Home Drug Guide Tenofovir Disoproxil Fumarate

Drug Guide

Generic Name

Tenofovir Disoproxil Fumarate

Brand Names Viread

Classification

Therapeutic: Antiretroviral agent, Nucleoside reverse transcriptase inhibitor (NRTI)

Pharmacological: Nucleoside analog reverse transcriptase inhibitor

FDA Approved Indications

  • HIV-1 infection in adults, adolescents, and children aged 2 years and older
  • Chronic hepatitis B virus (HBV) infection in adults and pediatric patients aged 12 years and older

Mechanism of Action

Tenofovir disoproxil fumarate is converted in the body to tenofovir, an active metabolite that inhibits HIV-1 reverse transcriptase and HBV DNA polymerase by competing with natural substrates, leading to chain termination during viral DNA synthesis.

Dosage and Administration

Adult: 300 mg once daily, with or without food

Pediatric: Typically 8 mg/kg (maximum 300 mg) once daily, with or without food for children ≥2 years old

Geriatric: No specific dose adjustment; caution recommended due to potential renal impairment

Renal Impairment: Dose adjustment required; see prescribing information

Hepatic Impairment: Use with caution; no specific dose adjustment is usually necessary

Pharmacokinetics

Absorption: Rapidly absorbed with peak plasma concentrations in approximately 1 hour

Distribution: Widely distributed; minimal protein binding

Metabolism: Not significantly metabolized; active as the parent compound

Excretion: Primarily eliminated unchanged via the kidneys through glomerular filtration and active tubular secretion

Half Life: Approximately 12-18 hours

Contraindications

  • Hypersensitivity to tenofovir or any component of the formulation

Precautions

  • Renal impairment, hepatitis B co-infection, lactic acidosis risk, osteoporosis, concomitant use of nephrotoxic drugs, monitoring of renal function recommended

Adverse Reactions - Common

  • Nausea (Common)
  • Upper respiratory tract infections (Common)
  • Dizziness (Common)

Adverse Reactions - Serious

  • Lactic acidosis and severe hepatomegaly with steatosis (Rare)
  • Fanconi syndrome, renal proximal tubulopathy (Rare)
  • Bone mineral density loss (Rare)

Drug-Drug Interactions

  • Adefovir, cidofovir, concomitant nephrotoxic agents, zidovudine, didanosine

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor renal function (serum creatinine, eGFR), bone mineral density, and HIV viral load.

Diagnoses:

  • Risk for renal impairment
  • Risk for osteoporosis

Implementation: Administer once daily, counsel on adherence, monitor labs regularly, assess for symptoms of renal or liver issues.

Evaluation: Effective viral suppression, stable renal function, and no adverse effects.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report any signs of kidney problems (e.g., decreased urine output, swelling).
  • Maintain adequate hydration.
  • Avoid concurrent nephrotoxic drugs unless directed by the healthcare provider.

Special Considerations

Black Box Warnings:

  • Lactic acidosis and severe hepatomegaly with steatosis

Genetic Factors: Genetic variations may influence drug levels and toxicity

Lab Test Interference: Potential to cause false-positive urine glucose tests

Overdose Management

Signs/Symptoms: Nausea, vomiting, renal failure, lactic acidosis

Treatment: Supportive care, ensure adequate hydration, in case of significant overdose, consider hemodialysis to remove the drug.

Storage and Handling

Storage: Store at room temperature, 20-25°C (68-77°F), away from moisture and light.

Stability: Stable for the shelf life indicated by the manufacturer.

🛡️ 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.