Viruses And Antiviral Drugs Flashcards
What are the four routes that a virus can enter from in the body ?
- By inhalation through respiratory tract
- By ingestion via the GI tract
- Via the placenta from mother to infant
- Through inoculation (blood transfusions, sharing needles, organ transplants, sexual contact, bites,) via skin or mucous membranes
What are antivirals drugs?
Give examples of viruses.
Chemicals that kill or suppress viruses by destroying virions or inhibiting their ability to replicate to allow body to better fight viruses.
Specific or nonspecific
Ex of viruses: coronavirus, influenza, smallpox, chickenpox, HIV, AIDS (retroviruses), rhinovirus, etc…
What is the mechanism of action of antivirals (non-HIV)?
And examples of antiviral drugs (prototypes).
Work by impairing the viral replication by blocking activity of polymerase enzyme of the virus.
This causes a viral concentration low enough to allow the body’s immune system to eliminate the virus.
Ex of antivirals drugs: acyclovir (Zovirax)—> for herpes, Ganciclovir (Valcyte) —> for stronger viral infections , Oseltamivir (Tamiflu) —-> for influenza viruses
What are the general contraindications with antivirals therapy?
With acyclovir (Zovirax) and ganciclovir (valcyte)
Contraindications:
- pregnant/ lactating women
- children younger than 12months of age
- known severe drug allergy
- patient with severe kidney impairment
How do antivirals meds work best and why?
Why are immunocompromised pts more at risk?
In a patient with a competent immune system so the immune system can work synergistically with the deug to eliminate or suppress viral activity.
Pts who are immunocompromised (ex: cancer ptd, organ transplant pts or pts with AIDS) are at higher risk to develop an opportunistic infection .
Why are viruses harder to treat than bloodstream infections?
Because the viruses need to fusion to a host cell to be able to replicate meaning that the medication needs to be able to enter the host cell as well to kill the virus making it harder to be treated. Also because usually the virus has progressed a lot before symptoms appear so there is a larger viral concentration to be eliminated.
What are the types of herpes simplex virus ?
- herpes simplex virus 1 (HSV-1): oral herpes (perioral blisters)
- Herpes simplex 2 (HSV-2): genital herpes
- Human herpesvirus 3 (HHV-3) called Varicella-Zoster virus (VZV): chicken pox and shingles
- HHV-4 (Epstein-barr virus EBV): mono and chronic fatigue
- HHV-5 (cytomegalovirus CMV): CMV rinitis (serious eye infection and CMV disease in immunocompromised pts)
What are some indications for the use of acyclovir (Zovirax) anti-viral drug? And what is the mechanism of action?
Mechanism of action: synthetic nucleoside analogue suppressor: inhibitis viral replication by blocking DNA synthesis.
Indications: tx of Herpes Simplex virus type 1 and 2 (HSV-1 and HSV-2) and VZV (type 3 so varicella zoster virus)
Forms available of acyclovir?
PO, IV, topical or via injections
Most at risk for interactions with IV or PO administration
What are some AE with acyclovir?
- N&V
- diarrhea
- headache
- nephrotoxicity
- crystalluria
- burning of skin when applied topically
What are some AE of ganciclovir (synthetic nucleoside analogue anti viral)?
And its indications?
- bone marrow toxicity (suppression)
- nausea and vomiting
- headache
- seizures
Ganciclovir indications:
Tx of CMV (cytomegalovirus) or prevention of CMV in immunocompromised pts (pts receiving CMV positive organ in transplant)
What are some drug interactions with acyclovir?
- Interferon: additive anti viral effets
- probenecib: increased acyclovir levels due to decreased renal clearance
- zidovudine: increase risk of nephrotoxicity
What are some drugs interactions with ganciclovir (Valcyte) ?
What are the forms available?
- foscarnet: additive or synergistic effect against CMV and HSV-2 (genital herpes)
- Imipenem: increade risk of seizures
- zidovudine: increased risk for hematological toxicity (bone marrow suppression)
Available IV or PO
What are some important nursing implications with acyclovir?
- if topical: apply with gloves
- antivirals are not cures but help manage symptoms: need to be taken for full course and as prescribed
- po: take with food
- often PRN meds prescibed for acute episodes (take at first sign of reoccurence)
- IV: given slowly (over longer than 1h) and dont mix with other IVs
- abstein from sex as long as lesions are present
- encourage pt to drink plenty of fluids while on acyclovir infusion and after
Nursing implications with Ganciclovir?
- handle with gloves and goggles due to bone marrow toxicity effect
- not to be handled by a pregnant women
- assess blood counts prior to and during use due to bone marrow toxicity
- take with meals if taken PO
- administer into large veins to decrease irritation
What is the classification and mechanism of action of Oseltamivir (Tamiflu)/ Zanamivir?
What are the indications?
Classification: neuraminidase inhibitors
Works by inhibiting enzyme allowing the virus to spread in the body which speeds recovery.
Indications:
-acts against influenza A and B (decrease duration of illness) but must be given within 2 days of influenza symptoms
What are the AE of Oseltamivir (Tamiflu)/ Zanamivir?
And the forms available.
- N&V
Available only PO
Zanamivir available as powder for inhalation
What are some assessments needed to be done before giving acyclovir?
- assess VS
- thorough medication history
- pain levels associated with zoster lesions (since relief of pain is expected)
- hydration status
- kidney and liver function tests
What are some assessments neesed to be done before administering an antiviral drug?
- thorough head to toe assessment
- medical and medication history
- KDA
- patient’s nutritional status
- baseline VS
- assess for any contraindications and deug interactions
- assess energy levels
- assess for any weight loss
- assess for characteristics of any skin lesions
- if resp infection full resp assessment
Are oral antivirals best taken with or without food?
Take with meals to help minimize GI upset.
During an infusion of amphotericin B, the nurse knows that which administration technique may be used to minimize infusion-related AE?
A. Encourage fluids during the infusion.
B. Infusing the medication quickly
C. Infusing the medication over an extended period of time
D. Stopping the infusion for 2hrs after half of the bag has infused and then resuming 1hr later.
C.
A pt diagnosed with shingles is prescribed topical acyclovir (Zovirax). What important AE should the nurse warn this pt about?
A) insomnia and nervousness
B) temporary swelling and rash
C) burning of the skin
D) no AE
C)
Before administration of any antiviral medication, what nursing responsabilities would be performed? (Select all that applies)
A) assessment of baseline VS B) history of medication use C) head to toe physical assessment D) documentation of known allergies E) monitoring for medication AE
A, B, C & D
Not E bc that occurs AFTER administration not before
Through which of the following routes can viruses enter the body? (Select all that apply)
A) Through an animal bite
B) transplacentally from mother to infant
C) inhalation through respiratory tract
D) localized allergic reaction to medication
E) ingestion via the GI tract
A, B, C & E
