Antiviral Agents

Question 1

ANTIVIRAL AGENTS: action

Answer 1

Action – Work by interfering with viral replication.

Question 2

DRUGS FOR NON HIV VIRUSES

Acyclovir [Zovirax

Answer 2

Drugs – Acyclovir [Zovirax]*** – used for herpes simplex I & II, varicella-zoster, and herpes zoster. Decreases duration & severity of HSV attacks but does not prevent them.
Routes – PO or IV, topical.
Action – nucleoside analog which mimics one of the substances needed for DNA replication. Virus thus cannot reproduce. SE – local tissue irritation and damage, HA, N/V/D, reversible renal impairment

Question 3

DRUGS FOR NON HIV VIRUSES

Answer 3

Gancyclovir [Cytovene]* - treat CMV, retinitis.
Valacyclovir [Valtrex]* – herpes etc.
Docosanol –[Abreva] – for cold sores. topical – no systemic absorption – OTC
Cidofovir [Vistide] – CMV retinitis in pts with AIDS
Famciclovir [Famvir] – Genital herpes and shingles
Foscarnet [Foscavir] – IV – CMV & herpes

Question 4

DRUGS FOR NON HIV VIRUSES; Drug interactions

Answer 4

Drug interactions – several – including cytotoxic agents (e.g. CA drugs)

Question 5

DRUGS FOR NON HIV VIRUSES; Interventions

Answer 5

Interventions – watch for therapeutic and adverse effects. Advise pt of childbearing age to use contraception during and for at least 3 months after gancyclovir tx because it may cause mutations. Also don’t breast feed while on it.

Question 6

ANTI-VIRALS FOR FLU

Amantadine [Symmetrel]

Answer 6

Amantadine [Symmetrel]*** – used for influenza A virus in high risk groups. Must be given before attack or within 48 hrs. Can be given with flu shot to protect pt while immunity is developing. (also used for Parkinson’s disease – antidyskinetic).

Question 7

oseltamivir [Tamiflu]

Answer 7

oseltamivir [Tamiflu]** – also neuraminidase inhibitor.
Comes as a PO form. Also must be taken within 2 days of sx start. Taken BID x 5 days.
SE: N/V
Effect: Reduces time to Sx relief by about 1.3 days

Question 8

rimantadine [Flumadine]

Answer 8

rimantadine [Flumadine]* – like Symmetrel.

SE: NV, abd pain.

Question 9

Reverse transcriptase inhibitors

Answer 9

Reverse transcriptase is an enzyme needed by virus for DNA synthesis – not found in human cells. Drug mimics the nucleoside and fools the virus → cannot replicate. One of the classes always used in HAART. These are Prodrugs.

Question 10

Reverse transcriptase inhibitors: SE

Answer 10

SE: NVD, HA, fatigue during first few weeks.

Question 11

Reverse transcriptase inhibitors: SE II

Answer 11

Toxic to mitochondria – inhibit gamma-polymerase needed for DNA in mitochondria - can → lactic acidosis & severe hepatomegaly with steatosis syndrome. More common in women and with liver damage to start with. Get increased liver enzymes, fatty liver, maybe failure. SX: N, myalgia, RUQ pain.

Question 12

Reverse transcriptase inhibitors: SE III

Answer 12

Mitochondrial toxicity also → lipodystrophy. Face, arms, legs lose fat. Fat deposited on abdomen, breasts, and base of neck (buffalo hump).

Question 13

Zidovudine [AZT, Retrovir]

Answer 13

Drugs – Zidovudine [AZT, Retrovir]*** – For AIDS. Helps control opportunistic infections like PCP. Current dosing is Q12H.

Interactions: Many! Including ASA and Tylenol.

Question 14

Reverse transcriptase inhibitors: ADVERSS EFFECTS

Answer 14

Adverse effects: N/V/D/A, 
headache, 
fever, 
listlessness, 
skin rashes.  
potentially nephrotoxic.
 Can cause granulocytopenia, and anemia.  Also: dizziness, agitation, restlessness, insomnia, 
n/v/d/a, 
abdominal pain, 
dyspepsia, 
myalgia, 
diaphoresis, 
dyspnea, fever, rash, 
and taste perversion.

Question 15

Reverse transcriptase inhibitors INTERVENTIONS

Answer 15

Interventions: Take around the clock. Does not reduce risk of passing virus to others. Don’t use OTC drugs without checking with nurse first. Resistance develops in 3-6 mo if used alone.

Question 16

Reverse transcriptase inhibitors DRUGS

Answer 16

Drugs – abacavir [Ziagen]*
emtricitabine [Emtriva]*
lamivudine [Epivir]*
stavudine [Zerit]*
tenofovir [Viread]*

Question 17

NonNucleoside Reverse Transcriptase inhibitors [NNRTIs]

Answer 17

Action – Inhibit reverse transcriptase by binding close to it and changing its shape.

SE – Rash (can be Steven Johnson but rarely); can affect liver

Drugs – Efavirenz [Sustiva]***
Once daily dosage. High fat meals can → absorption 50% which can → toxicity- take on empty stomach.

Question 18

NonNucleoside Reverse Transcriptase inhibitors SIDE EFFECTS

Answer 18

SE at beginning – sleep disorders, nightmares, dizziness, decrease ability to concentrate, delusions.These slowly go away in about a month. But about ½ of all pts experience these.
Teratogenic.

Question 19

NonNucleoside Reverse Transcriptase inhibitors DRUGS

Answer 19

Delavirdine [Rescriptor]*
Nevirapine [Viramune]*
Etravirine [Intelence]*

Question 20

Protease inhibitors

Answer 20

Action – Work by inhibiting protease. Introduced in 1995 and revolutionized HIV.

SE – GI stuff. Lipodystrophy, increased cholesterol, maybe hyperglycemia and diabetes.

Question 21

Protease inhibitors KALETRA

Answer 21

Kaletra [lopinavir and ritonavir in combo pill]*** Approved 2000. Ritonavir inhibits the breakdown of lopinavir so much more is available. Much higher blood levels. Take once or twice daily. Drug of choice for first line Tx. Interacts with St. John’s wort → lower antiviral.

Question 22

Protease inhibitors SAQUINAVIR

Answer 22

Saquinavir [Invirase]* – First of these new drugs approved by FDA - in only 97 days! Should be used as part of combo tx with AZT, etc.

Question 23

Protease inhibitors

NELFINAVIR

Answer 23

Nelfinavir [Viracept]* – approved 1997.

SE: diarrhea (this is severe and most common problem), nausea, flatulence, rash,

Question 24

Protease inhibitors

Ritonavir [Norvir]

Answer 24

Ritonavir [Norvir]* – most likely to cause SE and toxicity problems. Used to “boost” blood levels of others – inhibits CYP 450 so others stay at higher levels.
SE: N/V/D/A, HA, fatigue, taste disturbances, circumoral (lip) paresthesia. Diarrhea often severe enough to → noncompliance.

Question 25

Indinavir [Crixivan]

Protease inhibitors

Answer 25

Indinavir [Crixivan]** – relatively safe and well tolerated. – give with high fat foods to increase absorption.
SE: Most impt SE is nephrolithiasis. Pts must drink large amts of fluids throughout the day. If stones develop, tx with hydration and analgesics – do not stop indinavir. Q8H dosing.

Question 26

Protease inhibitors

Answer 26

Atazanavir [Reyataz] – less effect on lipid levels
Darunavir [Prezista]
Fosamprenavir [Lexiva]
Tipranavir [Aptivus]

Question 27

Fusion Inhibitors

Answer 27

Interfere with fusion of viral and cellular membrances → block virus from getting into the host cell

Drugs – Enfuvirtide [Fuzeon]*** – 2003 – given SC BID. Has no effect on liver. Almost always get an injection site reaction at first: pain, pruritus, erythema, cysts, cellulitis.
Also NVD and fatigue and increased risk of pneumonia.

Question 28

Integrase inhibitors

Answer 28

2007 – without integrase, HIV can’t insert viral DNA into human chromosome.
Drugs – Raltegravir [Isentress]*** – PO.
SE: HA, GI stuff

Question 29

CCR5 inhibitors

Answer 29

CCR5 is one of the receptors HIV has to go through to get into cell. Blocking this reduces viral load.

Maraviroc [Selzentry]*** – po

SE – abd pain, cough, dizziness, fever, rash, URI, musculoskeletal problems. May get liver tox. May increase risk of MI.

Question 30

Gancyclovir [Cytovene]*

Answer 30

treats CMV, retinitis

Question 31

Valacyclovir [Valtrex]*

Answer 31

for herpes

Question 32

Docosanol –[Abreva]

Answer 32

for cold sores

topical – no systemic absorption – OTC

Question 33

Cidofovir [Vistide] – CMV retinitis in pts with AIDS

Answer 33

CMV retinitis in pts with AIDS

Question 34

Famciclovir [Famvir] – Genital herpes and shingles

Answer 34

Genital herpes and shingles

Question 35

Foscarnet [Foscavir] – IV – CMV & herpes

Answer 35

IV only – CMV & herpes

Question 36

ANTI-VIRALS FOR FLU
Amantadine [Symmetrel]
Action

Answer 36

Action: not completely clear – may prevent uncoating of virus and thus inhibit replication

Question 37

ANTI-VIRALS FOR FLU
Amantadine [Symmetrel]
Adverse effects

Answer 37

Adverse: N/A, nervousness, insomnia, fatigue, depression, anxiety, problems concentrating. Previous psych or abuse disorders can become worse. Seizures in pts with disorder.