NCM 206: PHARMACOLOGY
LECTURE: ANTI-VIRAL
1st SEMESTER │A.Y. 2022 – 2023
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ANTI-VIRAL
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More difficult to treat than bacterial
infections because virus depends on
blochemical processor of the host cells for
its replication
Drugs that interfere with virus may also
damage cells
MOA: inhibit viral replication by interfering
viral nucleic acid synthesis in the cell
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CI: CNS disorders, allergy, pregnancy &
lactation, renal disease
 SE: N/V, HA, depression, rash, hair loss,
inflammation & burning sensation at the site
of injection and topical
 AE: renal dysfunction
 DI:
o + other nephrotoxic meds inc toxicity
o +zidovudine inc drowsiness
AGENTS FOR INFLUENZA AND RESPIRATORY
VIRUSES
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Eg.
o amantadine (Symmetrel) - PO
o oseltamivir (Tamiflu) - PO
o ribavirin (Virazole) - aerosol inhalation
o rimantidine (Flumadine) - PO zanamivir
(Relenza) - inhaler
 Cl: allergy, pregnancy & lactation.renal &
liver disease
 AE: lightheadedness, dizziness, insomia,
nausea, orthostatic hypotension, & urinary
retention
 DI: with anti-cholinergic drugs = increase
atropine like effect
TOPICAL ANTIVIRALS (HSV)
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Start regimen as soon after the exposure to
the virus as possible (achieve best
effectiveness and decrease the risk of
complications)
Administer the full course of drug
Provide safety measures (protect patient
from injury)
AGENTS FOR HERPES
idoxuridine
Penciclovir
trifluridine
Nursing Considerations:
Nursing Considerations:
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foscarnet (Foscavir) = both; IV
ganciclovir (Cytovene) = long term
treatment & prevention of CMV; IV
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Extreme caution to children (carcinogenic);
foscamet ( affect bone growth &
development)
Good hydration (decrease toxic effects o
the kidney)
Administer as soon as possible, compliance
Wear protective gloves when applying the
dug topically (decrease risk of exposure to
the drug and inadvertent absorption)
Safety precautions CNS effects (orientation,
siderails, lighting, assistance)
Warn that Gl upset. N/V can occur (prevent
undue anxiety, increase awareness of the
importance of nutrition)
Monitor renal function.
Avoid sexual intercourse if with genital
herpes
Avoid driving and hazardous tasks if with
dizziness & drowsiness
Herpesviruses
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Herpes simplex virus type 1
HSV2
HSV3: Varicella-zoster (chickenpox or
shingles)
HSV 4: Epstein-Barr virus
CMV: cytomegalovirus
Examples:
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acyclovir (Zovirax), famciclovir (Famvir),
valacyclovir (Valtrex) = herpes; PO
cidofovir (Vistide) – IV = CMV in AIDS
MIDTERMS │3 UNITS
AGENTS FOR HIV & AIDS
Enzymes needed by viruses:
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Reverse transcriptase – helps uncoat the
virus; single stranded viral RNA is
converted into DNA
Integrase – helps viral DNA migrates into
the nucleus of the cell, where I is spliced
into the host DNA (provirus) duplicated
together with the cell genes every time the
cell divides
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Protease – assists in the assemble of newly
formed viral particles
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Empty stomach/low fat meal (prevent
excessive drug absorption)
NUCLEOSIDE/ NUCLEOTIDE REVERSE
TRANSCRIPTASE INHIBITORS (NRTIS)
nevirapine (Viramune) - alternative
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MOA: blocks the reverse transcriptase
enzyme needed for viral replication
zidovudine (Retrovir)
didanosine (Videx)
stavudine (Zerit)
lamivudine (Epivir)
abacavir (Ziagen)
tenofovir (Viread)
emtricitabine (Emtrive)
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Pregnancy (1st tri)
Planning to conceive
Not using effective/ consistent contraception
<risk: rash hepatotoxicity
delavirdine (Rescriptor)
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Least potent antiviral activity
Not recommended as part of regimen
Fixed dose:
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lamivudine/zidovudine (Combivir)
abacavir/lamivudine/ zidovudine (Trizivir)
abacavir/lamivudine (Epzicom)
efavirenz/ emtricitabine/tenofovir (Atripla)
emtricitabine/ tenofovir (Truvasa)
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SE (less tenofovir – renal toxicity)
Gl: nausea, diarrhea, abdominal pain
(transient-2 weeks)
Mitochondrial toxicity: lactic acidosis,
peripheral neuropathy, myopathy,
pacreatitis, lipoatrophy (wasting of fats in
face, buttocks and extemities)
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Nursing Considerations:
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Should be taken with food except
didanosine (60 min AC or 2 hours PC)
Requires dosage adjustment except
abacavir (creatinine clearance < 50mL/min)
Fixed dose avoided if with renal
insufficiency
NON-NUCLEOSIDE REVERSE TRANSCRIPTASE
INHIBITORS (NNRTIS)
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MOA: prevent viral replication by competing
with binding of the revere transcriptase
enzyme at the active site
Used to reserve protease inhibitors
(resistance)
Eg.
efavirenz (Sustiva)
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First-choice drug
PC: D
CNS toxicities: dizziness, sedation,
nightmares, euphoria, loss of concentration
Administered as a component of Atripla
OD@HS
MIDTERMS │3 UNITS
PROTEASE INHIBITORS
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MOA: act at the end of the HIV cycle to
inhibit the production of infectious HIV virus
lopinavir/ritonavir (first line)
atazanivir
fosamprenavir (second either boosted with
retonavir or not)
amprenavir
tipranavir
darunavir
saquinavir
indinavir
ritonavir
nelfinavir
NOTE:
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Ritonavir boosting - mainstay of PI therapy
(potent inhibitory effect)
Take with food
+ didanosine one hr before or two hours
after ritonavir
ENTRY INHIBITORS
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MOA: prevents HIV cell entry (fusion of HIV
and CD4)
enfuvirtide – the only agent approved
Indicated in combination with 3-5 other antiretroviral agents (for clients with limited
treatment option)
Expensive. 90 mg Sub-Q. BID
Injection site reaction:
o Subcutaneous nodules, redness
o Others: rash. Diarrhea, serous allergic
reaction (anaphylaxis)