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68 Cards in this Set
- Front
- Back
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Single dose kinetics
If you increase ka what happens to Latency: Time to peak: Peak size: Duration: |
Latency: shorter
Time to peak:faster Peak size:larger Duration:shorter |
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Single dose kinetics
If you increase dose what happens to Latency: Time to peak: Peak size: Duration: |
Latency: shorter
Time to peak:same Peak size:larger Duration:longer |
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Single dose kinetics
If you increase half life what happens to Latency: Time to peak: Peak size: Duration: |
Latency: same or shorter
Time to peak:slower Peak size:larger Duration:longer |
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Single dose kinetics
If you decrease ke what happens to Latency: Time to peak: Peak size: Duration: |
Latency: same or shorter
Time to peak:slower Peak size:larger Duration:longer |
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__________ route of drug adminstration is not via the alimentary canal
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Parenteral
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ways to manipulate the perfusion rate for absorption from subcutaneous, intramuscular, and intradermal injections
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Decrease rate: lower skin temp, immobilization, tournequet, vasoconstrictors, insoluble drug, hypovolemic shock
Increase: massage, exercise, heat, vasodilators, expand surface area, selection of injection site |
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_____________ is a drug administration via the alimentary canal
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Enteral
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Passive Diffusion:
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This is a first order process, dependent on the lipid solubility of a drug, and is non-saturable
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Carrier- mediated transport:
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Drugs bound to a carrier are transported across a membrane. This process is saturable, and competition can occur
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Drug binding to serum proteins 5 important points
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1.absorption rate is generally increased
2.distribution is usually more rapid 3.storage depot effect 4.drug competition for protein binding sites can have important therapeutic implications 5.the elimination rate is generally decreased, but depends on the relative dissociation rate constant |
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___________ compartment comprised of tissues to which drugs rapidly distribute, and _________ compartment comprised of tissues to which drugs distribute very slowly
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central
peripheral |
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In CNS drug distribution ________ can alter the drug permeability barrier, while elimination of drugs is primarily by ___________
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infection
back diffusion |
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Why should drugs be restricted during pregnancy?
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1.Compounds less than 1000 daltons can diffuse across the placenta
2.lipophilic drugs readily cross the placenta membrane 3.immature liver and kidney function in fetus limits drug metabolism and elimination 4. first trimester and teratogenesis |
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aliphatic hydroxylation
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an oxidative phase one reaction, involves the microsomal enzymes of the liver, is non-synthetic reaction, and generally serves to produce a more polar compound
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hydroxylation of aromatic rings
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an oxidative phase one reaction, involves the microsomal enzymes of the liver, is non-synthetic reaction, and generally serves to produce a more polar compound
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N-dealkylation
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(rmoval of a methyl group)an oxidative phase one reaction, involves the microsomal enzymes of the liver, is non-synthetic reaction, and generally serves to produce a more polar compound
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O-dealkylation
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(ether cleavage)an oxidative phase one reaction, involves the microsomal enzymes of the liver, is non-synthetic reaction, and generally serves to produce a more polar compound
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oxidative deamination
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an oxidative phase one reaction, involves the microsomal enzymes of the liver, is non-synthetic reaction, and generally serves to produce a more polar compound
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oxidative reactions overall reaction
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NADPH + O2 + drug = NADP + H2O + oxidized drug
consists the following steps: 1.NADPH + A + H ~ AH2 + NADP 2.AH2 + O2 ~ active oxygen 3.Active oxygen + drug ~ oxidized drug + A H2O |
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3 types of nonsynthetic reactions (phase I)
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1.oxidative
2.Reductions 3.hydrolyses |
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Glucuronide synthesis
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Synthetic (phase II) reaction. UDPGA (uridine diphosphate-glucuronic acid) is produced in the liver. UDPGA can donate glucuronic acid to various acceptors, in reactions mediated by transferases found in the liver and other tissues
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Glycine conjugation
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A synthetic (phase II) reaction. Is characteristic for certain aromatic acids. Depends on the availability of coenzyme A , glycine, and glycine N acylase
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Methylation
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synthetic phase II reaction. Norepinephrine and epinephrine are metabolized in part by a process of O methylation, whereas nicotinic acid is metabolized to N methylnicotinic acid, an example of N methylation. The source of methyl groups for drug methylations is S adenosylmethionine
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Acetylation
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synthetic (phase II) reaction. The acetylating ability of various patients may vary considerably. In the case of isonicotinic acid hydrazide a low degree of acetylation shows some correlation with incidence of toxic reactions such as peripheral neuritis
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Ethereal sulfate synthesis
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Synthetic (phase II) reaction. Phenolic compounds may be excreted in part as ethereal sulfates
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nonsynthetic reactions
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phase I reactions. first phase of drug metabolism often involves the addition of a functionally reactive group. Uses the liver microsome P450 system. Oxidation reactions, reduction reactions, and hydrolysis reactions.
Phase I reactions are not required where a drug already contains a reactive group |
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Conjugation reactions
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(syntheic reactions) Phase II reactions.
1.Glucuronidation 2.N methylation 3.S methylation 4.Acetylation 5.Amino acid 6.sulfate formation 7.Mercapturic acid formation |
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main sites of biotransformation
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1.The liver is the major site. The microsomal enzymes are found in the smooth ER, are nonspecific and can metabolize a variety of structures. A first pass effect can be observed where the rate is rapid
2.GI tract 3.Plasma 4.lung |
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consequences of biotransformation on elimination
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1.formation of polar compounds and drug elimination
2.Methylation and acetylation do not favor elimination 3.enzyme kinetics are followed 4.competition for biotransformation 5.Induction of microsomal enzymes and cross-tolerance |
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consequences of biotransformation on activity
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1. generally but not always leads to deactivation
2.inactive drug can be converted to active drug |
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Drug elimination
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is the sum of the processes that operate to decrease the active drug concentration, including biotransformation and excretion
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methods of elimination
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1.redistribution in tissues
2. renal excretion 3.ion trapping 4.biliary excretion |
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renal excretion
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the most important elimination route of the parent drug or its water soluble metabolite. Changes in GFR rates may alter elimination. Active secretion at the proximal tubules for cations and anions is saturable and subject to competition between members of the same class of drugs. Passive secretion of lipid-soluble drugs. There is drug reabsorption. Renal drug clearance is the elimination of drug from a certain volume of plasma per minute
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renal clearance =
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renal clearance = (excretion rate in amount per min)/(drug plasma concentration in amount per ml)
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urinary excretion can be used to study ___________
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bioavailability
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ion trapping and renal elimination
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1.weak bases are eliminated faster in acidic urine
2.weak acids are eliminated faster in alkaline urine 3.drug duration can be altered by altering urine pH |
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biliary excretion
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excretion of drug into bile- enterohepatic cycle
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Vd=
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apparent volume of distribution
Vd = D/C (total drug in body)/(plasma drug concentration) |
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Er=
ke= |
Er=elimination rate
ke=elination rate constant Er is dependent on drug concentration, ke is not |
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zero order elimination rate
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A constant amount of drug is eliminated per unit of time, and the elimination rate is independent of drug concentration. This can occur when an elimination process is saturated
Er=ke |
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first order elimination rate
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the elimination rate is dependent on the concentration of drug at any given moment
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For any drug, at one half life, _____% has been eliminated. At two half-lives, _______% has been eliminated. At 3.3 half-lives _____% of the drug has been eliminated
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50
75 90 |
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clearance
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the volume of plasma cleared of drug per unit time by all elimination processes
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iv dose kinetics from a single dose
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curve is triphasic: a rapid peak, a rapid decline phase due to redistribution from the central to the peripheral compartment, and a slow elimination phase. The half life is found from the latter phase
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s.c. or i.m. dose kinetics from a single dose
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the drug takes a finite time to reach the circulation. The blood levels of drug continues to rise as long as the absorption rate is faster than the elimination rate (not rate constant). In general, the entire dose will reach the circulation
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The administration of drug at intervals shorter than about ___ elimination half-times will result in drug accumulation
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4
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Steady state kinetics
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the administration of drug at intervals shorter than about 4 elimination half-lives will result in drug accumulation. The drug accumulation will continue until the rate of absorption equals the rate of elimination, at which time an equilibrium plateau will be reached
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time course of drug loss in a body =
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t= (half-life)/(ln2) x ln(current amount of drug/amount of drug wanted) or
(amount of drug wanted) = [current amount of drug in body][e^(-ke t)] |
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competive antagonism
effect of competion on 1.position of LDR 2.LDR slope 3.Δmax 4.apparent Kd 5.antagonist binding |
1.position of LDR: shift to the right
2.LDR slope: no change 3.Δmax: no change 4.apparent Kd:increased 5.antagonsist binding: reversible 5.antagonist binding |
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non competitive antogonism effect on
1.position of LDR 2.LDR slope 3.Δmax 4.apparent Kd 5.antagonist binding |
1.position of LDR: no change
2.LDR slope:decreased 3.Δmax:decreased 4.apparent Kd:no change 5.antagonist binding:reversible or irreversible |
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Steady state oral =
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Css= [(Dm)(F)(half life)]/[(dose interaval)(V)(ln2)]
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plasma concenration between oral doses=
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C/Css= e^[(-ln2 T)/(half life)]
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volume of distribution=
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V2 = [(C1)(V1)/(C2)]
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steady state i.v. infusion=
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Css= [(ka)(half life)]/[(ln2)(V)
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loading dose=
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Dl= [(Css)(V)]/[F]
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theraputic ratio=
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TD50/ED50= to the number times greater than the ED50 you can give before toxicity is reached
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certain safety factor=
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TD1/ED99
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equlibrium constant of disassocition =
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Kd=k2/k1 where k1= constant to form drug receptor complex and k2=constant for drug receptor complex to dissasoate
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fraction of response =
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y= Δ/Δmax = D/(D + Kd) when response curve is directly proportional to recptor occupancey Kd=ED50
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what is the level efficacy for
1.agonists 2.partial agonists 3.antaginists |
1.agonists:high
2.partial agonists:intermediate 3.antaginists:none |
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how many L are in a gallon
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3.8L/gal
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1% solution = howmany mg/ml
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10mg/ml
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how many ng in a kg
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1 x 10^12ng/kg so ng/kg= ppt
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1000 grams =
0.001 grams = 0.000001grams = 10^-9 grams = 10^-12 grams = |
1000 grams = kilogram (kg)
0.001 grams = milligram (mg) 0.000001grams = microgram (mcg) 10^-9 grams = Nanogram 10^-12 grams = Picogram |
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1000 cubic centimeters =
1.0 cubic centimeters = 0.01 cubic centimeters = |
1000 cubic centimeters = liter (L)
1.0 cubic centimeters = milliliter (mL, cc) 0.01 cubic centimeters = microliter |
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Percentage Solutions
Percent weight in volume (w/v) = Percent weight in weight (w/w) = Percent volume in volume (v/v) = |
Percentage Solutions
Percent weight in volume (w/v) = number of grams of a constituent in 100 milliliters of solution. Percent weight in weight (w/w) = number of grams of a constituent in 100 grams of solution. Percent volume in volume (v/v) = number of milliliters of a constituent in 100 milliliters of solution. |
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1 PPM = 1mg/? volume
1 PPB = 1mcg/? volume 1 PPM = 1mcg/? volume 1 PPB = 1 nanogram/? volume 1 PPM = ?% 1 PPB = ?% |
1 PPM = 1 mg/liter
1 PPB = 1 mcg/liter 1 PPM = 1 microgram/mL 1 PPB = 1 nanogram/mL 1 PPM = 0.0001% 1 PPB = 0.0000001% |
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1 molar solution =
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mw/L
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