Shared Flashcard Set

Details

Antiviral Chemotherapy
antiviral chemo
35
Accounting
Pre-School
09/29/2014

Additional Accounting Flashcards

 


 

Cards

Term
Gamma globulin
Definition
Contains antibodies against cell surface antigen - it can modify infection with viruses such as measles
Term
Amantadine and Rimantadine MOA
Definition

Inhibit viral uncoating by blocking M2 proton channel in the viral envelope

Normally, acidification allows release of ribosomal nuclear particles and dissemination of virus because acidity triggers membrane fusion

 

Amantadine and Rimantadine only effective against influenza A 

Term
Clinical Use of Amantadine and Rimantadine - how quicly do they alleviate sx?
Definition

Do not prevent formation of antibodies when flu vaccine is given

Amantadine (Symmetrel)

Can alleviate symptoms if given within the first 48 hours and can also be used prophylactically

 

 

Term
Pharmacokinetics of Amantadine and Rimantadine
Definition

Oral administration and rapidly absorbed from GI tract

Amantadine is not metabolized and is excreted straight to urine, so might need doseage adjustments; in contrast, rimantadine will only need dose reductions when creatinine levels are really too low 

Term
Amantadine and Rimantadine Adverse Effects
Definition

Amantadine readily crosses blood brain barrier - known to cause release of dopamine from CNS (initial therapy for Parkinson's Disease)

Rimantadine has lower risk of CNS adverse effects

 

Both drugs have atropine like effects and can cause livedo reticularis; more serious side effects if given with anticholinergics


SE: anorexia, nausea, peripheral edema, minor CNS effects like nervousness and anxiety

Term
Zanamivir (Relenza) and Oseltamivir (Tamiflu) MOA
Definition
Inhibition of NA allows viruses to aggregate and reduce viral spread
Term
Zanamivir (Relenza) and Oseltamivir phosphate (Tamiflu) Clinical use
Definition

Active against both influenza A & B

Work best when administered early - within 48 hours, can improve symptoms by 1 day

For Zanamivir, administration within 30 hours improves symptoms by 3 days

For both drugs, reduction in influenza related complications and both can be used prophylactically 

 

Term
Drug of choice for bird flu
Definition
Oseltamivir 'Resistance is occuring in certain areas of the world with bird flu, but these strains are also less virulent
Term
Pharmacokineics of Oseltamivir phosphate and Zanamivir
Definition

Zanamivir has poor oral bioavailability; comes as a dry powder which is inhaled

90% of the absorbed material is excreted in urine

 

Oseltamivir is an ethy ester prodrug that is well absorbed from GI tract - will be de-esterified in liver and bioavailability will be 80% - excreted unchanged in the urine 

Term
Oseltamivir and Zanamivir (nasal) Adverse effects
Definition

Nausea/vomiting/headache in 15% of the patients for both

 

Zanamivir can also cause bronchospasm in asthamtics 

Term
Zovirax
Definition

Acyclovir 

MOA: phosphorylated vy viral thymidine kinase, and then cellular kinases (host) phosphorylate 2 more times; inhibit DNA polymerase and will bind to DNA to terminate chain elongation

 

Resistant strains are primarily due to altered viral thymidine kinase 

Term
List Clinical uses of Acyclovir (Zovirax)
Definition
Keratitis due to herpes, Encephalitis, primary and recurrent genetic herpes, mucocutaneous infections, varicella-zoster
Term
Keratitis due to Herpes
Definition

Oral acyclovir is effective, especially if patient has sensitivity

Trifulridine may be used topically, but would have unacceptable toxicity if used systemically

Ganciclovir may also be used topically

Term
Encephalitis
Definition
Many causes of encephalitis, so acyclovir should not be used without biopsy; use it right after biopsy and discontinue if it is negative for herpes
Term
Primary and Recurrent Genital Herpes
Definition

Herpes Simplex Type 2 is most common

Topical therapy is not effective for recurrent herpes

Oral therapy is good at preventing recurrence up to one year, but protective effect disappears when drug does 

Term
Mucocutaneous Infections
Definition

Intravenous acyclovir is used in mucocutaneous infections in the immunocompromised patient

IV!

Term
Pharmacokinetics of Acyclovir (Zovirax)
Definition

The drug is administered intravenously, topically, and orally; minimal systemic absorption after topical administration

Bioavailability is only 15-30% when given orally; but some of the analogues have greater bioavailability 

Widely distributed in tissue; acyclovir is eliminated by glomerular filtration and tubular secretion; metabolized by small extent 

Term
Adverse Effects of Acyclovir
Definition

1% incidence of encephalopathy, lethargy, confusion, tremor, coma, some nephrotoxicity due to crystaluria 

 

Renal insufficiency with IV dose 

Term
Ganciclovir (cytovene) MOA
Definition

Very similar to acyclovir (zovirax) except that it has additionaly hydroxymethyl group - 100x more active against cytomegalovirus retinitis 

 

Clinical use: combined use of ganciclovir and anti-CMV antibody has good effects against pneumonia caused by CMV in kidney transplant patients 

 

Significant improvement in survival rate 

Term
Pharmacokinetics of Ganciclovir (cytovene)
Definition

Oral bioavailability is extremely low; oral route is used for maintenance route

IV used for acute treatment

 

Prodrug valganciclovir can be used orally; also used as an ocular implant 

Term
Adverse Effects of Ganciclovir (cytovene)
Definition

Most common side effect is bone marrow suppression; there are also CNS effects in 5-15% of patients

 

Because of its toxicity, the drug is only used to treat cytomegalovirus infection 

Less specific for DNA polymerase than acyclovir, so can be more toxic 

 

Consider administering with Colony stimulating factor 

Term
Foscarnet
Definition

Alternative for cytomegalovirus retinitis

Acyclovir resistant HSV and VSV

Not a nucleoside analogue, IV generally 

Phosphonate derivative - inhibits DNA polymerase and reverse transcriptase by interacting with pyrophosphate binding site

More expensive and generally less well tolerated than ganciclovir (cytovene) because of large volumes of liquid that need to be infused 

Most prominent side effect: reduced renal function 

Term
Cidofovir
Definition

Considered a nucleotide analogue because it mimics deoxycytidine monophosphate

Doesn't require viral kinases for phosphorylation 

May also be used against herpes infections resistant to acyclovir 

Nephrotoxicity is major toxicity - must be administered by IV with probenicid - probenicid prolongs half life and prevents kidney toxicity

 

Also will cause neutropenia 

 

IV Only

Term
Ribavarin (Virazole) MOA
Definition

Inhibits RNA polymerase by competing with both GTP and ATP

Depletes virally infected cell of GTP by inhibition inosine monophosphate dehydrogenase

Inhibits N7 methyl transferase; blocks capping of mRNA

Because of multiple mechanisms of action, development of resistant strains is less likely

 

Term
Ribavarin Clinical Use
Definition

Active in tissue culture against 85% viruses studied, yet drug isn't toxic to cells

Used against influenza A&B, also RSV

Used incombination with IFN in hep C

Term
Ribavarin adverse effects
Definition

Used as an aerosol to treat RSV and can cause upper airway irritation 

Used orally with IFN in hep C and can cause hemolytic anemia

Also teratogenic 

Term
Fomivirsen
Definition

new drug for CMV retinitis

anti-sense mRNA for a protein necessary for viral replication

Must be injected intravitreally

Side effects is local irritation

Term
IFNs MOA
Definition

Synthesis is induced by viruses

Viral genes --> derepression of host cell genes --> rapid production of IFN --> binds nearby cells after being released into EC space --> induces protein kinase that phosphorylates and inactivates an initiation factor thereby inhibiting viral protein synthesis 

Additionally, cellular endonuclease is activated that degrades viral mRNA

Finally, phosphodiesterase is activated and degrades the terminal nucleotides of tRNA, also inhibiting peptide elongation 

Term
IFN administration and use
Definition

Because it's a peptide, it's administered subQ or intramuscularily

Chronic hep c- combo of interferon with ribavarin is much more effective than interferonn alone

after 48 weeks of treatment, the rate of relapse is decreased with the combination 

Term
SE of IFN of Ribovarin
Definition

neutropenia resulting in flu like symptoms: fever, chills, fatigue


Ribovarin will cause a hemolytic anemia

Term
Other indications of IFN
Definition

hairy cell leukemia, AIDS related Kaposi's sarcoma, and genital warts (condyloma acuminatum) 

 

IFN, if given early, can prevent dissemination of herpes zoster in cancer patients 

 

Topical administration in combo with other viral agents is effective in herpes keratoconjuctivitis 

Term
Ganciclovir Clinical Use
Definition

CMV retinitis, colitis, esophagitis

 

CMV prophylaxis in HIV patients 

Term
Trifluridine
Definition

Used topically in HSV ocular infections

Nucleoside analogue; phosphorylated form inhibits DNA polymerase

SE: local irritation

Effective against acyclovir resistant strains; too toxic for systemic useage

Term
When is ribavarin PO or inhaled? IV?
Definition

Inhaled in RSV in children, and oral in combination with IFN for hep C

Aerosol has also been used for influenza

IV can be used for Lassa fever

Term
Ribovarin in combination with IFN
Definition

Can cause myelosuppresion

 

Ribovarin is contraindicated in pregnancy

 

When used as aerosol, also careful monitoring for respiratory function is needed 

Supporting users have an ad free experience!