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pharmacy test 1
GNS
Question | Answer |
---|---|
Pharmacology | The total knowledge of drugs ( What the drug does to the body) |
Clinical pharmacology | Study of the effect of drugs in humans |
Drug administration and membrane transport | Getting it in |
Pharmacokinetics | Getting it there |
Pharmacology | The total knowledge of drugs ( What the drug does to the body) |
Clinical pharmacology | Study of the effect of drugs in humans |
Drug administration and membrane transport | Getting it in |
Pharmacology | The total knowledge of drugs ( What the drug does to the body) |
Clinical pharmacology | Study of the effect of drugs in humans |
Drug administration and membrane transport | Getting it in |
Pharmacology | The total knowledge of drugs ( What the drug does to the body) |
Pharmacokinetics | Getting it there |
Pharmacokinetics | Getting it there |
Dosing kinetics | Keeping it there |
Clinical pharmacology | Study of the effect of drugs in humans |
Clinical pharmacology: | The study of the effect of drugs in man (as compared to animal or comparative pharmacology). (The emphasis is on the drug and its uses.) |
Drug administration and membrane transport | Getting it in |
Pharmacodynamics | Action! |
Pharmacokinetics | Getting it there |
Pharmacodynamics | Action! |
Dosing kinetics | Keeping it there |
Excretion/elimination | Taking out the trash |
Pharmacodynamics | Action! |
Clinical pharmacology: | The study of the effect of drugs in man (as compared to animal or comparative pharmacology). (The emphasis is on the drug and its uses.) |
Biotransformation | Bagging up the trash |
. Pharmacotherapeutis | deals with use of drugs in prevention & treatment of disease, usually to alleviate symptoms or, sometimes, to alter the course of the disease. The emphasis is on the disease and the treatment thereof. |
Excretion/elimination | Taking out the trash |
Clinical pharmacology: | The study of the effect of drugs in man (as compared to animal or comparative pharmacology). (The emphasis is on the drug and its uses.) |
Clinical pharmacology: | The study of the effect of drugs in man (as compared to animal or comparative pharmacology). (The emphasis is on the drug and its uses.) |
. Pharmacotherapeutis | deals with use of drugs in prevention & treatment of disease, usually to alleviate symptoms or, sometimes, to alter the course of the disease. The emphasis is on the disease and the treatment thereof. |
. Pharmacotherapeutis | deals with use of drugs in prevention & treatment of disease, usually to alleviate symptoms or, sometimes, to alter the course of the disease. The emphasis is on the disease and the treatment thereof. |
Chemotherapeutic agents: | are drugs with minimal effects in man but destroy or eliminate pathogenic cells or organisms (anticancer drugs; anti-infectives). |
The relative toxicity of a drug is expressed as___________ ( Most commonly in pharmacology this is the ratio of the dose capable of killing 50% of animals (LD50) over that required to achieve a beneficial effect in 50% of the animals (ED50). | the therapeutic index In clinical terms, a drug that has a “small therapeutic index” has little difference between the therapeutic dose and the dose that causes toxicity (eg, digoxin). |
Toxicology: | deals with adverse effects of drugs. |
Tolerance | Pharmacodynamic tolerance, Metabolic tolerance |
The relative toxicity of a drug is expressed as___________ ( Most commonly in pharmacology this is the ratio of the dose capable of killing 50% of animals (LD50) over that required to achieve a beneficial effect in 50% of the animals (ED50). | the therapeutic index In clinical terms, a drug that has a “small therapeutic index” has little difference between the therapeutic dose and the dose that causes toxicity (eg, digoxin). |
Tolerance | Pharmacodynamic tolerance, Metabolic tolerance |
Tolerance | Pharmacodynamic tolerance, Metabolic tolerance |
Pharmacodynamic tolerance CROSS TOLERANCE may develop between drugs within a class (e.g., opioids) or between drugs of different classes that produce similar pharmacologic effects (e.g., alcohol & inhaled anesthetics). | is hyporeactivity that occurs from chronic exposure to a drug (such as an opioid or alcohol). When tolerance develops, usually increasing doses are needed to provide a therapeutic effect. This is attributed to neuronal adaptation or cellular tolerance. |
Pharmacodynamic tolerance CROSS TOLERANCE may develop between drugs within a class (e.g., opioids) or between drugs of different classes that produce similar pharmacologic effects (e.g., alcohol & inhaled anesthetics). | is hyporeactivity that occurs from chronic exposure to a drug (such as an opioid or alcohol). When tolerance develops, usually increasing doses are needed to provide a therapeutic effect. This is attributed to neuronal adaptation or cellular tolerance. |
Metabolic tolerance | is defined as decreased response to a dose of a drug which develops because of an increase in rate of elimination of the drug (enzyme induction is an example). The opposite can also occur, that is, enzyme inhibition. |
Metabolic tolerance | is defined as decreased response to a dose of a drug which develops because of an increase in rate of elimination of the drug (enzyme induction is an example). The opposite can also occur, that is, enzyme inhibition. |
Pharmacology | The total knowledge of drugs ( What the drug does to the body) |
Clinical pharmacology | Study of the effect of drugs in humans |
Drug administration and membrane transport | Getting it in |
Pharmacokinetics | Getting it there |
Dosing kinetics | Keeping it there |
Pharmacodynamics | Action! |
Biotransformation | Bagging up the trash |
Excretion/elimination | Taking out the trash |
Clinical pharmacology: | The study of the effect of drugs in man (as compared to animal or comparative pharmacology). (The emphasis is on the drug and its uses.) |
. Pharmacotherapeutis | deals with use of drugs in prevention & treatment of disease, usually to alleviate symptoms or, sometimes, to alter the course of the disease. The emphasis is on the disease and the treatment thereof. |
Chemotherapeutic agents: | are drugs with minimal effects in man but destroy or eliminate pathogenic cells or organisms (anticancer drugs; anti-infectives). |
Toxicology: | deals with adverse effects of drugs. |
The relative toxicity of a drug is expressed as___________ ( Most commonly in pharmacology this is the ratio of the dose capable of killing 50% of animals (LD50) over that required to achieve a beneficial effect in 50% of the animals (ED50). | the therapeutic index In clinical terms, a drug that has a “small therapeutic index” has little difference between the therapeutic dose and the dose that causes toxicity (eg, digoxin). |
Tolerance | Pharmacodynamic tolerance, Metabolic tolerance |
Pharmacodynamic tolerance CROSS TOLERANCE may develop between drugs within a class (e.g., opioids) or between drugs of different classes that produce similar pharmacologic effects (e.g., alcohol & inhaled anesthetics). | is hyporeactivity that occurs from chronic exposure to a drug (such as an opioid or alcohol). When tolerance develops, usually increasing doses are needed to provide a therapeutic effect. This is attributed to neuronal adaptation or cellular tolerance. |
Metabolic tolerance | is defined as decreased response to a dose of a drug which develops because of an increase in rate of elimination of the drug (enzyme induction is an example). The opposite can also occur, that is, enzyme inhibition. |
enzyme induction | as decreased response to a dose of a drug which develops because of an increase in rate of elimination of the drug |
enzyme inhibition | an increased response to a dose of a drug ?????look up |
down regulation | Another reason for a need in increased dose is a decrease in the number or sensitivity of receptor sites after continued dosing |
up regulation | The opposite of down regulation also occurs. For example, in response to constant depression of receptors (as with beta blockers), the body may either increase the number of receptors or increase the sensitivity of receptors. |
A change in receptor numbers may also be caused by other hormones. For example, thyroid hormones increase both the number of beta-receptors in heart muscle and cardiac sensitivity to catecholamine | change in receptor numbers caused by hormones |
Up regulation and down regulation may contribute to two clinically important phenomena: | first, tachyphylaxis or rapid tolerance to the effect of some drugs, and second, the “overshoot” phenomena that follow withdrawal of certain drugs. |
Idiosyncrasy | describes an unusual effect of a drug. It usually occurs in a very small percentage of patients and may not be related to the dose of the drug |
Side effect | usually describes any action of the drug other than the desired (therapeutic) effect. UNTOWARD EFFECT (or ADVERSE EFFECT) is any noxious, unintended, and undesired effect that occurs at normal drug doses |
. Food, Drug & Cosmetic Act and Amendments:Pure Food and Drug Act).prove the drug is safe and effective | This law was initially developed to improve quality and labeling of updated through the years to test for to restrict certain drugs to prescription use, and to prove the drug is safe and effective |
Amendments to the Federal Food, Drug, and Cosmetic Act enacted in 1962 mandate that drug manufacturers seeking federal approval to market a new drug must prove that | it is safe and effective and that the proposed label is accurate and adequate |
Comprehensive Drug Abuse Prevention and Control Act (1970 | 1970 |
Controlled Substances Act, enforced by the Drug Enforcement Agency (DEA), The prescriber must register with DEA and receive a DEA number to prescribe scheduled drugs. | classifies potentially addictive substances into schedules (I through V) and sets requirements for documentation and storage of these substances as well prescription orders and filling of such orders. |
Schedule I (Written C-i): Addictive substances with no approved use | (e.g., heroin) |
C-ii: Highly addictive substances | (e.g., morphine; amphetamine). must be written in ink or typed or submitted using electronic prescribing procedures and cannot be refilled. |
C-iii & C-iv: Less addictive; may be prescribed orally and may be refilled up to 5 times in 6 months | (e.g., aspirin with codeine C-iii; diazepam C-iv) |
C-v: Low addictive potential. Texas law now requires a prescription for C-v drugs | so essentially, in Texas, there is no difference in prescribing or how schedules iii, iv & v are handled. |
: Pharmacokinetics | is the quantitative study of the absorption, distribution, metabolism and excretion of drugs and their metabolites. In simple terms, pharmacokinetics (often simply called “kinetics”) is what the body does to the drug |
three most important ways by which drugs cross cell membranes are | through channels, active transport, or direct penetration. |
he primary method of passage of drugs across plasma membrane is by | |
Practical example: propranolol and nadolol are both non-selective beta-blockers. | Propranolol lipid soluble (nonpolar), nadolol water soluble (polar). Propranolol rapidly & completely absorbed from the gut, has a large first pass effect (70%), metabolized by hepatic metabolism, crosses the blood brain barrier produce CNS side effects |
. Nadolol is poorly absorbed (30%), has no first pass effect, is primarily eliminated as such by renal filtration, | and does not cross the blood brain barrier |
Carrier mediated membrane transport | Active transport |
Active transport | of some drugs (e.g., levodopa) occurs across neuronal membranes, the choroid plexus, renal tubular cells, and hepatocytes |
Active transport is characterized by | selectivity, competitive inhibition by congeners (similar drugs or metabolites), a requirement for energy, saturability, and movement against an electrochemical gradient |
The absorption of levodopa (an aminoacid) is interfered with by proteins (amino acids) in foods; | hence, in the treatment of Parkinson’s disease, administration of levodopa with meals may result in decreased absorption of levodopa because of competition for active transport mechanisms in the gut.) |
Facilitated diffusion | a carrier-mediated transport process but there is no input of energy. The substance moves according to electrochemical gradient (some amino acids |
Entry into cells is facilitated by | a large number of transporters on the plasma membrane. On the other hand, some transporters (e.g., p-glycoprotein) move chemicals out of cells. |
ABSORPTION | the transfer of a substance from the site of application to the blood stream (usually the systemic circulation). |
"Bioavailability | is defined as the fraction of unchanged drug reaching the systemic circulation following administration by any route |
Absorption of Drugs from the GI Tract | For drugs administered orally, bioavailability may be less than 100% because of either incomplete extent of absorption or first-pass elimination (in both the gut and the liver). |
Absorption of Drugs from the GI Tract | Bioavailability is the fraction of unchanged drug reaching the systemic circulation following administration by any route” |
Absorption of Drugs from the GI Tract). First pass effect | refers to the rapid hepatic inactivation of certain oral drugs on their first pass through the liver |
first-pass elimination | orally administered drugs may also be metabolized in the gut, in the gut, liver, or excretion into bile is called |
. Drugs given with fluid on an empty stomach will quickly pass from the | stomach into the intestine. |
Most drugs given with food will have | delayed absorption because of delayed stomach emptying |
The absorption of most drugs given orally occurs in the | small intestine. |
Some drugs may be metabolized by enzymes | in the gut (e.g., digoxin) or gut wall. |
Cytochrome P450 3A4 is found in both | enterocytes (in the gut] as well as hepatocytes [in the liver]. |
is a drug efflux system also found in enterocytes (there are a number of “drug transporters” found in the body). | |
P-glycoprotein | It is not an enzyme but it excretes drugs back into the intestinal lumen and decreases absorption. |
P-glycoprotein | is also found in the kidney and brain |
Digoxin is sometimes used as a probe for | for p-glycoprotein activity |
Chemicals found in grapefruit juice inhibit intestinal (but not hepatic | CYP 3A4 and possibly P-glycoprotein, increasing the bioavailability of a number of drugs ) |
The metabolism of a drug on the first pass through the liver itself is termed | first pass effect or first pass hepatic elimination. |
Sublingual & transdermal administration avoids | hepatic first pass effect. |
Drugs with a large first pass effect have a low | bioavailability |
prodrugs, | |
About 50% of the dose of a drug given rectally will avoid | 1st pass effect |
capsules filled with tiny spheres” | sustained release preparations |
formulations that provide slow (sustained) release, such as the OROS system (Procardia XL’ Concerta) or tablets with the drug mixed in a wax base (Toprol XL). | |
By definition, syrups contain | sugar |
elixirs contain | alcohol |
suspensions need . | shaken |
Sustained release and enteric formulations should not be | chewed or crushed. |
DISTRIBUTION | the process of a substance leaving the blood stream and moving to cells or tissues. |
Distribution phases | Absorptive phase, Calculation of Volume of Distribution ,Determination of Half Life |
Absorptive phase | distributed into interstitial/ cellular fluids then various tissues. In blood, the drug may be “free” or bound to plasma proteins. free drug i further distributed. |
absorptive phase 1st phase | Heart, liver, kidney, brain, & other highly perfused organs receive most of drug in initial phase of distribution. |
Absorptive phase 2nd phase | A second phase involves delivery of the drug to muscle, viscera, skin, and fat (minutes to hours before equilibration). This is limited by blood flow but involves far larger fraction of body mass. |
Distribution is also limited by drug binding to plasma proteins | blood levels” measures both bound and free drug in the blood but does not include drug bound in tissues or at receptor sites. |
The concentration gradient across the plasma membrane for the diffusible fraction (lipid soluble, nonionized, unbound) determines both r | rate and direction of net transfer between plasma and tissues |
Membrane transport systems may play a role in | in entry into or exit of drug out of tissues. |
Membrane transport systems | transport proteins, both influx and efflux systems, found in most tissues. |
P-glycoprotein | well-known drug efflux transporter found in the gut, kidney, and brain. |
P-glycoprotein appears to have an important role in | decreasing drug absorption from the gut, removing drugs from the brain, and transporting drugs from the blood into the kidney tubules |
A hypothetical quantitative estimation of drug distribution is called | the volume of distribution (Vd). This provides some estimate of how much drug has entered the body and where it went (e.g., extracellular fluids; muscle; fat tissue). |
Calculation of Volume of Distribution | The volume of distribution (Vd) is a mathematical expression of the sum of the apparent volumes of the compartments that constitute the body |
Vd relates the amount of drug | in the body to the concentration of drug in the blood (or plasma) |
Vd relates the amount of drug | It does not necessarily refer to an identifiable physiological volume but merely to the fluid volume that would be required to account for all of the drug in the body (based on the amount found in a blood sample |
A drug with a large Vd is bound in | in peripheral tissues (e.g., fat and muscle) |
a drug with a small volume of distribution is primarily | in plasma or extracellular fluids. |
Distribution & Elimination phases | The body handles most drugs by 1st order reactions, e.g., rate of absorption and elimination is proportional to concentration |
Distribution & Elimination phases a. The body handles most drugs by | 1st order reactions |
Distribution & Elimination phases a. The body handles most drugs by 1st order reactions, e.g., | ., rate of absorption and elimination is proportional to concentration Distribution & Elimination phases |
The body handles most drugs by 1st order reactions | e.g.,. The higher the blood concentration, the faster it is eliminated. |
1st order reactions | The clearance is constant over the concentration range encountered in clinical settings, i.e., elimination is not saturable, and the rate of drug elimination is directly proportional to concentration.” These drugs will usually have a constant half-life. |
Some few drugs operate at zero order | where rate is independent of concentration (; sometimes called saturation kinetics, capacity-limited elimination, or Michaelis Menten kinetics). |
). Alcohol; aspirin at high concentrations, & phenytoin at therapeutic concentrations are the best known drugs | with zero order elimination |
zero order elimination | example, alcohol is eliminated at a rate of 10 cc./hour regardless of the amount of alcohol consumed |
Some texts state that the elimination of drugs is concentration dependent | This means the higher the concentration of drug the longer it will take to eliminate the drug. alcohol is eliminated at a rate of 10 cc/hour regardless of the concentration. 10 cc = one hr to (clear) drank 3 ounces (90 cc) /alcohol = 9 hr to clear |
Determination of Half Life | Half-life is the time it takes for 50% of the drug in the body to be eliminated from the body. |
Determination of Half Life | However, when we measure "half-life" we determine the time it takes plasma concentration to be reduced by 50%. |
the plasma elimination half life symbolized as ßt½). | However, when we measure "half-life" we determine the time it takes plasma concentration to be reduced by 50%. |
drug’s half-life can vary greatly from patient to patient (usually associated with impairment | of the liver or kidneys but also by genetic variations in metabolizing enzymes). |
The half-life can be determined from a plasma elimination curve graph (figure 1.12, p. 11 Lippincott) or can be calculated. | |
be calculated. Half-life changes inversely with clearance (Cl) and directly with volume of distribution (V), hence | βt½ = 0.693 x V/Cl |