What are the main targets of antiviral therapy?
Host cell entry, Viral uncoating, Inhibit virus synthesis, and Virus Release
What enzyme is required for DNA chain elongation and propagation?
Which nucleoside base do many antiviral agents resemble in structure?
What virus does Acyclovir mainly deal with?
What does Acyclovir lack in order to be active?
3 phosphates (Acyclovir Triphosphate is what gets incorporated into the viral DNA)
What is the viral enzyme that first phosphorylates Acyclovir?
Herpes Thymidase Kinase
What is the end result of Acyclovir use?
Viral DNA polymerase inhibition and Viral DNA chain termination
What is the end result of Ganciclovir and its derivatives?
Viral DNA Polymerase Inhibition
What are AE associated with Acyclovir use?
Phlebitis and Nephrotoxicity (Crystalluria)
What should never been done with IV Acyclovir?
Never bolus it
Why does Valacyclovir not cause Phlebitis, while Acyclovir does?
Val is PO only
What is the key structural difference to Valacyclovir over Acyclovir?
Valene group added for increased bioavailability
What is unique about Penciclovir as a dosage form?
Only comes topically
What is unique about Famiciclovir as a dosage form?
Only comes PO
What is Famiciclovir converted to after absorption?
What are the three drugs that can be used to treat Herpes Simplex?
Acyclovir, Valacyclovir or Famiciclovir
What type of therapy is not effective in treating HSV?
How soon must episodic therapy of HSV be started in order to be efficacious?
within 24 hours of lesion outbreak
What is the goal of episodic therapy of HSV?
ameliorate/shorten duration of lesions
What is the goal of suppressive therapy of HSV?
decreases risk of transmission and reduces frequency of recurrences by 70-80%
What is the main drug used in suppressive therapy of HSV?
What are the two distinct clinical diseases associated with the Varicella-Zoster Virus?
Chickenpox (primary infection) and Herpes Zoster (Shingles)
What are symptoms associated with Chickenpox?
fever, malaise, rash - maculopapules, vesicles and crusted scabs
How does Chickenpox differ from impetigo?
Chickenpox is full body and has systemic symptoms
What can be done to relieve symptoms of Chickenpox?
Soothing bath for pruritis or APAP for fever
What is the main treatment for Chickenpox?
Acyclovir within 24 hours of lesion onset to reduce duration by 1 day and slow formation of new lesions
What populations should use Acyclovir to treat Chickenpox?
high-risk patients and adults
What causes Herpes Zoster?
reactivation of latent VZV in the dorsal root ganglia
What is unique about the presentation of lesions in Herpes Zoster?
Always presents as a horizontal stripe along a dermatome and never crosses the midline
What type of pain is associated with Herpes Zoster?
Acute neuritis (95%) and Postherpetic Neuralgia (Pain after 120 days)
What is the goal of antiviral therapy of Herpes Zoster?
Accelerate cutaneous lesion haling and Accelerate time to being pain free
What other class of drugs can be given besides antivirals to speed up healing from Herpes Zoster?
Corticosteroids (Prednisone) - controversial though
What are two non-antiviral medications that can be given to deal with the Postherpetic Neuralgia from Herpes Zoster?
Gabapentin or Pregabalin
What is the name of the Chickenpox vaccine?
Varivax Live Vaccine
What is the name of the Herpes Zoster vaccine?
Zostavax Live Vaccine
What patients should be using Ganciclovir or Valganciclovir?
Organ/stem cell transplants, chemo/oncology patients, immunosuppressed population
What is the spectrum of coverage for (Val)Ganciclovir?
HSV, VZV and CMV
What are the main AE associated with (Val)Ganciclovir?
Myelosuppression, Neutropenia, Thrombocytopenia, Mutagenic, Carcinogenic and Teratogenic
What is the only dosage form available for Foscarnet?
What is the main use for Foscarnet?
CMV-resistant to Ganciclovir
What is the MOA for Foscarnet?
pyrophosphate analog that binds to and inhibits viral DNA polymerase but is NOT incorporated into the viral DNA
What is it important to monitor in Foscarnet use?
Hydration (due to nephrotoxicity risk) and Electrolytes (due to chelation risk)
What is unique about Cidofovir's MOA?
Does not require the monophosphorylation step - goes straight to active diphosphorylate form to inhibit viral DNA polymerase
How often should Cidofovir be administered?
Weekly or Every Other Week but NEVER QD or QOD!
What is a common viral infection in which 70% of US cities' populations have it but are asymptomatic?
Which populations will CMV be a severe infection in?
Immunocompromised hosts - transplant patients / AIDS patients (Most common viral infection here)
What is the primary infection associated with CMV?
Infectious mononucleosis syndrome
What are secondary infections associated with CMV?
Re-infection from latent virus, Pneumonia (most severe), Retinitis (most common) and GI tract infections
What is the common first line therapy for CMV Retinitis?
Ganciclovir intraocular implant + Valganciclovir PO
What is common first line therapy for CMV Colitis/Esophagitis?
What is second line therapy for CMV?
Foscarnet or Cidofovir
What is the predominant cause of infectious mononucleosis?
What are symptoms associated with Epstein-Barr Virus?
Fever, Pharyngitis, Lymphadenopathy and Malaise/Fatigue
What cells will Epstein-Barr Virus invade?
B lymphocytes, converting them into 'immortal' proliferating cells
What can happen to patients with Epstein-Barr Virus who receive Amoxicillin?
pruritic maculopapular rash