Antiviral pharm PDF

Preview

Summary

good...

Description

Antiviral Antiretroviral Agents week 5 (Ch. 40) 

Review Key Terms: o

o

o

Viruses 

The smallest known class of microorganisms, viruses can only replicate inside host cells



Any organism that is infected with a microorganism, such as a bacteria or virus



A virus cant replicate on its own, it needs a host

Host

Genome 

o

Cell-mediated immunity 

o

One of two major parts of the immune system. It consists of nonspecific immune responses mediated primarily by T lymphocytes (T cells)

Humoral immunity 



The complete set of genetic material of any organism (DNA/RNA)

One of two major parts of the immune system. It consists of specific immune responses in the form of antigen-specific antibodies produced from B lymphocytes

Viral Illness o

Small pox (poxviruses)

o

Sore throat/conjunctivitis (orthomyxoviurses)

o

Respiratory (coronaviruses, rhinovirus)

o

Gastroenteritis (rotavirus, Norwalk-like virus)

o

Human immunodeficiency virus (HIV)= retrovirus

o

Acquired immune deficiency syndrome (AIDS)

o

Herpes (herpesviruses)

o

Hepatitis (hepadnaviruses) 

Effective drug therapy is available only for a small number of active viral infections 

 

HIV and all retrovirus

Some viral illnesses are survivable, some are life-threatening (always pay attention and seek medical treatment)

Antivirals o

Antivirals kill or suppress viruses by 

Destroying virions



Inhibiting replication 

Even the best medications never fully eradiate a virus completely from its host

 o

Immunoglobulins= drugs that actually destroy virions

o

Viral infections are more difficult to eradicate than bacterial infections 

o

Antivirals must enter cells to disrupt viral replication

Best response to antiviral drug therapy is seen in patients with competent immune systems 

Which patients might have the best response??? 



However the bodys immune system has a better chance of controlling or eliminating a viral infection when the ability of the virus to replicate is suppressed

Pts that have a healthy immune system b/c if the pt is immunocompromised the tx might not be great

Antiviral Drugs (NON-HIV)

Antivirals (Non-Human Immunodeficiency Virus) 

The drugs discussed in this section include those used to treat non-HIV viral infections such as those caused by influenza viruses, HSV, VZV, CMV, and hepatitis



Mechanism of Action and drug Effects o

Most of the current antiviral drugs work by blocking the activity of a polymerase enzyme

o

The result is impaired viral replication, which allows elimination of the virus by the pts immune system 



Indications o



Tx of HSV, VZV, CMV, and hep B & C

Contraindications o

Most antiviral meds used to treat non-HIV are well tolerated 



If this does not occur, the virus may either enter a formant state or remain a low level of replication with continuous drug therapy

Most common is severe drug allergy

Adverse Effects o

Each antiviral drug has its own specific adverse effects 

B/C viruses reproduce in human cells, selective killing is difficult, and consequently many healthy human cells, are killed with the bad owns 



Interactions o

2

Results in more serious toxicities for these drugs

Significant drug interactions arise most often when drugs are administered via systemic routes

 

Acyclovir (Zovirax)^^ o

Action Used mainly to suppress the replication of HSV-1, HSV-2, & VZV 

Pharmacologic Class Anti-Herpesvirus

o

Indication HSV-1, HSV-2 infections, including genital herpes, herpes zoster, chickenpox 

Evaluate Oral Bioavailability



Higher dose therapy for acute episodes



Lower dose therapy for viral suppression

Adverse Effects N & V, headache, burning when topically applied

Amantadine (Symmetrel) o

Action One of the earliest antiviral drugs, is only effective against influenza A viruses 



Used for both prophylactically and therapeutically, however the CDC does not recommend the use of amantadine to prevent or treat the flu

o

Pharmacologic Class Anti-Influenza

o

Contraindicated In lactating woman, children younger than 12 m of age, and pts with a eczematous rash

o

Indication Influenza A

o

Adverse Effects Dizziness, blurred vision, Insomnia, nervousness, lightheadedness, anorexia, orthostatic hypotension

Ganciclovir (Cytovene)^^ o

Action Tx of infections caused by CMV 



Drug of choice for the tx of both initial & recurrent episodes of this viral infections

o

o 

Many of these drugs are also applied topically, and the incidence of drug interactions associated is much lower

Also administered to prevent CMV disease (generalized infection) in high risk patients, such as those receiving organ transplants

o

Pharmacologic Class Antiviral

o

Indication CMV retinitis tx or maintenance

o

Adverse Effects Increased risk for hematologic toxicity (bone marrow suppression) & renal toxicity

Oseltamivir (Tamiflu)^^ o

Action

o

Pharmacologic Class Anti- Influenza

o

Indication Influenza A & B (given within 2 days of onset manifestation) 

o



Indicated for the tx influenza infection in adults



They have been shown to reduce the duration of influenza infection by several days



Tx needs to begging within 2 days of symptom onset

Adverse Effects Begin w/ in 2 days of onset of symptoms 

3

As soon as you give it, itwill decrease the amount of flue if you already have a cold for 5 days the drug will not help you

N & V, Diarrhea, sinusitis



Ribavirin (Virazole)^^ o

Action Interferes w/ both RNS & DNA synthesis and as a result inhibits both synthesis and viral replication overall 

If kid gets a little cold you might have to take him to PCP they might have RSV, If RN gets sick due to the kid having RSV, you don’t call it RSV anymore 

Which type of isolations would the nurse go into?? o

o

Pharmacologic Class Anti-RSV

o

Contraindicated  In pregnant woman and their male sexual partners and may be present in the body for up to 6 months after exposure

o

o 



Contact Isolatoin



At least 2 reliable forms of contraception must be used during tx and for 6 months after tx



Pregnant health care givers or those wishing to become pregnant must stay out of the pts rooms when aerosol form is being administered due to the potential of second hand inhalation

Indication Used primarily in the tx of hospitalized infants and toddlers w/ severe lower respiratory tract infections caused by severe RSV 

Give slow over 1h



Tx of Hep C

Adverse Effects Hepatotoxicity and lactic acidosis

Simeprevir (Olysio) o

Action Tx of chronic Hep C

o

Pharmacologic Class Protease Inhibitor

o

Indication Patients of eastern Asian ancestry exhibit higher levels of the drug and more adverse effects

o

Adverse Effects Photosensitivity, rash, nausea, and pruritis

Telbivudine (Tyzeka) o

Action Chronic Hep B 

Excreted by the kidneys and require dosage adjustments in pts with renal dysfunction

o

Pharmacologic Class Nucleoside Analogue Reverse Transcriptase Inhibitor

o

Indication  Severe acute Hep B exacerbations have been reported upon discontinuation

o

Adverse Effects Fatigue, headache, diarrhea, nausea, arthralgia, myalgia, myopathy, lactic acidosis, and hepatomegaly w/ steatosis

HIV/AIDS 

4

The most common routes of transmission of HIV are sexual activity, IV drug use, and perinatal transfer from mother to child. o

African American males and females have a higher HIV infection rate than whites.

o

Doesn’t transmit by casual contact, including hugging, kissing, coughing, sneezing, swimming pools, and sharing food, water and utensils.

o

Performing hand hygiene and maintaining standard precautions to avoid contact with all body fluids during pt care dramatically reduces the risk for caregiver infection

 o 

Pre-exposure prophylaxis (PrEP) id given when people are at very high risk for HIV (preventing HIV)

4-stages of HIV infection o

Tell the pt even though they are taking HIV meds is not a cure, what they do is control or reduce the viral load (slows down the progression)

o

Patient who are effectively treated with drug therapy typically do not progress through all these stages 



HIV infection that is untreated or tx resistance eventually leads to severe immune system failure with death secondary to opportunistic infections

o

Aids often progresses over a period of several years 

Stage 1 Asymptomatic infection



Stage 2 Early, general symptoms of disease



Stage 3 Moderate symp



Stage 4 Severe symp, often leading to death

Anti-retroviral drug therapy Greater numbers of long-term survivors

Highly active antiretroviral therapy (HAART) o

Combinations of anti-retroviral drugs (cocktails)

o

Now considered “Standard of care” to tx ppl w/ HIV 



o

HAART begins immediately upon confirmation of HIV infection

o

Opportunistic infections treated with infection-specific antimicrobial drugs

o

Prophylactic treatment for opportunistic infection is common

o

5

Normally begun immediately after confirmation of HIV infection, Dr. will start on cocktail to see which work best for that person

Drug Therapy





Or progression is slowed by years

o

o 

In the even of needle puncture, the HCP must receive prophylactic therapy

CD4 counts < 200 cells/mm

Opportunistic malignancies treated with antineoplastic medications

5-Classes of Antiretroviral Drugs o

Know the first 3 categories

o

Memorize all drugs for this



2- Subclasses of Reverse Transcriptase Inhibitors

HIV/AIDS Drugs o

o



Mechanism of Action o

Antiviral meds are used to tx od ppl who have HIV/AIDS

o

Reverse Transcriptase Inhibitors  work by blocking activity of the enzyme reverse transcriptase

o

Protease Inhibitors work by inhibiting the protease retroviral enzyme

o

Fusion inhibitors work by inhibiting viral fusion 

Can cause irritation, rotate the administration site and the different techniques wheadministering medications



Evidence of drug resistance includes falling CD4 count and/or increased viral load



A viral load of less than 50 is considered to be an undetectable viral load and is the primery goal of antiretroviral therapy

Indications o

Active HIV infection, a few are also used to treat Hep B

o

Prophylactic antiretroviral tx of infected mothers has been shown to reduce infant infection

o

Meds might also be given prophylactically to the newborn infant, typically for the first 6 wks of life

Enfuvirtide (Fuzeon) o

Action Works by suppressing the fusion process and subsequent viral replication

o

Pharmacologic Class Fusion Inhibitor

o

Interactions Prevent viral replication 





Indinavir (Crixivan) o

Pharmacologic Class Protease Inhibitor

o

Interactions Best dissolved and absorbed in acidic environments and presence of high protein fat foods reduces its absorption 

Therefore, it is recommended it is administered in a fasting state



Commonly administered w/ reverse transcriptase inhibitors to maximize efficacy and decrease resistance

Maraviroc (Selzentry) o

Pharmacologic Class CCR5 Antagonist

o

Indication Used in tx existing pts w/ evidence of viral replication 

o 

Pts must receive an FDA approved medication guide before this drug is dispensed

Adverse Effects Hepatotoxicity, and significant

Nevirapine (Viramune) o

6

Used in combination with other drugs to prevent drug resistance

Pharmacologic Class Nunmucleoside reverse Transcriptase Inhibitor

o



Indications Most common adverse effects are nausea, fever, rash, headache, and abnormal liver function tests

Raltegravir (Isentress)



o

Pharmacologic Class Integrase Inhibitor

o

Indications Used to treat experienced patients with virus that shows multidrug resistance and active replication

o

Adverse Effects Myopathy and rhabdomyolysis, as well as immune reconstruction syndrome (not on ppt)

Tenofovir (Viread)



o

Pharmacologic Class Nucleotide Reverse Transcriptase Inhibitor

o

Indications Tx of HIV in combination w/ other antiretroviral HIV drugs

o

Adverse Effects Lactic Acidosis and severe hepatomegaly

Zidovudine (Retrovir) o

Pharmacologic Class Nucleoside Reverse Transcriptase Inhibitor

o

Indication First HIV drug 

Prescribed for pregnant woman and newborn to prevent maternal transmission of the virus to the infant



Dose limiting adverse effect is bone marrow suppression

Nursing Process: Assessment o

Head-to-toe assessment

o

Assess and document allergies (sulfa)

o

Assess nutritional status

o

Assess baseline vital signs

o

Evaluate over-the-counter (OTC) medication use

o

Assessment of labs (CBC, CMP, pregnancy test, renal function, liver function, sputum)

o

Previous medical history

o

Assess patient knowledge level

o



Asses for allergies and nutritional status b/c HIV pts can have wasting syndrome, N & V, will not have a good apetite and then you will start to have weight loss from the profound effects



Baseline V/S are always imp, Assess labs and CBC



CBC= look at RBC, Platelets, and WBC, because of bone marrow suppression

Renal function 

o 

7

Some drugs can cause either the pt to have problems or even a pt who has never taken it before could accumulate the meds and lead to nephron toxicity

First time HIV pt psychological assessment is very imp to assess

Nursing Process: Implementation (NON-HIV) o

Appropriate techniques

o

Hand washing  best way to prevent the spread of infection





8

o

Standard precautions

o

Monitor for superinfections If you get treated

o

Take with meals to prevent GI upset

o

Do not crush capsules

o

Use finger cot or gloves with topical preparations

o

Parenteral forms must be given slowly over 1 hour or more to prevent renal tubular damage

o

Encourage adequate hydration during infusion and after to prevent crystalluria

o

Carefully monitor infusion site

o

Common adverse effects of acyclovir are nausea, diarrhea and headache

o

Suck on sugarless candy for dry mouth

o

Monitor for orthostasis

o

Educate about photosensitivity

Nursing Process: Implementation (HIV Antiretroviral) o

Monitor labs

o

Monitor for s/s of opportunistic infection

o

Remain upright for 30 minutes to avoid esophageal ulceration

o

Continuous monitor of labs

o

Assess IV preparations for sediment/precipitate

o

Ensure steady-state: administer at evenly spaced intervals

o

Provide patient centered teachings

Nursing process: Evaluation o

Monitor for adverse effects

o

Monitor for therapeutic effects

o

Monitor for toxicity

o

Reevaluate and modify the plan of care as needed

9

10

11

12

13...