Home Drug Guide Ritonavir

Drug Guide

Generic Name

Ritonavir

Brand Names Norvir

Classification

Therapeutic: Antiretroviral agent, Protease inhibitor

Pharmacological: Viral protease inhibitor

FDA Approved Indications

  • Treatment of HIV-1 infection in combination with other antiretroviral agents

Mechanism of Action

Inhibits the HIV protease enzyme, preventing viral maturation and producing non-infectious viral particles.

Dosage and Administration

Adult: Typically 300 mg twice daily with food, in combination with other antiretrovirals.

Pediatric: Dosing varies; consult specific guidelines.

Geriatric: Adjust dose based on renal and hepatic function, caution due to comorbidities.

Renal Impairment: Use with caution; no specific dose adjustment, but renal function should be monitored.

Hepatic Impairment: Use with caution; dose adjustment may be necessary due to extensive hepatic metabolism.

Pharmacokinetics

Absorption: Well absorbed orally, food increases bioavailability.

Distribution: Widely distributed; crosses the blood-brain barrier.

Metabolism: Primarily metabolized in the liver via CYP3A4 and CYP2D6.

Excretion: Metabolites are excreted mainly in feces; minimal renal excretion.

Half Life: Approx. 3-5 hours; adjusted when given with other drugs.

Contraindications

  • Use caution in patients with hypersensitivity to ritonavir or other components.
  • Contraindicated with certain drugs that are CYP3A4 substrates, QT prolongation risk, or when combined with drugs that can cause torsades de pointes.

Precautions

  • Hepatic impairment, especially hepatitis B or C co-infection.
  • Use with caution in patients with significant cardiac disease or QT prolongation.
  • Pregnancy category B—discuss potential benefits and risks.

Adverse Reactions - Common

  • Gastrointestinal disturbances (nausea, vomiting, diarrhea) (Common)
  • Altered taste (dysgeusia) (Common)

Adverse Reactions - Serious

  • Hepatotoxicity (including hepatitis and hepatitis exacerbation) (Uncommon)
  • QT prolongation and Torsades de Pointes (Rare)
  • Drug hypersensitivity reactions (Rare)

Drug-Drug Interactions

  • Interactions with medications metabolized by CYP3A4 (e.g., certain statins, benzodiazepines, ergot derivatives)
  • Potential for increased levels of drugs like sildenafil, lidocaine, and certain antiarrhythmics.

Drug-Food Interactions

  • High-fat meals increase absorption; consistency recommended.

Drug-Herb Interactions

  • St. John’s Wort can significantly decrease ritonavir levels, reducing efficacy.

Nursing Implications

Assessment: Monitor liver function tests, lipid profile, and cardiac status (ECG) as needed.

Diagnoses:

  • Risk for hepatotoxicity
  • Risk for cardiac arrhythmias due to QT prolongation

Implementation: Administer with food, monitor for signs of hepatitis or cardiac issues, educate patient about interactions.

Evaluation: Check viral load response, monitor for adverse effects, ensure adherence.

Patient/Family Teaching

  • Take exactly as prescribed, with food.
  • Inform about potential side effects like gastrointestinal upset and altered taste.
  • Report signs of hepatotoxicity (jaundice, dark urine) or cardiac symptoms (chest pain, dizziness).
  • Avoid herbal supplements, especially St. John’s Wort.

Special Considerations

Black Box Warnings:

  • Serious drug interactions resulting in adverse outcomes such as hepatic failure or cardiac arrhythmias.
  • Potential for hepatotoxicity and increased bleeding in hemophilia patients.

Genetic Factors: Pharmacogenetic variations in CYP3A4 may influence drug levels.

Lab Test Interference: Can affect lipid panels, hepatic function tests.

Overdose Management

Signs/Symptoms: Nausea, vomiting, hypotension, dizziness, and possible hepatic injury.

Treatment: Supportive care; no specific antidote. Discontinue drug, monitor cardiac and hepatic function, provide symptomatic treatment.

Storage and Handling

Storage: Store at room temperature (15-30°C), protected from light and moisture.

Stability: Stable under recommended storage conditions for the duration specified in the label.

🛡️ 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.