antivirals Flashcards
Capsid
Capsid: protein coat surrounding genetic material of a virus
- DNA polymerase:
- DNA polymerase: an enzyme which catalyzes the process of DNA
replication
- Endocytosis:
- Endocytosis: ingestion/engulfing of materials (e.g. a virus) via the
cell membrane
- Envelope:
- Envelope: outermost lipid (fatty) layer which protects genetic
material when traveling between host cells; only present on some
viruses
- Incubation period:
- Incubation period: time duration between exposure to the virus and
the appearance of symptoms
- Latency:
- Latency: the ability a pathogenic virus to lie dormant within a cell
- Neuraminidase:
- Neuraminidase: an enzyme found on the surface of influenza virus
which enables the virus to be released from the host cell
- Nucleocapsid:
- Nucleocapsid: core of a virus, made up of the genetic material and
the capsid
- Reverse transcriptase:
- Reverse transcriptase: an enzyme used to generate
complementary DNA (cDNA) from an RNA template (reverse
transcription)
- RNA polymerase:
- RNA polymerase: the enzyme which catalyzes the process of
transcription
- Transcription:
- Transcription: the synthesis of RNA from a DNA template
- Translation:
- Translation: the synthesis of protein from RNA
- Virion:
- Virion: a complete and free-living virus particle outside of its host;
the vehicle for transmission of the genome to the next host cell or
organism
What is a Virus?
* genomes?
* Viral genomes direct their own?
* metabolic machinery
* alive?
* Can infect all ?
* Reproduction rate?
* tx dif?
What is a Virus?
* “Virus” in Latin means “poison”
* Small, obligate parasites with DNA or RNA genomes
* Viral genomes direct their own replication and the synthesis of other
viral components, using host cell machinery
* No metabolic machinery of their own
* Not “alive” themselves
* Can infect all living organisms; commonly cause disease in humans
* Reproduces much faster than bacteria
* Much more difficult to treat than bacteria
Pellett PE, et al. Basics of virology. Handb Clin Neurol. 2014.
viral structures?
DNA viruses for this class
RNA viruses for this class
DNA vs RNA life cycles
Virus Life Cycle General Steps:
1. Attachment:
2. Entry:
3. Replication:
- Attachment: Polypeptide binding sites (on envelope or capsid) interact with host cell receptors
- Entry: receptor-virus complex enters host cell (e.g. endocytosis)
- Replication: utilizing host cell metabolic processes, nucleic acids and proteins are synthesized and assembled into viral particles
* Process varies (DNA vs RNA)
DNA Viruses life cycle
* Viral DNA enters?
* Host cell’s enzyme used?
* Translation?
* what is made?
* Release of?
* end resullts
- Viral DNA enters host cell nucleus
- Host cell’s RNA polymerasem catalyzes transcription into mRNA
- Translation of mRNA into virus- specific proteins: Enzymes for further synthesis of
viral DNA and Structural proteins comprising viral coat and envelope - Release of complete virions
- Via budding or host cell lysis
RNA Viruses life cycle
* mRNA production?
* Translation into?
* Assembly of and release?
* NOTE:
- Enzymes within virion synthesize
mRNA from the viral RNA template
OR viral RNA serves as its own
mRNA - Translation into enzymes
(including RNA polymerase,
structural proteins) - Assembly of and release similar to
DNA viruses - NOTE: host cell nucleus usually
NOT involved in viral replication
Retroviruses (RNA)
* Virion contains ?
* DNA copy?
* Provirus DNA is?
* Completed viruses released?
* NOTE:
Retroviruses (RNA)
* Virion contains reverse
transcriptase enzyme (RNA-
dependent DNA polymerase)
complementary DNA
* DNA copy integrated into host cell
genome (“provirus”)
* Provirus DNA is transcribed into
new viral genome RNA and mRNA
for translation into viral proteins
* Completed viruses released via
budding
* NOTE: retroviruses often replicate
without killing host cell
Common Viral Drug Targets
Herpesviruses
* genome?
* Responsible for?
* Eight Types Can Infect Humans:
- DNA viruses
- Responsible for cold sores, genital ulceration, chickenpox, shingles,
etc. - Eight Types Can Infect Humans:
- Herpes simplex viruses (HSV-1 and HSV-2)
- Varicella-zoster virus (VZV/HHV-3)
- Epstein-Barr virus (EBV/HHV-4)
- Cytomegalovirus (CMV/HHV-5)
- Herpesvirus type 6 (HBLV/HHV-6)
- Herpesvirus type 7 (HHV-7)
- Kaposi’s sarcoma herpesvirus (KSHV/HHV-8)
Herpes Simplex Viruses (HSV-1 &
HSV-2)
* *Manifestations
hsv 1 and 2 spread
Highly Contagious:
* Transmission via direct contact
* Sharing food utensils/drinks
* Oral-genital contact
hsv development cycle
hsv exposure
hsv primary infection
hsv latency
hsv reactivation
hsv triggers for reactivation
prodromal symptoms of hsv reactivation
pain, tingling, burning
hsv tx agents
hsv Therapeutic management considerations:
- Primary vs reactivated infection
- Severity
- Site of infection
- Frequency of recurrences
acyclovir preps for hsv
oral cap, tablet, suspension and ointment
acyclovir moa
Converted to acyclovir monophosphate (via thymidine kinase) and
triphosphate (via other enzymes) to target viral DNA synthesis
Monophosphate: incorporates into viral DNA = chain termination
Triphosphate: competitive inhibition and inactivation of viral DNA
polymerase
acyclovir rx for adults (recurrent and primary infections)
adjusted for?
acyclovir interactions
tizanidine
acyclovir adrs
GI upset, malaise; Local pain (topical)
valcyclovir preps
Oral: tablets (500 mg or 1000 mg)
valcyclovir moa
Prodrug which is rapidly converted to acyclovir
[See acyclovir MOA]
valcyclovir dosing (primary and recurrent infections)
adjust for?
valcyclovir interaction
tizanidine
valcyclovir Adverse Effects
GI upset, headache
maternal use of valcyclovir
Following maternal administration of valacyclovir, acyclovir is detectable in cord
blood and amniotic fluid; Pregnancy Category B
Higher than serum concentrations present in breast milk (caution)
DDIs: Acyclovir and Valacyclovir
penciclovir prep
1% external cream
penciclovir moa
penciclovir dosing
penciclovir ddi
minimal
penciclovir adr
Erythema, headache
maternal penciclovir
not used
famciclovir preps
Oral: tablets (125, 250, and 500 mg)
*Tablets contain lactose
famciclovir moa
Prodrug which is rapidly converted to active penciclovir
[See Penciclovir MOA]
famciclovir dosing (primary and recurrent infections)
adjust for?
famciclovir ddis
minimal
famiciclovir adrs
Nausea, headache
famciclovir in pregnancy
Docosanol preps
10% external cream
docosanol moa
docosanol dosing
docosanol ddi
none
docosanol adrs
well tolerated
Thymidine Kinase role and selectivity with rx
Penciclovir: Efficacy
Penciclovir: Efficacy
* Penciclovir 1% cream vs. matching
placebo cream
* 3,057 immunocompetent patients
initiated treatment
* Penciclovir: n = 1,516
* Placebo: n = 1,541
* Penciclovir recipients’ lesions healed
31% faster than placebo patients
* HR 1.31; 95% CI (1.20 to 1.42); P=
0.0001)
* Significant benefit when initiated in
both early (p = 0.001) and later (p =
0.0055) stages
* Effective at speeding healing and
pain relief by ~1 day
acyclovr suspensionexample rx
valacyclovir recurrence example rx
penciclovir example rx
famciclovir recurrence example rx
Orthomyxoviruses
* genome
* Responsible for?
* Four generates
- RNA viruses
- Responsible for causing influenza
- Four generate infect vertebrates
- Influenza A (most virulent, “seasonal flu”)
- Influenza B (“seasonal flu”)
- Influenza C (milder)
- Influenza D (infect swine, cattle, sheep – NOT humans)
Influenza A
* Divided into subtypes based on?
* Subtypes known to infect humans:
* Known to cause ?
Influenza A and B
* Cause?
* Affect who?
* transmission?
* Incubation period:
- Cause acute viral respiratory disease or “seasonal flu”
- Affect individuals of all ages worldwide
- Primarily respiratory droplet transmission person-to-person
(sneezing, coughing, etc.) - Some airborne and indirect contact transmission
- Incubation period: average ~2 days (range 1-4 days)
Influenza A and B
* Manifestations (not comprehensive):
- Fever, nonproductive cough, myalgia, malaise, chills, sore
throat, nausea, congestion, headache, fatigue - Varies based on infecting strain and severity
flu A and B drugs
- Oseltamivir (Tamiflu)
- Baloxivir marboxil (Xofluza)
Therapeutic management considerations of flu A and B:
- Treatment vs. post-exposure prophylaxis
- Severity
- Onset of symptoms (48-hour window)
Oseltamivir prep
oral ans suspension
Oseltamivir dosing
tx and prevention,adjust for?
Oseltamivir moa
Oseltamivir ddi
minimal
Oseltamivir adr
gi, headache
Oseltamivir maternal
Oseltamivir phosphate and its active metabolite oseltamivir carboxylate cross the
placenta. Use during pregnancy and breastfeeding is acceptable.
Limited excretion into breast milk
Neuraminidase Inhibitors diagrammed
Baloxavir marboxil prep
single tablet pack (40 or 80 mg)
Baloxavir marboxil moa
Baloxavir marboxil dosage
tx and prophy
Baloxavir marboxil ddi
Baloxavir marboxil adrs
gi upset
Baloxavir marboxil pregnancy
Pregnancy: No adverse events in animal reproduction studies; minimal data; not
recommended
Unknown if excreted in breast milk
endonuclease inhibitors diagrammed
oseltamavir example rx
Baloxavir marboxil example rx
Retroviruses
- RNA viruses
- Responsible for causing acquired immunodeficiency syndrome
(AIDS), T-cell leukemia - Retroviruses with implications in Dentistry
- HIV-1: Most common; higher rate of transmission, Worldwide
- HIV-2: Also causes immune suppression; less virulent, Endemic in West Africa
Human Immunodeficiency Virus
(HIV)
Oral Care challenges for the HIV Patient
Oral Complications of HIV
what is seen with low cd4 counts
Opportunistic Infections of HIV
cd4 levels for prophy, preffered agents
HIV Transmission
- Anal or vaginal intercourse
- Oral sexual activity
- Exposure to infected blood
- Sharing of needles or syringes (injecting drugs,
tattooing, etc) - Accidental percutaneous injury
- Pregnancy, childbirth, or breastfeeding
HIV Post-Exposure Prophylaxis (PEP)
timeframe
HIV PEP regimens
HIV PrEP
pre tx testing
Preventative strategy to prevent transmission of HIV for those who are at high risk but are currently HIV negative
Pre-treatment evaluation and testing:
* HIV, HBV, STI testing
* Renal function, osteoporosis, lipid testing
HIV PrEP regimens
- Tenofovir disoproxil fumarate-emtricitabine
- Tenofovir alafenamide-emtricitabine
Reduction of HIV Transmission strategies
undetectable HIV means?
untransmissable
HIV Life Cycle steps
- Binding
- Fusion
- Reverse Transcription
- Integration
- Replication
- Assembly
- Budding
binding anf fusion of hiv
what rx’s stop these stages
reverse transcription of hiv
integration hiv
replication, assembly, and budding of hiv
inhibitory rx?
Antiretroviral Therapy
The routine use of a combination of HIV medication classes to?
* Recommended for?
*cure?
* Potential for?
The routine use of a combination of HIV medication classes to
treat or prevent HIV
* Recommended for all patients with HIV, regardless of CD4
count
* NOT a cure
* Potential for resistance; adherence is KEY
goals of ART
- Reduce morbidity and mortality associated with HIV
- Restore and preserve immunologic function
- Suppress plasma HIV viral load
- Prevent HIV transmission
HIV Drug Classes
* Nucleoside Reverse Transcriptase Inhibitors (NRTI)
* Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI)
* Protease Inhibitors (PI)
* Integrase Strand Transfer Inhibitors (INSTI)
* Fusion Inhibitors
* CCR5 Antagonists
* Attachment Inhibitors
* Post-Attachment Inhibitors
* Capsid Inhibitors
NRTIs and NNRTIs moa diagrammed
NRTIs
* Nucleoside reverse Transcriptase Inhibitors names
- Abacavir (Ziagen)
- Abacavir-Lamivudine (Epzicom)
* Abacavir-Lamivudine-Zidovudine (Trizivir) - Didanosine (Videx)
- Emtricitabine (Emtriva)
- Lamivudine (Epivir)
- Stavudine (Zerit)
* Tenofovir alafenamide-Emtricitabine (Descovy) - Tenofovir disoproxil fumarate (Viread)
* Tenofvoir disoproxil fumarate-Emtricitabine (Truvada) - Zidovudine (Retrovir)
- Zidovudine-Lamivudine (Combivir)
NRTI moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA( cDNA
Abacavir-Lamivudine-Zidovudine (Trizivir) moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA( cDNA
Tenofovir alafenamide-Emtricitabine (Descovy) moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA( cDNA
Tenofvoir disoproxil fumarate-Emtricitabine (Truvada) moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA( cDNA)
NRTI adrs
common and serious adrs
- Common: N/V/D, upset stomach, headache
- Serious: bone marrow suppression (and associated increased risk of bleeding or oral ulcers), peripheral neuropathy, pancreatitis, lipoatrophy, hepatic steatosis, lactic acidosis
NRTI contraindications
- Abacavir and moderate or severe hepatic insufficiency
NRTI ddi
minimal
* Tenofovir products and high-dose or multiple NSAIDs May enhance nephrotoxic effects of tenofovir
* Category D: Consider Therapy Modification
NNRTIs
* Non-nucleoside reverse transcriptase inhibitors names
- Doravirine (Pifeltro)
* Efavirenz (Sustiva) - Etravirine (Intelence)
- Nevirapine (Viramune)
* Rilpivirine (Edurant)
NNRTIs moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA (cDNA)
* Binding occurs in a pocket further away from active site
Efavirenz (Sustiva) moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA (cDNA)
* Binding occurs in a pocket further away from active site
Rilpivirine (Edurant) moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA (cDNA)
* Binding occurs in a pocket further away from active site
nnrtis adr
common ones, sedation? serious adr?
Rilpivirine must be administered with?
Rilpivirine must be administered with a full meal to increase absorption
(better absorbed with acids)
Rilpivirine*
PLUS ddi
Efavirenz or Etravirine ddi
Protease Inhibitors (PIs) diagrammed
Protease Inhibitors (PIs)
* MOA:
- MOA: block protease enzyme to prevent new (immature) HIV from
becoming a mature virus that can infect other CD4 cells
Protease Inhibitors and P450
- CYP3A4 substrates
- Often “boosted” by pharmacokinetic enhancers
protease inhibitors adrs
oral adverse effects of :
* Atazanavir, Ritonavir, Fosamprenavir
- Fosamprenavir - Perioral numbness (lips), taste changes
- Atazanavir - Dental (tooth) pain, taste changes
- Ritonavir - Taste changes
Protease Inhibitors
* Examples:
-vir suffix
* Atazanavir (Reyataz)
* Atazanavir-Cobicistat (Evotaz)
* Darunavir (Prezista)
* Darunavir-Cobicistat (Prezcobix)
* Fosamprenavir (Lexiva)
* Indinavir (Crixivan)
* Lopinavir-Ritonavir (Kaletra)
* Nelfinavir (Viracept)
* Saquinavir (Invirase)
* Tipranavir (Aptivus)
Atazanavir (Reyataz) moa
block protease enzyme to prevent new (immature) HIV from
becoming a mature virus that can infect other CD4 cells
Atazanavir-Cobicistat (Evotaz) moa
block protease enzyme to prevent new (immature) HIV from
becoming a mature virus that can infect other CD4 cells
Darunavir (Prezista) moa
block protease enzyme to prevent new (immature) HIV from
becoming a mature virus that can infect other CD4 cells
Darunavir-Cobicistat (Prezcobix) moa
block protease enzyme to prevent new (immature) HIV from
becoming a mature virus that can infect other CD4 cells
Fosamprenavir (Lexiva) moa
block protease enzyme to prevent new (immature) HIV from
becoming a mature virus that can infect other CD4 cells
Darunavir ddi with:
Atazanavir ddi with:
Fosamprenavir ddi with:
INSTIs moa diagrammed
Integrase stand transfer inhibitors
INSTIs moa
block integrase enzyme, preventing insertion of HIV viral DNA into the
DNA of the host CD4 cell, thus preventing replication
INSTIs general adrs
- Generally well tolerated
- Increased weight gain, insomnia, dizziness
INSTIs adrs for dentistry
- Osteopenia/osteoporosis
- Xerostomia (dry mouth)
- Oral ulcers, mucosal irritation
- Altered taste
- Increased risk of bleeding
INSTIs: DDIs
* Raltegravir PLUS:
- Proton pump inhibitors= may increase concentrations of raltegravir
- Category B: No Action Needed
INSTIs
* Examples:
* suffix?
-gravir suffix
* * Cabotegravir (Apretude)
* Dolutegravir (Tivicay)
* Raltegravir (Isentress)
* Elvitegravir (within combination products)
* Bictegravir (within combination products)
Dolutegravir (Tivicay) moa
block integrase enzyme, preventing insertion of HIV viral DNA into the
DNA of the host CD4 cell, thus preventing replication
Bictegravir (within combination products) moa
block integrase enzyme, preventing insertion of HIV viral DNA into the
DNA of the host CD4 cell, thus preventing replication
backbone hiv therapy
Other Drug Classes for HIV
- CCR5 Antagonists
- Attachment Inhibitors
- Post-Attachment Inhibitors
- Capsid Inhibitors
Pharmacokinetic Enhancers moa
Pharmacokinetic Enhancers general adrs
gi upset
Pharmacokinetic Enhancers dentistry related adrs
which specific PK enhancer?
- Ritonavir: Metallic or bitter taste, oral ulcers or inflammation, perioral numbness/tingling, increased bleeding risk (if DDI with anticoagulants)
- Dry mouth
Pharmacokinetic Enhancers examples
- Ritonavir (Norvir)
- Cobicistat (Tybost)
Ritonavir (Norvir) moa
block CYP3A4, increase rx concentration (decreases amoutn rx used= lower toxiciity)
- Cobicistat (Tybost) moa
block CYP3A4, increase rx concentration (decreases amoutn rx used= lower toxiciity)
Pharmacokinetic Enhancers diagrammed
Ritonavir ddis with:
Cobicistat ddis with:
most common signle tab regimens for HIV
Bictegravir-TAF-Emtricitabine MOA’s
Bictegravir: INSTI
TAF-Emtricitabine: NRTI
Dolutegravir-Abacavir-Lamivudine moa’s
Dolutegravir- INSTI
Abacavir- NRTI
Lamivudine- NRTI
Dolutegravir-Lamivudine moa’s
Dolutegravir- INSTI
Lamivudine- NRTI
hsv tx agents
- Oseltamivir (Tamiflu)
- Baloxivir marboxil (Xofluza)
flu A and B drugs
- Abacavir (Ziagen)
- Abacavir-Lamivudine (Epzicom)
* Abacavir-Lamivudine-Zidovudine (Trizivir) - Didanosine (Videx)
- Emtricitabine (Emtriva)
- Lamivudine (Epivir)
- Stavudine (Zerit)
* Tenofovir alafenamide-Emtricitabine (Descovy) - Tenofovir disoproxil fumarate (Viread)
* Tenofvoir disoproxil fumarate-Emtricitabine (Truvada) - Zidovudine (Retrovir)
- Zidovudine-Lamivudine (Combivir)
NRTIs
* Nucleoside reverse Transcriptase Inhibitors names
- Doravirine (Pifeltro)
* Efavirenz (Sustiva) - Etravirine (Intelence)
- Nevirapine (Viramune)
* Rilpivirine (Edurant)
NNRTIs
* Non-nucleoside reverse transcriptase inhibitors names
* Atazanavir (Reyataz)
* Atazanavir-Cobicistat (Evotaz)
* Darunavir (Prezista)
* Darunavir-Cobicistat (Prezcobix)
* Fosamprenavir (Lexiva)
* Indinavir (Crixivan)
* Lopinavir-Ritonavir (Kaletra)
* Nelfinavir (Viracept)
* Saquinavir (Invirase)
* Tipranavir (Aptivus)
Protease Inhibitors
* Examples:
- Cabotegravir (Apretude)
* Dolutegravir (Tivicay) - Raltegravir (Isentress)
- Elvitegravir (within combination products)
- Bictegravir (within combination products)
INSTIs
* Examples:
- Ritonavir (Norvir)
- Cobicistat (Tybost)
Pharmacokinetic Enhancers examples
what can these formulations be used for?
HIV PEP regimens
mechanism of what rx?
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA( cDNA
NRTI moa
block and prevent reverse transcriptase enzyme from accurately
copying its RNA into complementary DNA (cDNA)
* Binding occurs in a pocket further away from active site
NNRTIs moa
- MOA: block protease enzyme to prevent new (immature) HIV from
becoming a mature virus that can infect other CD4 cells
Protease Inhibitors (PIs)
* MOA:
block integrase enzyme, preventing insertion of HIV viral DNA into the
DNA of the host CD4 cell, thus preventing replication
Integrase stand transfer inhibitors
INSTIs moa
Pharmacokinetic Enhancers moa
what HIV rx is both a PI and a PK enhancer?
ritonavir