Retrovir (zidovudine) is a nucleoside reverse transcriptase inhibitor (NRTI) indicated for the treatment of human immunodeficiency virus (HIV) infection. As one of the foundational agents in antiretroviral therapy (ART), it plays a critical role in suppressing viral replication, slowing disease progression, and improving immune function. This medication is typically used in combination with other antiretroviral agents as part of a comprehensive treatment strategy tailored to individual patient needs and resistance profiles.

Features

• Active ingredient: Zidovudine 300 mg
• Formulation: Film-coated tablets, oral syrup, and intravenous solution
• Mechanism: Inhibits reverse transcriptase, preventing viral DNA synthesis
• Bioavailability: Approximately 60-70% orally
• Half-life: 1-1.5 hours (intracellular half-life: 3-4 hours)
• Metabolism: Hepatic glucuronidation
• Excretion: Primarily renal (50-80% as metabolites)

Benefits

• Effectively reduces HIV viral load when used in combination therapy
• Helps restore and preserve CD4+ T-cell counts
• Demonstrates proven efficacy in reducing mother-to-child transmission
• May be used as part of post-exposure prophylaxis regimens
• Available in multiple formulations for flexible dosing
• Well-established safety profile with decades of clinical experience

Common use

Retrovir is primarily indicated for the treatment of HIV-1 infection in adults and children, always in combination with other antiretroviral agents. It is also approved for the prevention of maternal-fetal HIV transmission when administered during pregnancy, labor, and to the neonate. Additionally, it may be used as part of occupational post-exposure prophylaxis following potential HIV exposure. The medication is typically prescribed as part of initial ART regimens or as an alternative option based on resistance testing and patient-specific factors.

Dosage and direction

Adults: 300 mg twice daily or 200 mg three times daily
Children (aged 4 weeks to 18 years): 160 mg/m² body surface area twice daily (maximum 200 mg per dose)
Neonates (birth to 4 weeks): 2 mg/kg orally every 6 hours
IV administration: 1-2 mg/kg infused over 1 hour every 4 hours

Dosage adjustments are required for patients with impaired renal function (creatinine clearance <50 mL/min) or significant hepatic impairment. Tablets should be swallowed whole with water, with or without food. The oral syrup formulation should be measured precisely using the provided dosing syringe.

Precautions

• Monitor complete blood counts at baseline and every 4 weeks during therapy due to risk of hematologic toxicity
• Assess liver function regularly, particularly in patients with pre-existing liver disease
• Use with caution in patients with bone marrow suppression or risk factors for myopathy
• Consider vitamin B12 levels in patients with macrocytic anemia
• Monitor for lactic acidosis, particularly in obese patients and women
• Regular assessment of body fat distribution recommended for lipodystrophy monitoring
• Dental monitoring advised due to potential for oral pigmentation changes

Contraindications

• Hypersensitivity to zidovudine or any component of the formulation
• Life-threatening allergic reactions to any other NRTI medications
• Concomitant use with stavudine due to antagonistic effects
• Patients with significantly low neutrophil counts (<0.75 × 10⁹/L) or hemoglobin levels (<7.5 g/dL)
• Severe hepatic impairment without appropriate dosage adjustment

Possible side effect

Common (≥10%): Headache, nausea, vomiting, insomnia, asthenia
Less common (1-10%): Anemia, neutropenia, thrombocytopenia, myalgia, fever, rash, dyspepsia
Rare (<1%): Lactic acidosis, severe hepatomegaly with steatosis, myopathy, lipodystrophy, hyperpigmentation of nails and skin
Laboratory abnormalities: Elevated liver enzymes, macrocytosis, elevated amylase

Drug interaction

• Ganciclovir/valganciclovir: Increased risk of hematologic toxicity
• Ribavirin: Antagonistic antiviral effect; avoid concomitant use
• Probenecid: May increase zidovudine levels through reduced glucuronidation
• Phenytoin: May decrease phenytoin levels; monitor concentrations
• Methadone: May increase zidovudine levels by approximately 40%
• Other bone marrow suppressive agents: Additive hematologic toxicity risk
• Doxorubicin: Potential increased risk of hematologic toxicity

Missed dose

If a dose is missed, take it as soon as remembered unless it is nearly time for the next scheduled dose. Do not double the dose to make up for a missed dose. Maintain regular dosing schedule to ensure consistent antiviral suppression. If multiple doses are missed, contact healthcare provider for guidance on resuming therapy and potential need for additional monitoring.

Overdose

Symptoms may include nausea, vomiting, lethargy, and hematologic toxicity. There is no specific antidote for zidovudine overdose. Management includes supportive care with monitoring of hematologic parameters for at least six weeks. Hemodialysis may enhance elimination as zidovudine is moderately dialyzable. Consider hematologic support including transfusions if indicated based on laboratory findings.

Storage

Store at controlled room temperature (20-25°C/68-77°F). Keep in original container with tight closure. Protect from light and moisture. Oral syrup should be stored at 2-8°C (36-46°F) and used within 30 days of opening. Do not freeze. Keep out of reach of children and pets. Properly discard any unused medication after expiration date or when no longer needed.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Retrovir is a prescription medication that should only be used under the supervision of a qualified healthcare professional. Individual response to therapy may vary. Patients should discuss their complete medical history, including all current medications and health conditions, with their healthcare provider before starting treatment. Adherence to prescribed regimen and regular monitoring are essential for optimal outcomes.

Reviews

“Retrovir has been a cornerstone of HIV therapy for decades. While newer agents offer improved side effect profiles, zidovudine remains valuable in specific clinical scenarios, particularly in resource-limited settings and prevention of vertical transmission.” - Infectious Disease Specialist, 15 years experience

“Patient tolerance has improved with better supportive care, though we remain vigilant about monitoring hematologic parameters. The twice-daily formulation has significantly improved adherence compared to the historical TID dosing.” - HIV Clinical Pharmacist

“Despite the emergence of newer antiretrovirals, Retrovir maintains its place in therapy due to its well-characterized safety profile and extensive clinical experience. It continues to be particularly important in pediatric HIV management and prevention of mother-to-child transmission.” - Clinical Researcher, HIV Therapeutics