Ribavirin disposition in high-risk patients for acquired immunodeficiency syndrome

Area of Science:

• Pharmacology
• Antiviral Drug Research
• Clinical Pharmacokinetics

Background:

• Ribavirin exhibits broad-spectrum antiviral activity in vitro, including against human immunodeficiency virus (HIV).
• Understanding the pharmacokinetic profile of ribavirin is crucial for optimizing its therapeutic use.

Purpose of the Study:

• To determine the pharmacokinetic parameters of ribavirin following oral and intravenous administration.
• To assess the linearity of ribavirin kinetics and potential for drug accumulation.

Main Methods:

• A pharmacokinetic study involving 17 HIV-positive men with lymphadenopathy.
• Administration of single oral or intravenous doses of ribavirin (600, 1200, or 2400 mg).
• Analysis of plasma ribavirin concentration-time profiles using a three-compartment open model.

Main Results:

• Ribavirin exhibited linear kinetics across the studied dose range.
• Mean oral bioavailability was 45% with an absorption half-life of 0.5 hours.
• Significant accumulation of ribavirin within red blood cells was observed, with renal excretion accounting for approximately one-third of elimination.

Conclusions:

• Ribavirin demonstrates incomplete absorption from the gastrointestinal tract.
• Repetitive dosing at 6- to 8-hour intervals may lead to greater than threefold drug accumulation.
• The findings suggest potential for dose adjustment or interval modification to optimize ribavirin therapy.