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22 Cards in this Set
- Front
- Back
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Explain the steps in how a drug must start and the b eliminated?
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the drug starts off in one compartment i.e. the gut n then absorbed and then enters the blood passing thru the certain barriers and then get eliminated by metabolic inactivation or by excretion from the body
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describe what does absorption means as well as incorporation of bioavialibity?
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absorption is the transfer of a drug to the bloodstream.
the rate and efficency depends on administration i.e. IV, oral etc. The Bioavalibity goes down when other routes BESIDES IV is being used. i.e. oral etc. |
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which one has a higher bioavilabity oral or IV?
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IV
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explain the 4 major permeation mechanisms?
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1) aqueous diffusion: bulk flow is through intercellular pores most common (except CNS).. important to realize is that across capillaris its the BLOOD flow that is limiting not the liposlution of the drug or pH gradients! i.e in the kidney.
in the CNS there are tight junctions. lipid diffusion: most important cause large barriers that serparte the compartments of the body.. movement from aquesous to lipid varies w/ pH.. based on Henderson-Hasselbach equation. special carriers: molecules like AA, glucose, peptides. Endocytosis and exocytosis |
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First-pass effect?
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fraction of the drug is metabolized in the gut wall and liver before reaching the systemic circualtion.
Note: if given IV there is no first pass effect |
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which method provides the highest bioavialiblity?
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IV highest bioavilabity
sublingual by passes intestine and liver rectal avoidance of first pass effect |
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Parenteral?
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intravenous- 100% bioavialbiity
intermuscular is faster than oral administration intradermal- i.e. ppd subcutantous: insulin |
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weak base and weak acid? explain?
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the uncharged form HA will be able to permate through the membrane while A- will not leaving an H+= weak acid
weak base: BH+ will not b ablle to penatrate but leaving a B (base) and a H+. the protanted form of a weak acid= liposoluble form (HA) the unprotonated form is the more liposoluble form (B) |
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bioequivalence?
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when two preparations of the same drug has equal concentration-time plots they are said to be bioequivalent
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bioavailability?
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based on plasma levels based on the AUC IV and AUC of oral... and thus the abosorption amount. AUC oral/AUC absorption x 100= F
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acidic drugs bind to....?
basic drugs bind to.....? |
plasma albumin
alpha1-acid gylcoprotein ** unbound durgs are pharmacologically active d |
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when sulfonamindes increases the risk of what occurs and what is being dislplaced?
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and increase of bilirubin enchephaolpathy in newborn... and displacement of unconjugated bilirbuim from albumin.
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explain the complication of lopinavir and first pass metabolism? and the soln?
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Lopinavir cannot achieve theraputic levels cause of extensive first pass metabolism.. thus applying CYP3A4 ritonaivir INHIBITOR will allow for the Lopinavir to increase therapetuic concentration.
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which transporter has limiting oral bioavaliaility of drugs lke digoxin and HIV-1 prtoetease inhibitors and what is the mechanism?
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MDR1 or P-glycoprotein... and do soo by actively transporting compounds into the intestinal lumen.
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what drug can inhbit MDR1?
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macrolide antibotics.. inhibition of MDR1 can lead to increase serum levels of drugs because it inhibtis the transport back into the lumen to be excreted.
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clarithromycin plus digoxin does what?
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decrease MDR1 transport thus there is more plasma concentration.
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Grapefruit juice inhibits?
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CYP3A4 and MDR1 in the small intestine
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explain the complication of lopinavir and first pass metabolism? and the soln?
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Lopinavir cannot achieve theraputic levels cause of extensive first pass metabolism.. thus applying CYP3A4 ritonaivir INHIBITOR will allow for the Lopinavir to increase therapetuic concentration.
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which transporter has limiting oral bioavaliaility of drugs lke digoxin and HIV-1 prtoetease inhibitors and what is the mechanism?
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MDR1 or P-glycoprotein... and do soo by actively transporting compounds into the intestinal lumen.
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what drug can inhbit MDR1?
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macrolide antibotics.. inhibition of MDR1 can lead to increase serum levels of drugs because it inhibtis the transport back into the lumen to be excreted.
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clarithromycin plus digoxin does what?
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decrease MDR1 transport thus there is more plasma concentration.
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Grapefruit juice inhibits?
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CYP3A4 and MDR1 in the small intestine
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