Acyclovir

• Acyclic guanosine analog that competes with deoxyguanosine triphosphate to inhibit viral DNA polymerase
• Resistance mediated by mutation in or decrease of thymidine kinase
• Good penetration into CNS and vitreous if administered intravenously, though not orally
• Adverse drug reactions include:
  • Acute kidney injury from crystal deposition, so maintain hydration
  • Phlebitis
  • Neurotoxicity, with lethargy, confusion, tremor, myoclonus, agitation, hallucinations, and extrapyramidal symptoms