Home Drug Guide Phenindione

Drug Guide

Generic Name

Phenindione

Brand Names Hedulin

Classification

Therapeutic: Anticoagulant

Pharmacological: Vitamin K antagonist

FDA Approved Indications

  • Prevention and treatment of thromboembolic disorders, such as deep vein thrombosis, pulmonary embolism, and atrial fibrillation-related embolism

Mechanism of Action

Inhibits synthesis of vitamin K-dependent clotting factors II, VII, IX, and X, thereby impairing clot formation

Dosage and Administration

Adult: Typically 100-200 mg daily, divided into doses; dosage adjusted based on INR monitoring

Pediatric: Not commonly used; limited data available, consult specialist

Geriatric: Start with lower doses due to increased bleeding risk; monitor closely

Renal Impairment: Use with caution; dose adjustments may be necessary depending on renal function

Hepatic Impairment: Use with caution; hepatic function affects drug metabolism

Pharmacokinetics

Absorption: Well absorbed orally

Distribution: Widely distributed; crosses placental barrier

Metabolism: Metabolized in the liver by CYP enzymes

Excretion: Excreted primarily in urine

Half Life: Approximately 8-12 hours; varies among individuals

Contraindications

  • Known hypersensitivity to phenindione or other vitamin K antagonists
  • Active bleeding
  • Bleeding disorders

Precautions

  • Use with caution in patients with hepatic or renal impairment, bleeding tendencies, or recent surgery
  • Monitor INR regularly

Adverse Reactions - Common

  • Bleeding (Common)
  • Nausea (Less common)
  • Vomiting (Less common)

Adverse Reactions - Serious

  • Hemorrhage (Serious and requires immediate attention)
  • Decresed bone marrow function (Rare)

Drug-Drug Interactions

  • Other anticoagulants, antiplatelet agents, NSAIDs, CYP450 inhibitors or inducers

Drug-Food Interactions

  • Vitamin K-rich foods (e.g., green leafy vegetables) may reduce efficacy

Drug-Herb Interactions

  • Herbal supplements affecting coagulation (e.g., garlic, ginkgo)

Nursing Implications

Assessment: Monitor bleeding, INR, hepatic and renal function

Diagnoses:

  • Risk for bleeding
  • Impaired tissue perfusion

Implementation: Administer as prescribed, educate patient on bleeding precautions

Evaluation: Regularly evaluate INR levels and adjust dose accordingly

Patient/Family Teaching

  • Take medication exactly as prescribed
  • Report signs of bleeding (e.g., unusual bruising, blood in stool or urine)
  • Maintain consistent intake of vitamin K-rich foods
  • Avoid alcohol and other medications that increase bleeding risk
  • Schedule regular INR monitoring appointments

Special Considerations

Black Box Warnings:

  • Significant bleeding risk; requires careful monitoring

Genetic Factors: Genetic polymorphisms in CYP2C9 can affect metabolism and dosing

Lab Test Interference: May interfere with certain coagulation assays

Overdose Management

Signs/Symptoms: Excessive bleeding, hematuria, gastrointestinal bleeding

Treatment: Discontinue drug, provide supportive care, administer vitamin K, consider fresh frozen plasma or prothrombin complex concentrates in severe cases

Storage and Handling

Storage: Store at room temperature, away from moisture and sunlight

Stability: Stable for the duration specified on the package; verify expiration date

🛡️ 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.