Poor
Poorly Aligned
Patient Risk:
Low
Summary
The AI claims largely exceed or diverge from the label. Acyclovir–antibiotic interaction statements are largely unsupported; several core safety, indication, pharmacokinetic, and dosing specifics align only partially (e.g., renal dosing, probenecid interaction, pregnancy category B, basic indications). Multiple asserted co-prescription claims are not supported by the labeling, resulting in substantial misalignment.
Category Scores
Accurate Statements
Acyclovir is indicated for herpes zoster, genital herpes, and chickenpox.
INDICATIONS AND USAGE
Acyclovir is renally excreted and requires dosage adjustment in renal impairment.
Dosage and Administration; Clinical Pharmacology
Acyclovir plasma protein binding ranges from 9% to 33%.
Clinical Pharmacology (Table 1)
Acyclovir has a plasma elimination half-life of approximately 2.5 to 3.3 hours.
Clinical Pharmacology (Table 1)
Oral bioavailability of acyclovir is about 10% to 20%.
Clinical Pharmacology (Table 1)
There was no effect of food on absorption of acyclovir; it may be taken with or without food.
Clinical Pharmacology (Table 1 discussion)
Probenecid increases acyclovir exposure by reducing renal clearance.
Clinical Pharmacology (Pharmacokinetics); Drug Interactions
Table 3 provides dosage modifications for renal impairment.
Dosage and Administration
Acyclovir is categorized as Pregnancy Category B.
Pregnancy
Geriatric notes indicate possible dose reduction with renal impairment.
Geriatrics
Pediatric pharmacokinetics of acyclovir are generally similar to adults; specific half-life data exist for children.
Pediatrics
Bioequivalence of formulations (oral suspension to capsules) is described.
Bioequivalence
Unsupported Statements
Acyclovir can generally be taken with antibiotics.
Label does not provide a blanket co-prescription endorsement with antibiotics; absence of explicit guidance is a safety gap.
No major drug interactions are reported between acyclovir and common antibiotics like amoxicillin, azithromycin, or ciprofloxacin.
Label does not explicitly state no significant interactions with antibiotics.
Acyclovir and antibiotics are often prescribed together for overlapping infections such as viral herpes with bacterial skin issues.
Indications do not endorse routine concurrent antibiotic co-therapy with acyclovir.
Penicillins have no interaction with acyclovir.
Label does not state penicillin–acyclovir interactions; no data on this specific interaction.
Penicillins are frequently co-prescribed with acyclovir.
Label does not address frequency of concomitant penicillin use with acyclovir.
Macrolides are safe with acyclovir.
No explicit macrolide interaction data are provided in Drug Interactions.
Acyclovir doesn't affect the efficacy of macrolides.
No label data confirming lack of interaction affecting antibiotic efficacy with macrolides.
Fluoroquinolones are compatible with acyclovir.
No explicit compatibility statement in Drug Interactions.
Acyclovir and fluoroquinolones can stress kidneys; monitor in elderly patients.
Label notes nephrotoxicity with IV acyclovir and renal impairment, but does not specify combined nephrotoxicity with fluoroquinolones.
CDC guidelines support concurrent use without dose adjustments.
Label-based dosing guidance should drive dosing; external guidelines are not a label data source.
IDSA guidelines support concurrent use without dose adjustments.
Same as above; not label-supported.
In kidney impairment, both acyclovir and antibiotics can accumulate.
Label addresses acyclovir accumulation; does not discuss accumulation risk for co-administered antibiotics.
Acyclovir allergies do not cross-react with antibiotics.
Label does not discuss cross-reactivity between acyclovir allergy and antibiotics.
Most antibiotics are compatible with acyclovir during pregnancy.
Label provides no guidance on antibiotic compatibility during pregnancy.
Acyclovir is used for herpes viruses.
Statement overly broad; label lists specific herpes viruses (HSV, VZV) and indications.
Contradictions
Important Omissions
No explicit label guidance that acyclovir has no clinically significant interactions with most antibiotics; no quantified safety statement for co-prescription.
Importance:
Moderate
No label statement that penicillins (e.g., amoxicillin) have no interaction with acyclovir; no concomitant-use guidance.
Importance:
Moderate
No explicit macrolide-acyclovir interaction data; no definitive safety assertion for macrolides (e.g., azithromycin) with acyclovir.
Importance:
Moderate
No label guidance on antibiotic interactions during pregnancy beyond general pregnancy category; no specific compatibility data.
Importance:
Moderate
No cross-reactivity data for acyclovir allergy with antibiotics; allergy considerations are not addressed.
Importance:
Moderate
No label references to CDC/IDSA guidelines for concurrent use; dosing should be based on labeling rather than external guidelines.
Importance:
Moderate
No explicit discussion of nephrotoxicity risk when combining acyclovir with nephrotoxic antibiotics; no combined risk data.
Importance:
Moderate
Monitoring recommendations beyond renal dosing adjustments are limited; no specific monitoring guidance for co-therapy with antibiotics.
Importance:
Moderate
Safety Assessment
Potential Patient Risk:
Low
Label documents renal impairment risks and TTP/HUS in immunocompromised; overall risk with labeled uses is moderate, but extrapolated claims about antibiotic combinations increase safety ambiguity.
Regulatory Assessment
| On Label |
Yes |
| Off-label Discussion |
No |
| Promotes Unapproved Use |
No |
| Hallucination Risk |
Low |
Recommendation
Poorly Aligned
Primary Issue
Multiple statements about antibiotic co-therapy with acyclovir are not supported by the label and several safety/dosing points are not adequately addressed.
Suggested Improvement
Align claims with label: restrict statements to label-supported indications and pharmacokinetics; remove broad assertions about antibiotic compatibility; emphasize renal dosing controls and avoid extrapolations from external guidelines.