renal function, and electrolyte levels periodically.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report signs of angioedema (swelling of face, lips, tongue, or throat).
  • Avoid potassium-rich foods and supplements unless directed.
  • Monitor blood pressure regularly.

Special Considerations

Black Box Warnings:

  • Potential for fetal injury and death when used during pregnancy.
  • Angioedema risk.

Genetic Factors: Genetic predisposition may influence drug metabolism and adverse effects.

Lab Test Interference: May increase serum potassium and serum creatinine; monitor accordingly.

Overdose Management

Signs/Symptoms: Severe hypotension, dizziness, fainting, electrolyte disturbances.

Treatment: Discontinue drug, restore blood pressure with IV fluids, and administer vasopressors if necessary. Dialysis may be required in severe cases.

Storage and Handling

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

Stability: Stable for 2-3 years when stored properly.

🛡️ 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.