Acyclovir
Guanosine analog antiviral selectively phosphorylated by viral thymidine kinase to its active triphosphate, inhibiting herpesvirus DNA polymerase. Poor oral bioavailability (~20%) necessitates frequent dosing: 200-800 mg up to 5 times daily. Mainstay therapy for HSV and VZV. Renal elimination; adjust in CKD to avoid crystal nephropathy.
Projected serum levels — 400 mg, custom (shown daily)
Maintenance schedule: 400 mg custom (shown daily) (oral).
Modeled steady state after ~1 days: peak ≈ 47.3 mg, trough ≈ 0.25 mg body load. Population-based estimate over 15 days for a 400 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Antibiotic
- Route modeled
- Oral
- Model confidence
- inferred
- Half-life
- 2.5 h
- Common dose
- 400 mg
- Suggested maximum
- 4k mg/day
- Reference dose range
- 200–4k mg (single dose)
- Suggested cadence
- custom (shown daily)
- Validated against
- 200 mg oral — Cmax 0.56 mg/L at 1.5 h
Research behind this entry
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Pharmacokinetics and tolerance of acyclovir, a new anti-herpesvirus agent, in humans
Foundational PK study establishing acyclovir's ~15-20% oral bioavailability, 2.5-hour terminal half-life, and predominantly renal elimination via active tubular secretion.
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Treatment of recurrent genital herpes simplex infections with oral acyclovir. A controlled trial
Early RCT demonstrating oral acyclovir significantly shortened duration of recurrent genital HSV lesions and viral shedding vs placebo.
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Acyclovir: a decade later
Perspective by Nobel laureate Elion summarizing acyclovir's selective mechanism via viral thymidine kinase activation, clinical utility spectrum, and safety profile.
3 published studies referenced in the app, each with a plain-language summary.