Antiviral Drugs Med class- Quiz 2 Flashcards
Virus Overview
-Are intracellular parasites
-They use much of the metabolic processes of the host— very few drugs selective enough to prevent viral replication without injuring the infected individual
-Treating viral illness is complicated by the fact that symptoms appear late in the course of illness—after the virus has replicated—so drugs that prevent replication are not helpful
Respiratory viruses can be treated by which antivirals?
- Neuraminidase inhibitors (Tamiflu)
- Ribavirin
- Remdesivir
Neuraminadase Inhibitors
-Effective against flu A and B
-Given prior to exposure, they prevent infections and when given 24-48 hours after symptoms occur, they decrease the intensity and duration of the illness
-MOA: Flu viruses rely on a neuraminidase enzyme to release newly formed viruses.Neuraminidase inhibitors selectively block this enzyme, preventing the release of new virions and limiting the spread.
-ADE’s: GI discomfort and nausea
-Oseltamivir= PROTOTYPE drug
-Ex. Zanamivir (inhaled drug– use with caution w/ COPD/ asthma potential for bronchospasm)
Adamantane antivirals
-Only works for Flu A
-NOT recommended for prophylaxis or treatment in the US d/t resistance
Ribavirin
-Effective against a broad spectrum of RNA and DNA viruses
-Used in treatment of immunosuppressed kids with RSV
-MOA: Inhibits replication of RNA and DNA viruses
-Effective orally and by inhalation
-ADE’s: dose dependent transient anemia, elevated bilirubin
-CI: pregnancy
How do you treat Hep B?
- Interferons:
-Naturally occurring glycoproteins that interfere with virus’ ability to infect the host cells
-MOA: Incompletely understood, thought to inhibit viral RNA translation
-Use: Peginterferon alpha-2a is approved for tx of chronic Hep B
-ADE: flu like symptoms, fatigue, depression
-Dose limiting: Bone marrow toxicity,
severe fatigue, weight loss, somnolence, autoimmunity
2.Lamivudine: NO LONGER RECOMMENDED (STUPID)
- Adefonir: NO LONGER RECOMMENDED (STUPID)
- Entecavir: Treatment of HBV
-Don’t use with other drugs that cause renal toxicity
What is needed for the treatment of Hep C?
-Combination DAAs (Direct activating antivirals)
What is used to Treat Hep C?
-There’s WAY too many of these– they all end in “VIR”
-NS3/NS4A Protease Inhibitors; -MOA: Inhibiting this protease halts RNA replication
-ADEs—rash, itching, nausea, fatigue, anemia
-NS5B polymerase inhibitors:
-MOA: NS5B is only RNA polymerase responsible for Hep V replication
-MOA; these inhibit it
-ADEs—few; well tolerated
-NS5A replication complex inhibitors:
-MOA: NS5A is a viral protein necessary for Hep B RNA replication and assembly– inhibits this
-Many drug-drug interactions
-Riboravin: Approved for Hep C when used WITH an interferon or DAA
-MOA: Unknown
NOTE* Cirrhosis status is important when prescribing these*
-Ex: Elbasvir+ grazoprevir
Glecaprevir + pibrenasvir
Acyclovir
-Is the PROTOTYPE antiherpetic drug
-Covers HSV1, HSV2, VZV and some
strains of Epstein-Barr virus
-Used in: HSV ENCEPHALITIS
-Most common use= genital herpes
-MOA: Causes premature DNA chain termination
-Pharm: Oral, IV, topical (does accumulate in renal failure)
-Distributes well throughout the body, including CSF
-ADE’s: (Depends on route of
administration)
-Headache, diarrhea, nausea
and vomiting
-Transient renal dysfunction w IV
Cidofovir
-Indicated for CMV retinitis in patients
with AIDS
-MOA: —inhibits viral DNA synthesis
-ADE: Given IV—causes renal toxicity;
contraindicated in those with pre-existing renal problems
-Also, Neutropenia and metabolic acidosis can occur
Foscarnet
-Used for CMV retinitis in the
immunosuppressed and or
Acyclovir resistant HSV
-MOA: Works by reversibly inhibiting viral DNA and RNA polymerases
-Poorly absorbed after oral dose; must be given IV (give frequently to avoid relapse when plasma levels fall)
-ADEs—nephrotoxicity, anemia, nausea, fever; low Ca++ and Mg+, low
K+, phosphate abnormalities, seizures, arrhythmias
Gancyclovir
-An analog of acyclovir that has greater activity against CMV
-Used in: the treatment of CMV
retinitis in the immunosuppressed
and to prevent CMV in transplants
-MOA: DNA chain termination
-Given IV and distributes
throughout the body and CSF
-ADE’s: Severe neutropenia
-BLACK BOX: Carcinogenic
and teratogenic in pregnancy
Penciclovir and Famciclovir
-Topical + oral (respectively)
-Minimally absorbed after topical use; well tolerated
-Effective orally; ADEs are
headache and nausea
-Used in: acute Herpes Zoster, genital
HSV infection, and recurrent Herpes labialis
Trifluridine
THIS ONLY COMES IN EYE DROPS WTF WASNT IT THE EYE ANTIBIOTIC SECTION
-Treats: HSV keratoconjunctivitis and epithelial keratitis
