Home Drug Guide Lamivudine

Drug Guide

Generic Name

Lamivudine

Brand Names Epivir, Epivir-HBV

Classification

Therapeutic: Antiviral agent, nucleoside analogue

Pharmacological: Reverse transcriptase inhibitor

FDA Approved Indications

  • Chronic hepatitis B virus (HBV) infection in adults and children aged ≥3 months
  • HIV-1 infection in adults and pediatric patients

Mechanism of Action

Lamivudine inhibits viral DNA synthesis by mimicking cytidine and incorporating into viral DNA via reverse transcriptase, leading to chain termination.

Dosage and Administration

Adult: 100 mg once daily for HBV; 300 mg once daily or 150 mg twice daily for HIV

Pediatric: 0.5 mg/kg (up to 300 mg) once daily for HBV in children ≥3 months; 2 mg/kg (up to 300 mg) twice daily for HIV in children ≥3 months

Geriatric: Adjust dose based on renal function; no specific age adjustment but caution advised due to renal impairment

Renal Impairment: Reduce dose based on creatinine clearance; typically 25 mg daily if CrCl 15-29 mL/min, and 15 mg daily if CrCl <15 mL/min

Hepatic Impairment: No specific adjustment necessary for hepatic impairment

Pharmacokinetics

Absorption: Orally well absorbed

Distribution: Widely distributed into body tissues and fluids

Metabolism: Negligible metabolism; primarily excreted unchanged

Excretion: Renal excretion via glomerular filtration and active tubular secretion

Half Life: 5-7 hours

Contraindications

  • Hypersensitivity to lamivudine or any component

Precautions

  • Lactic acidosis and severe hepatomegaly with steatosis reported with nucleoside analogues; use with caution in patients with renal impairment; monitor renal function regularly

Adverse Reactions - Common

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

Adverse Reactions - Serious

  • Lactic acidosis (Rare)
  • Acute exacerbation of hepatitis B upon discontinuation (Rare)

Drug-Drug Interactions

  • Emtricitabine (may increase risk of lactic acidosis)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor renal function, serum lactate, and hepatic function

Diagnoses:

  • Risk for impaired renal function

Implementation: Administer as directed; monitor for signs of lactic acidosis or hepatomegaly

Evaluation: Assess viral load and liver function tests periodically to evaluate effectiveness

Patient/Family Teaching

  • Take medication exactly as prescribed
  • Report symptoms of lactic acidosis (mġus, muscle pain, difficulty breathing) or hepatomegaly
  • Maintain regular follow-up appointments

Special Considerations

Black Box Warnings:

  • Severe acute exacerbations of hepatitis B may occur when used for hepatitis B patients and discontinued

Genetic Factors: None specified

Lab Test Interference: May cause false-positive result for serum hepatitis B surface antigen (HBsAg)

Overdose Management

Signs/Symptoms: Nausea, vomiting, somnolence, dizziness, coma, and lactic acidosis

Treatment: Supportive care; hemodialysis may be considered if significant overdose occurs, especially if renal function is impaired

Storage and Handling

Storage: Store at room temperature 25°C (77°F); keep container tightly closed

Stability: Stable for up to 1 year 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.