Home Drug Guide Lamivudine and Zidovudine

Drug Guide

Generic Name

Lamivudine and Zidovudine

Brand Names Combivir, Lamivudine and Zidovudine

Classification

Therapeutic: Antiretroviral Agent (HIV) - Nucleoside Reverse Transcriptase Inhibitors (NRTIs)

Pharmacological: Nucleoside analog Reverse Transcriptase Inhibitors

FDA Approved Indications

  • HIV-1 infection in combination therapy

Mechanism of Action

Lamivudine and Zidovudine are nucleoside analog reverse transcriptase inhibitors that interfere with HIV viral replication by incorporating into viral DNA and terminating DNA chain elongation.

Dosage and Administration

Adult: Typically, 1 tablet twice daily, as per prescribing information; adjust based on clinical response.

Pediatric: Dose based on weight and age; consult specific pediatric dosing guidelines.

Geriatric: Start at lower end of dosing range due to potential renal impairment.

Renal Impairment: Adjust dose based on renal function; monitor serum creatinine and estimated glomerular filtration rate (eGFR).

Hepatic Impairment: No specific adjustment recommended for mild to moderate impairment; caution in severe impairment.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Wide distribution including into cerebrospinal fluid.

Metabolism: Not extensively metabolized; minimal hepatic metabolism.

Excretion: Primarily renal excretion via glomerular filtration and active tubular secretion.

Half Life: Lamivudine: ~5-7 hours; Zidovudine: ~1-2 hours.

Contraindications

  • Hypersensitivity to any component.
  • Lactic acidosis and hepatomegaly with steatosis risk in certain populations.

Precautions

  • Use with caution in hepatic impairment; monitor for mitochondrial toxicity; renal function monitoring needed; consider resistance patterns.

Adverse Reactions - Common

  • Headache (Common)
  • Nausea (Common)
  • Fatigue (Common)

Adverse Reactions - Serious

  • Myelosuppression (anemia, neutropenia) (Less common)
  • Lactic acidosis (Rare)
  • Hepatic steatosis and hepatotoxicity (Rare)

Drug-Drug Interactions

  • Rifampin (may reduce efficacy)
  • Other hepatotoxic drugs

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Baseline and periodic liver function tests, renal function, complete blood count.

Diagnoses:

  • Risk for infection
  • Risk for ineffective tissue perfusion related to myelosuppression.

Implementation: Administer with or without food; monitor lab values regularly; counsel patient on adherence and side effects.

Evaluation: Assess viral load, CD4 count, and tolerance of therapy.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report symptoms of liver problems or unusual bleeding.
  • Maintain regular lab appointments.
  • Use contraception to prevent pregnancy while on therapy.

Special Considerations

Black Box Warnings:

  • Lactic acidosis and severe hepatomegaly with steatosis.

Genetic Factors: Consider testing for hepatitis B infection, as withdrawal may lead to flare-up.

Lab Test Interference: Can cause increases in serum transaminases.

Overdose Management

Signs/Symptoms: Nausea, vomiting, pancreatitis, severe metabolic acidosis.

Treatment: Supportive care; no specific antidote. Dialysis may be considered in renal failure.

Storage and Handling

Storage: Store at room temperature, 20-25°C (68-77°F).

Stability: Stable under recommended storage conditions until 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.