Antivirals and Antifungals Flashcards
What is an example of an M2 ion channel inhibitor? What is it used for?
Amantidine for prevention (70%) and treatment (20-30% reduction) of the influenza A virus
How does an M2 ion channel inhibitor work?
Blocks the M2 transmembrane ion channel, which prevents uncoating of the virus (essential in replication)
Virusatic
What are some adverse effects of M2 ion channel inhibitors?
Dose related, amphetamine like, mild GI upset
Rapid resistance
2:1 therapeutic index (toxic)
What is an example of a neuraminidase inhibitor? What is it used for?
Zanamivir and Oseltamivir (inhaled powder) are used for prevention (70%) and treatment (20-30% reduction) of influenza A and B infection.
How do neuraminase inhibitors work?
Inhibits viral neuraminidase, impairing the release and spread of influenza virions from infected cells due to aggregation of virions.
What are some adverse effects of neuraminase inhibitors?
Zanamivir may rarely cause bronchospasm.
Ostelamivir causes mild nausea and vomiting
What is an example of a DNA polymerase inhibitor? What is it used for?
Acyclovir, valacyclovir, famcicolvir
Treatment, prevention and supression of HSV and VZV infection of skin, mucous membranes and viscera.
Ganciclovir only for GMV
How do DNA polymerase inhibitors work?
Competitively inhibit DNA polymerase by acyclovir phophorylation and causes DNA chain termination
How does resistance to DNA polymerase inhibitors occur?
Only develops in immunocompromised patients during prolonged therapy due to mutation of an enzyme, thus reduced affinity.
What are some adverse effects of DNA polymerase inhibitors?
Rapid IV administration (acyclovir) can cause crystallization, leukopenia (GCV) and allergy (topicals)
Which DNA polymerase inhibitor is used in pregnant patients?
Acyclovir and vacyclovir
Which DNA polymerase inhibitors are used for HSV keratitis in the eye?
Idoxuridine, trifluridine, vidarabine
Can cause local irritation or corneal dystrophy if prolonged exposure
What is an example of a biological immune response modifier? What are they used for?
Imiquimod (topical) and interferon-alpha 2b (injection) to treat genital HPV infection (warts)
Podophyllin is ablative
How do biological immune response modifiers work?
Activates immune cells (monocytes, macrophages, NK cells) to produce antiviral cytokines (IFN-alpha and TNF)
What is the efficacy of biological immune response modifiers?
Imiquimod clears warts in 37-52%
Interferon-alpha 2b clears warts in 42-62%
What are some adverse effects of biological immune response modifiers?
Local irritation, erythema, ulceration, scabbing (must wash off residual drug after overnight application) for topical therapy
Pain, local irritation at injection site
What are some examples of provider administered biological response modifiers?
Cryotherapy, podophylline resin, trichloroacetic acid, excision, intralesion IFN
What are the 6 classes of drugs for HIV infection?
Fusion inhibitor, CCR-5 Coreceptor antagonist, nucleoside reverse transcriptase inhibitor (NRTI), non-NRTI, integrase inhibitor, protease inhibitor
What is an example of a fusion inhibitor?
Enfuvirtide (subcutaneous injection) to treat HIV-1
Eliminated by proteolysis
What is maraviroc?
A CCR-5 Coreceptor antagonist used to treat HIV-1 orally. Should be last utilized for therapy
Eliminated by liver
What are some examples of NRTIs?
Zidovudine, lamivudine, stavudine, dideoxycytidine used to treat HIV-1 and 2
Eliminated by liver and renal
What are some examples of NNRTIs?
Efavirenz, delavirdine, nevurapidine used to treat HIV-1 orally
Eliminated by liver
What is an example of integrase inhibitors?
Raltegravir
Used to treat HIV-1 orally
Elminated by glucuronidation
What are some examples of protease inhibitors?
Saquinavir, ritonavir, infinavir
Used to orally treat HIV-1 and 2
Eliminated by liver
How do fusion inhibitors work?
Inhibits gp41-mediated fusion of virus with CD4 lymphocyte cell membrane (stops HIV entry into CD4 cells)
What are some adverse effects of fusion inhibitors?
Local inflammatory reactions at injection site, diarrhea, nausea
How do CCR-5 coreceptor antagonists work?
Binds to CCR-5 on the macrophage and CD4 cell to stop viral entry
What are some adverse effects of CCR-5 coreceptor antagonists?
Drug interactions, hepatotoxic (rash, eosinophilia or elevated IGE),
How do NRTIs work?
Inhibits RNA-dependent DNA polymerase (reverse transcriptase) by binding to the enzyme. DNA chain terminator
What are some adverse effects of NRTIs?
Inhibition of the mitochondrial DNA polymerase causing lactic acidosis, hyperlactemia, myleosuppresion, pancreatitis, peripheral neuropathy
Hypersensitivity reaction predicted by HLA B 5701 POS
Dideoxyinosine is least toxic followed by stavudine and zidovudine
How do non-NRTIs work?
Inhibit HIV reverse transcriptase non-competitively at an allosteric site (resistance arises in weeks)
What are some adverse effects of non-NRTIs?
Drug interactions
Nightmares, headache, dizziness, rash, depression
How do integrase inhibitors work?
Incompletely prevents insertion of HIV DNA into the human DNA genome, interfering with DNA replication