Home Drug Guide Valacyclovir Hydrochloride

Drug Guide

Generic Name

Valacyclovir Hydrochloride

Brand Names Valtrex

Classification

Therapeutic: Antiviral

Pharmacological: Nucleoside analogue

FDA Approved Indications

  • Genital herpes simplex virus (HSV) infections
  • Herpes zoster (shingles)
  • Varicella (chickenpox)

Mechanism of Action

Valacyclovir is a prodrug that is rapidly converted to acyclovir, which inhibits viral DNA synthesis by acting as a substrate for viral DNA polymerase, thereby preventing viral replication.

Dosage and Administration

Adult: Dosage varies by condition; typically 1 g twice daily for herpes zoster or recurrent genital herpes; 1 g once daily for varicella in immunocompromised patients.

Pediatric: Not approved for children under 18; consult specific guidelines for age-specific dosing.

Geriatric: Adjust dose based on renal function; no specific age-related adjustments otherwise.

Renal Impairment: Reduce dose or increase dosing interval based on creatinine clearance.

Hepatic Impairment: No specific adjustment recommended.

Pharmacokinetics

Absorption: Rapidly absorbed from the gastrointestinal tract (~55% bioavailability).

Distribution: Widely distributed in body tissues; crosses blood-brain barrier.

Metabolism: Converted to active acyclovir in the intestinal wall and liver.

Excretion: Primarily excreted unchanged in urine.

Half Life: Approximately 2.5 to 3.3 hours in patients with normal renal function.

Contraindications

  • Hypersensitivity to valacyclovir, acyclovir, or any component of the formulation.

Precautions

  • Renal impairment: adjust dose accordingly.
  • Immunocompromised patients: monitor for signs of secondary infection.
  • Pregnancy and lactation: use only if clearly needed; benefits outweigh risks.

Adverse Reactions - Common

  • Headache (Common)
  • Nausea (Common)
  • Vomiting (Common)
  • Abdominal pain (Common)

Adverse Reactions - Serious

  • Nephrotoxicity (Rare)
  • Neurotoxicity (confusion, hallucinations, tremors) (Rare)
  • Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) (Rare)

Drug-Drug Interactions

  • Probenecid: may increase acyclovir levels
  • NSAIDs: increased risk of renal impairment

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor renal function, hydration status, and neurological status during therapy.

Diagnoses:

  • Risk for impaired renal function
  • Risk for secondary infections

Implementation: Administer as prescribed; ensure adequate hydration; monitor for adverse effects.

Evaluation: Assess for resolution of symptoms, monitor renal function, and adverse reactions.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Remain well-hydrated during therapy.
  • Report any signs of allergic reactions, neurotoxicity, or unusual symptoms immediately.
  • Use caution if operating machinery until responses are known.

Special Considerations

Black Box Warnings:

  • Nephrotoxicity and neurotoxicity, especially in patients with renal impairment or dehydration.

Genetic Factors: Not specifically documented.

Lab Test Interference: May increase serum creatinine levels; interpret accordingly.

Overdose Management

Signs/Symptoms: Nausea, vomiting, hallucinations, seizure, coma.

Treatment: Supportive care; consider hemodialysis in severe cases; ensure adequate hydration.

Storage and Handling

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

Stability: Stable through the expiration date 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.