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Anti-HIV - updated
Pharm Assessment 12
35
Pharmacology
Graduate
01/19/2012

Additional Pharmacology Flashcards

 


 

Cards

Term
At what CD4+ Tcell count should an Asymptomatic HIV infected person be offered treatment? When should a Symptomatic HIV infected person be treated?
Definition
Aymptomatic >200 but <350cells/uL

Symptomatic Treat at any value
Term
What are the Benefits and Risks of Deferring Anti-HIV treatment?
Definition

Benefits:

Avoid negative effects on quality of life

Avoid drug related toxicity

Preserve future drug options

Delay Drug resistance

Decrease total time on Medications

 

Risks:

Possible irreversible immune system depletion

Increased possibility of progression to AIDS

Possible increased risk of HIV transmission

Term
What are the Fusion Inhibitor Anti-HIV drugs?
Definition

Enfuvirtide

 

(Binds gp41)

Term
Which fusion inhibitor binds to gp41?
Definition

Enfuvirtide

 

Binds gp41 of the viral envelope -> prevents conformational change and impedes the fusion of the viral and host cell membranes

Term
What type of resistance can develop with Enfuvirtide?
Definition
gp41 mutations may develop when drug given at suboptimal doses as monotherapy
Term
Why does Enfuvirtide have to be administered subcutaneously?
Definition
Made up of 36 amino acid synthetic peptide
Term
What Fusion Inhibitor has an increased risk of bacterial pneumonia?
Definition
Enfuvirtide
Term
What are the Nucleoside Reverse Transcriptase Inhibitors?
Definition

Didanosine

Lamivudine

Zidovudine

 

Combinations:

Combivir (AZT+3TC)

Trizivir (AZT+3TC+Abacavir)

Term
What is the Mechanism of Action of the NRTIs?
Definition

Analogs of naturally occurring nucleosides

 

Competitive inhibitor of viral reverse transcriptase -> Once Binds -> DNA chain termination

Term
What NRTIs are analogs of pyrimidine nucleoside (T)?
Definition
Zidovudine
Term
What NRTIs are analogs of pyrimidine nucleoside (C)?
Definition
Lamivudine
Term
What NRTI is an analog of purine nucleosides (A,G)?
Definition
Didanosine
Term
What NRTI is the only one shown to reduce perinatal HIV transmission?
Definition
Zidovudine
Term
What general pharmacological properties do the NRTIs have?
Definition

Good oral absorption

Poor binding to plasma proteins

Metabolism does not rely on cytochrome P-450 system

Excreted unchanged in urine except, Zidovudine

Term
What NRTI is metabolized to glucoronide?
Definition
Zidovudine
Term
Which NRTI is acid labile? How should it be taken?
Definition

Didanosine

 

Take 1/2h before or 2h after meals

Term
What Common toxicities do the NRTIs have? What drug has a higher incidence in some?
Definition

GI distress

 

Lactic acidosis with hepatic steatosis

(higher incidence with stavudine)

 

Lipodystrophy

(higher incidence with stavudine)

Term
What NRTI can cause Bone Marrow suppression?
Definition
Zidovudine
Term
What NRTI can cause diarrhea, peripheral neuropathy, pancreatitis?
Definition
Didanosine
Term
What drugs should be avoided with Zidovudine?
Definition

Drugs that are bone marrow suppressive

 

Ganciclovir

interferon alpha

dapsone

flucytosine

vincristine

vinblastine

Term
What drugs should be avoided with Didanosine? why?
Definition

Augment neuropathy and pancreatitis

Ethambutol

isoniazid

vincristine

cis-platin

 

Increases Plasma conc 2x

Ganciclovir

 

Decreases Plasma levels:

Methadone

Term
What NRTI's plasma concentration is increased by trimethoprim-sulfamethoxazole?
Definition
Lamivudine
Term
What are the Protease Inhibitors?
Definition

Ritonavir

Saquinavir

Term
What is the most effect group of ARTs available?
Definition
Protease Inhibitors
Term
What are Protease Inhibitors effective for?
Definition

in both acutely and chronic HIV-1 infected cells

 

in monocytes and macrophages

 

(Early stages of HIV-1 replicaion cycle not affected)

Term
What is the mechanism of Action of the Protease Inhibitors?
Definition

Selective, competitive inhibitors of HIV proteases

 

Bind reversibly to protease active site

 

Prevent cleavage of polyprotein and block viral maturation

Term
What PIs have an increased plasma concentration if taken with a meal?
Definition

Increased:

Saquinavir (600%)

Ritonavir (15%)

 

Term
What PI is a potent inhibitor of CYP3A4 and can be used to increase plasma conc of other PIs?
Definition
Ritonavir
Term
Which PIs have autoinduction of metabolism?
Definition
Ritonavir
Term
Are dose adjustments needed for renal dysfunction when using PIs?
Definition
No, Renal excretion is minimal
Term
How does Ketoconazole effect PIs?
Definition
upregulates PIs (adjust dose)
Term
What drugs AUC is augmented by PIs?
Definition

Sildenafil (Viagra)

 

(PIs inhibit metabolism of Sildenafil -> increasing plasma conc.)

Term
What PIs reduce Methadones AUC?
Definition
Ritonavir
Term
What are the common adverse effects of PIs?
Definition

Hyperlipidemia (more with Ritonavir)

 

Insulin resistance and diabetes Lipodystrophy

(buffalo hump, protease paunch)

 

Elevated Liver Function tests

 

Increased Bleeding risk in hemophiliacs

 

Drug-Drug interactions

Term
What PI can cause hepatotoxicity at high doses?
Definition
Ritonavir
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