Ppt chapter 45

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 45

Drugs Treating Viral Infections

Chapter 45

Drugs Treating Viral Infections


QuestionQuestion

• The transcription phase of viral replication involves the change of RNA to DNA.

– A. True

– B. False


AnswerAnswer

• A. True

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


Physiology of Viral Reproduction Physiology of Viral Reproduction

• The reproduction of viruses in humans requires five steps:

– Adsorption

– Penetration

– Uncoating

– Replication

– Transcription


Viral ReproductionViral Reproduction


Pathophysiology of Selected Viral Infections 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


Pathophysiology of Selected Viral Infections (cont.)Pathophysiology of Selected Viral 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


Pathophysiology of Selected Viral Infections (cont.)Pathophysiology of Selected Viral 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.


Pathophysiology of Selected Viral Infections (cont.)Pathophysiology of Selected Viral 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.


QuestionQuestion

• Hepatitis A is spread through blood and body fluids that contain blood.

– A. True

– B. False


AnswerAnswer

• 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 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 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.)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 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 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.)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 InterventionsAcyclovir: 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 EvaluationsAcyclovir: 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.


QuestionQuestion

• 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


AnswerAnswer

• 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 InfluenzaDrugs 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 KnowledgeOseltamivir: 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.)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 VariablesOseltamivir: 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 OutcomesOseltamivir: 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.)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 InterventionOseltamivir: 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 EvaluationsOseltamivir: 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.


QuestionQuestion

• Which of the following symptoms are common for influenza?

– A. Fever

– B. Joint aches

– C. Headache

– D. All of the above


AnswerAnswer

• 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.

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Ppt chapter 45