Poor
Mostly Misaligned
Patient Risk:
Moderate
Summary
Most claims provided are not supported by the supplied FDA label text for acyclovir, valacyclovir, famciclovir, penciclovir, or maribavir. The label excerpt only supports several acyclovir adverse reaction statements (nausea/vomiting, headache, fatigue/neurologic symptoms) and provides indications/dosing for acyclovir; numerous mechanism, prodrug/bioavailability, comparative efficacy/tolerability, dosing-frequency, and other drug/indication claims are unsupported.
Category Scores
Accurate Statements
Acyclovir can cause gastrointestinal issues such as nausea and vomiting.
Label (ADVERSE REACTIONS): nausea and/or vomiting reported; Digestive adverse events include nausea and gastrointestinal distress.
Acyclovir can cause neurological symptoms such as headache and fatigue.
Label (ADVERSE REACTIONS: Observed During Clinical Practice): headache listed under General; Nervous adverse events include somnolence and other CNS effects. The label excerpt does not explicitly list 'fatigue'.
Unsupported Statements
Prolonged use of acyclovir can lead to the development of resistant strains of HSV, reducing effectiveness.
Label excerpt discusses drug resistance and that possibility should be considered with poor clinical response, but does not support the specific phrasing that 'prolonged use' causes resistant strains to reduce effectiveness.
Acyclovir has poor oral bioavailability, requiring frequent dosing to maintain therapeutic levels.
Label excerpt provides average oral bioavailability (10% to 20%) but does not state 'requiring frequent dosing to maintain therapeutic levels.'
Valacyclovir is a prodrug of acyclovir.
No valacyclovir information is present in the supplied label text.
Valacyclovir has higher oral bioavailability than acyclovir.
No valacyclovir pharmacokinetic comparison is present in the supplied label text.
Valacyclovir allows for less frequent dosing than acyclovir.
No valacyclovir dosing-frequency information is present in the supplied label text.
Valacyclovir has been shown to be more effective than acyclovir for HSV infections.
No comparative efficacy information for valacyclovir vs acyclovir is present in the supplied label text.
Valacyclovir has been shown to be better tolerated than acyclovir for HSV infections.
No comparative tolerability information is present in the supplied label text.
Valacyclovir may cause gastrointestinal issues such as nausea and vomiting.
No valacyclovir adverse reaction information is present in the supplied label text.
Famciclovir is effective in treating HSV infections in immune compromised patients.
No famciclovir indication information is present in the supplied label text.
Famciclovir has a mechanism of action similar to acyclovir.
No famciclovir mechanism information is present in the supplied label text.
Famciclovir has a longer half-life than acyclovir, allowing for less frequent dosing.
No famciclovir half-life or dosing-frequency information is present in the supplied label text.
Famciclovir can be used to treat HSV infections in patients with HIV/AIDS.
No famciclovir HIV/AIDS indication information is present in the supplied label text.
Penciclovir is a topical antiviral cream.
No penciclovir formulation/indication information is present in the supplied label text.
Penciclovir cream is effective in treating genital herpes in immune compromised patients.
No penciclovir indication information is present in the supplied label text.
Topical application of penciclovir reduces systemic side effects.
No penciclovir safety/tolerability comparison is present in the supplied label text.
Topical application of penciclovir improves patient compliance.
No penciclovir compliance statements are present in the supplied label text.
Penciclovir cream is applied topically to the affected area.
No penciclovir administration instructions are present in the supplied label text.
Penciclovir cream is absorbed and exerts antiviral effects.
No penciclovir pharmacokinetic/pharmacodynamic statements are present in the supplied label text.
Maribavir is a novel antiviral medication.
No maribavir information is present in the supplied label text.
Maribavir has a mechanism of action distinct from acyclovir.
No maribavir mechanism information is present in the supplied label text.
Maribavir has been investigated as a potential alternative to acyclovir for HSV infections in immune compromised patients.
No maribavir/HSV investigation information is present in the supplied label text.
Other alternative treatments for HSV infections in immune compromised patients include brivudin.
No brivudin information is present in the supplied label text.
Brivudin is a nucleoside analog with antiviral activity against HSV.
No brivudin mechanism/activity information is present in the supplied label text.
Other alternative treatments for HSV infections in immune compromised patients include cidofovir.
No cidofovir information is present in the supplied label text.
Cidofovir is a nucleotide analog with antiviral activity against HSV.
No cidofovir mechanism/activity information is present in the supplied label text.
Other alternative treatments for HSV infections in immune compromised patients include ganciclovir.
No ganciclovir information is present in the supplied label text.
Ganciclovir is a nucleoside analog with antiviral activity against HSV.
No ganciclovir mechanism/activity information is present in the supplied label text.
Maribavir inhibits replication of HSV by targeting the viral DNA polymerase.
No maribavir mechanism information is present in the supplied label text.
Brivudin can be used to treat HSV infections in patients with compromised immune systems.
No brivudin indication information is present in the supplied label text.
Contradictions
Low
AI Statement
Acyclovir has poor oral bioavailability, requiring frequent dosing to maintain therapeutic levels.
Label Reference
Label (CLINICAL PHARMACOLOGY): average oral bioavailability is 10% to 20%; does not state that frequent dosing is required to maintain therapeutic levels.
Important Omissions
No safety/warning content from the acyclovir label is included (e.g., renal failure including death; TTP/HUS; oral suspension for oral ingestion only; contraindication to hypersensitivity to acyclovir or valacyclovir).
Importance:
Moderate
No acyclovir indication and approved dosing details are provided for the stated topics (herpes zoster, genital herpes, chickenpox; and renal impairment/dialysis dosing modifications).
Importance:
Moderate
Safety Assessment
Potential Patient Risk:
Moderate
Several claims involve other antivirals and comparative effectiveness/tolerability and dosing-frequency assertions that are unsupported by the supplied label text. Acyclovir adverse reaction claims for nausea/vomiting and headache are partially supported, but multiple potentially action-relevant statements are not label-supported.
Regulatory Assessment
| On Label |
No |
| Off-label Discussion |
No |
| Promotes Unapproved Use |
No |
| Hallucination Risk |
High |
Recommendation
Mostly Misaligned
Primary Issue
Large proportion of claims are unsupported because the supplied label text is for acyclovir and does not provide label data for valacyclovir/famciclovir/penciclovir/maribavir/brivudin/cidofovir/ganciclovir or for comparative and dosing-frequency assertions.
Suggested Improvement
Limit claims to the supplied acyclovir label excerpt: indications (herpes zoster, genital herpes, chickenpox), supported adverse reactions (nausea/vomiting; headache; other CNS effects), contraindication (hypersensitivity to acyclovir or valacyclovir), and supported pharmacokinetic info (oral bioavailability range) without adding unsupported causal language.