Ppt chapter 45

Chapter 45
Drugs Treating Viral Infections
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Question
• The transcription phase of viral replication involves the
change of RNA to DNA.
– A. True
– B. False

Answer
• A. True
• Rationale: Transcription involves the change of
ribonucleic acid (RNA) to deoxyribonucleic acid
(DNA).

Physiology of Viral Reproduction
• The reproduction of viruses in humans requires five
steps:
– Adsorption
– Penetration
– Uncoating
– Replication
– Transcription

Viral Reproduction

Pathophysiology of Selected Viral
Infections
• Cytomegalovirus (CMV)
– Type of herpesvirus
– Asymptomatic in most individuals
– Patients with AIDS or bone marrow transplant
recipients, CMV can be fatal.
– CMV infection during pregnancy may lead to birth
defect or stillborn.
– Most frequently causes retinitis, but also infects
lungs, throat, brain, kidneys, gallbladder, liver, and
colon

Infections (cont.)
• Hepatitis
– Five types: HAV, HBV, HCV, HDV, and HEV
– Most common in the United States: HAV, HBV, and
HCV
– Symptoms include jaundice, fatigue, abdominal pain,
nausea, and anorexia.
– HAV: spread via oral–fecal route
– HBV and HCV: spread via blood or body fluids

Infections (cont.)
• Herpes simplex (HSV)
– Two types: HSV-1 and HSV-2
– Characterized by the formation of painful vesicles;
HSV-1 on or near the mouth, HSV-2 in the genital
region
• Herpes zoster
– Acute unilateral and segmental inflammation of the
dorsal root ganglia caused by infection with the
herpesvirus varicella zoster (chickenpox)
– Follow dermatomes of trunk and occasionally on
arms and legs
– Postherpetic neuralgia is common complication.

Infections (cont.)
• Influenza
– Attacks both the upper and the lower respiratory tracts
– A and B only types affected by current antiviral agents
• Respiratory syncytial virus (RSV)
– A major cause of respiratory illness in all age groups
– Highest rates of RSV illness occur in infants 2 to 6
months of age
– Symptoms include hacking cough and wheezing on
exhalation.

Question
• Hepatitis A is spread through blood and body fluids that
contain blood.
– A. True
– B. False

Answer
• B. False
• Rationale: Hepatitis A is spread by the oral and fecal
route, not through blood or body fluids that contain
blood.

Purine Nucleoside Analogue Drugs
• The largest group of antiviral drugs is the purine
nucleoside analogue drugs.
• They have relatively selective toxicity to viruses because
viral DNA polymerases are more sensitive than human
polymerases to inhibition by these drugs.
• Prototype drug: acyclovir (Zovirax)

Acyclovir: Core Drug Knowledge
• Pharmacotherapeutics
– Treatment of herpesviruses
• Pharmacokinetics
– Administered: topical, oral, or IV
• Pharmacodynamics
– Undergoes phosphorylation. In an infected cell, it is
converted by the viral enzyme thymidine kinase.
Once incorporated into the virus, it terminates DNA
synthesis.

Acyclovir: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Use caution in patients with ganciclovir
hypersensitivity
• Adverse effects
– Light-headedness, anorexia, nausea, vomiting,
abdominal pain, and headache
• Drug interactions
– Valproic acid, hydantoins, theophyllines, and
probenecid

Acyclovir: Core Patient Variables
• Health status
– Assess medical history and function of kidneys.
• Life span and gender
– Pregnancy Category C drug
• Lifestyle, diet, and habits
– Can transmit disease to others
• Environment
– Assess the environment where the drug will be given.

Acyclovir: Nursing Diagnoses and
Outcomes
• Disturbed Thought Processes related to drug-induced
confusion, hallucinations, or seizures
– Desired outcome: The patient will be free of
thought aberrations related to drug therapy.
• Acute Pain related to drug-induced headache
– Desired outcome: Drug-related pain will subside
after administration of acetaminophen.

Acyclovir: Nursing Diagnoses and
Outcomes (cont.)
• Imbalanced nutrition: Less than Body Requirements,
related to acyclovir-related anorexia, nausea and
vomiting, or abdominal pain
– Desired outcome: The patient will remain within an
acceptable weight range.
• Excess Fluid Volume related to adverse effects of drug
therapy, such as nephrotoxicity
– Desired outcome: The patient will have an
adequate fluid intake and output profile.

Acyclovir: Planning and Interventions
• Maximizing therapeutic effects
– Administer acyclovir tablets or capsules with a full
glass of water, with or without food.
• Minimizing adverse effects
– Advise the patient to drink at least 8-oz glasses of
water a day.
– Administer IV acyclovir over 60 minutes.

Acyclovir: Teaching, Assessment, and
Evaluations
• Patient and family education
– Advise patients to notify the prescriber if they are
pregnant or breast-feeding.
– Emphasize that acyclovir does not prevent the
transmission of infection to another person and does
not cure the infection.
• Ongoing assessment and evaluation
– Monitor for the effectiveness of therapy, making sure
to document new lesions and assess for possible
secondary bacterial infections.

Question
• IV acyclovir is associated with which of the following
adverse reaction(s)?
– A. Hepatotoxicity
– B. Hallucinations
– C. Nephrotoxicity
– D. Seizures
– E. Both B and D

Answer
• C. Nephrotoxicity
• Rationale: Acyclovir nephrotoxicity appears to result
from crystallization of the drug in the nephron, which
can lead to renal tubular obstruction.

Drugs Used for Influenza
• Influenza can be a debilitating virus.
• It generally subsides without pharmacotherapy.
• Certain populations require treatment due to possible
life-threatening symptoms.
• Prototype: oseltamivir (Tamiflu)

Oseltamivir: Core Drug Knowledge
• Pharmacotherapeutics
– A neuraminidase inhibitor; used to manage influenza
A or B virus; drug of choice for H5N1 and H1N1
• Pharmacokinetics
– Metabolized: oseltamivir carboxylate. Excreted:
kidneys.
• Pharmacodynamics
– Appears to inhibit the release of viruses from infected
cells, reducing spread to adjacent cells

Oseltamivir: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Hypersensitivity, pregnancy, breast-feeding, asthma,
CAL, renal insufficiency
• Adverse effects
– Nausea and vomiting, bronchitis, insomnia, vertigo
• Drug interactions
– No known significant drug–drug interactions

Oseltamivir: Core Patient Variables
• Health status
– Assess for influenza symptoms.
• Life span and gender
– Pregnancy Category C drug
• Lifestyle, diet, and habits
– Assess for history of fructose intolerance.
• Environment
– Assess where the patient will be receiving the drug.

Oseltamivir: Nursing Diagnoses and
Outcomes
• Disturbed Thought Processes related to drug-induced
confusion, hallucinations, or seizures
– Desired outcome: The patient will be free of
thought aberrations related to drug therapy.
• Risk for Injury related to abnormal behaviors
– Desired outcome: The patient will remain free from
injury.

Oseltamivir: Nursing Diagnoses and
Outcomes (cont.)
• Imbalanced nutrition: Less than Body Requirements,
related to anorexia, nausea and vomiting, or abdominal
pain
– Desired outcome: The patient will remain within an
acceptable weight range.

Oseltamivir: Planning and Intervention
• Maximizing therapeutic effects
– Works best when started within 48 hrs of onset of
symptoms
– Prepare and store solution correctly.
• Minimizing adverse effects
– Reduce nausea and vomiting by administrating the
drug with milk, a snack, or a meal.

Oseltamivir: Teaching, Assessment, and
Evaluations
• Patient and family education
– Instruct on the correct usage.
– Encourage the patient to complete the full course.
• Ongoing assessment and evaluation
– Monitor for adverse effects.
– Assess for resolution of symptoms.

Question
• Which of the following symptoms are common for
influenza?
– A. Fever
– B. Joint aches
– C. Headache
– D. All of the above

Answer
• D. All of the above
• Rationale: Common signs and symptoms for
influenza can include sudden onset, fever, dry cough,
headache, muscle and joint aches, fatigue and
weakness, extreme exhaustion, chest discomfort,
stuffy nose, sneezing, and sore throat.

Ppt chapter 45

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