NURA 221 EXAM 2 QUESTIONS AND
ANSWERS
6 characteristics of viruses
•Nonliving agents that infect bacteria, plants, animals
•Do not contain cellular organelles
•Have EITHER DNA or RNA (not both)
•Can be classified as intracellular parasites
•Must be in the host cell to replicate and cause infection (Many viruses infect
specific host cells)
•They do have their own enzymes which can be targeted with medications
What is the best "treatment" for viruses?
prevention
Describe self-limiting viruses
they require no treatment to be cured
i.e. rhinovirus, COVID
4 challenges of antiviral therapy
•Viruses mutate rapidly, and drug becomes ineffective
•Difficult for drug to find virus without injuring normal cells
•Each antiviral drug specific to one single virus (narrow spectrum)
•Antiviral drugs are clinically difficult to make and are very expensive
Herpes Virus
family of DNA viruses
,herpes simplex, varicella (chicken pox) and zoster (shingles) are the most common
cause repeated blister-like lesions on the skin, genitals, and other mucosal surfaces
How do antiviral drugs work on herpes?
•Antiviral drugs can lower the frequency of acute herpes episodes, diminish the
intensity of the acute disease
•Relieve acute symptoms, prevent recurrences
•Do not cure patients
Herpes medications
available as IV, PO, topical
prototype drug: acyclovir (Zovirax)
prevent viral DNA synthesis, work inside virus cell, slow and minimal absorption
decrease the duration/severity of herpes episodes
NOT a cure
Other herpes medications
•docosanol (Abreva)
•famciclovir (Famvir)
•valacyclovir (Valtrex)
•penciclovir (Denavir)
drug interactions to know for herpes treatment
a common one is with probenecid (Probalan), which treats gout
administration of herpes meds
administer around the clock, even if sleep is interrupted
side effects of herpes meds
•N/V/D, rash, dizziness, headache, fatigue, anaemia, elevated liver enzymes,
,dyscrasias
Dyscrasias
decrease in RBC, WBC and/or platelets
adverse effects of herpes meds
•few with topical & oral administration
•IV administration: nephrotoxicity & neurotoxicity
HIV
•HIV seeks T-cells, particularly CD4 cells
CD4 cells
needed for immune system function
a healthy individual has 800-1200 CD4/T-cells per cubic millimetre (mm3) of
blood
What do you want your CD4 count to be?
over 200
HIV viral load
undetected (<20) is goal.
The higher the number, the more virus present in the blood.
HIV medications
-Highly Active Antiretroviral Therapy (HAART)
-Antiretroviral Therapy (ART)
When to use HAART/ART
•Typically, only for HIV infection; some benefit with Hep B
•Prophylactic healthcare workers: injury (needle stick), CDC 0.3%
contraindications for ART
, •Severe allergy or intolerable toxicity
•CAUTIONS: Statin Drugs, Arrhythmia Drugs, Hepatitis C Drugs, Anti-Epilepsy
Drugs, TB Drugs
SE/AR of ART
•Short-term side effects/new meds: Headache, nausea, vomiting, sleep disturbance,
diarrhoea
• Long-term management: Renal function, cholesterol panel
Pregnancy and HIV
•Essential that pregnant individuals begin ART or maintain it during the entire
pregnancy
•Compliance essential
•Frequent monitoring of HIV and VL levels
chance of an HIV+ mother passing HIV to her unborn child if she takes ART?
<2%
explain the relationship between vaccination, antivirals and the flu
•Vaccination = prevention
•Antivirals to prevent, and decrease the severity of acute symptoms
flu medicines
•oseltamivir phosphate (Tamiflu)
•zanamivir (Relenza)
•peramivir (Rapivab)
•baloxavir marboxil (Xofluza)
When do you need to start antivirals for the flu?
within 48-72 hours