Pharmacology Flashcards by Rohmat Ali

is the study/science of chemicals (drugs) that interact with the human body, is defined as what

pharmacology

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what a drug does to the body (biological effects and mechanism of action) is defined as

pharmacodynamics

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what the body does to a drug (absorption, distribution, metabolism and excretion of drugs and their metabolites), is defined as

pharmacokinetics

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the science and technique of preparing, dispensing and reviewing of medical drugs) , is defined as

pharmacy

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What is a drug:

any single synthetic, or natural, substance of known structure used in treatment, prevention or diagnosis of disease.

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what is a medicine

a chemical preparation, containing one or more drugs used with the intention of causing a therapeutic effect

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do drugs work by acting on target molecules

yes or no

yes

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what s a ligand

In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose.

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drugs acting or receptors can either be what

agonist or antagonists

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is a drug/chemical that activates a receptor and causes a response (acetylcholine), is an example of what

agonist

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is a type of drug which combines with a receptor but does not activate it. Thus blocking the action of the agonist by binding to the same receptor.

is an example of what

antagonists

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what must there be, for the binding between the receptor and agonist

affinity

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define affinity

Affinity is the strength of association between ligand and receptor.

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once the agonist has combined the receptor is activated, what is the next response

efficacy response

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what is efficacy

Efficacy is the ability of an agonist to evoke a cellular response

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Affinity is ‘strength of association’ between ligand and receptor

how would low affinity affect the dissociation rate

Low affinity = fast dissociation rate

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Affinity is ‘strength of association’ between ligand and receptor

how would moderate affinity affect the dissociation rate

Medium affinity = moderate dissociation rate

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Affinity is ‘strength of association’ between ligand and receptor

how would high affinity affect the dissociation rate

High affinity = slow dissociation rate

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efficacy is the ability of an agonist to evoke a cellular response

if there is a low affinity, how will that affect the cellular response (efficacy)

If there is a low affinity, then there will be small cellular response

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efficacy is the ability of an agonist to evoke a cellular response

if there is a high affinity, how will that affect the cellular response (efficacy)

If there is a high affinity, then there will be a greater cellular response

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what do antagonists possess and lack

possess affinity and lack efficacy

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the process by which a drug enters the body from its site of administration and enters the general circulation: is defined as what

Absorption

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the transport of drug by the general circulation: is defined as what

distribution

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the process by which tissue enzymes (principally in the liver – hepatic metabolism) catalyze the chemical conversion of a frequently lipid soluble drug to an often less active and more polar form that is more readily excreted from the body: is defined as what

metabolism

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the processes that remove the drug, or its metabolites, from the body (principally the kidneys – renal excretion): is defined as what

excretion

the drug must dissolve (dissolution) in an aqueous environment order to be absorbed: is defined as what

solubility

some drugs are destroyed by acid in the stomach, or enzymes in the gastrointestinal tract. in a few instances, a compound is modified within the gut to release the active drug: is defined as

chemical stability

the ratio of the drug concentration in the membrane and concentration in water at equilibrium: is defined as what

partition coefficient

what does an acid donate proton or electron

protons

what does a base do

accepts a proton (decreases pH)

_Factors affecting gastrointestinal absorption_ Gastrointestinal mobility:

the rate at which the stomach is emptying and movement through the intestines, this is modified by some drugs, disease states and the presence of food.

_Factors affecting gastrointestinal absorption_ pH:

at the absorption site (varies along the gastrointestinal tract).

_Factors affecting gastrointestinal absorption_ Blood flow:

blood flow to the stomach and intestines (increased by food intake). Certain drugs are manufactured so that they can release drugs at different rates and sites.

_Factors affecting gastrointestinal absorption_ Physicochemical interactions:

the rate of absorption of drugs is modified by calcium rich-rich foods The presence of **transporters** in the membranes of epithelial cells of the g.i tract can facilitate drug absorption

what is oral availability of a drug

is the fraction of drug that reaches the systemic circulation after oral ingestion

what is the Systemic availability of a drug

is the fraction that reaches the systemic circulation after absorption

when would use the rectum to delive drugs

when oral route is compromised

what is the disadvantage of taking medication via the oral route

inactivation by some enzymes/acids food binding

what are the advantages of taking medication via the sublingual/buccal route

rapid absorption by-passes the portal system

what are the advantages of intravenous route for drugs

rapid onset continuous infusion complete availability of drugs that cause local tissue damage

what are the disadvantages of taking intravenous route

sterile preparation required risk of sepsis embolism high drug levels at the heart

what is the advantage of taking intramuscular drugs

rapid onset of lipid soluble drugs

A symptom that suggests a certain medical treatment is necessary, is defined as

**Indication:**

A specific situation in which a drug, procedure or surgery should not be used because it may be harmful to the person, is defined as

**Contraindication**:

acceptable if benefits outweigh risk, is defined as

**Relative contraindication:**

life threatening – do not take, is defined as

Absolute contraindication:

normal dose interval (given) is based on what

1 half life

when is the next dose given (dosage sechdule/interval)

* Next dose is given as previous dose reaches half life

define half life:

* Half-life: the time taken for the total amount of drug in blood plasma to diminish by half once it reaches peak concentration.

define overdose

**Overdose:** an excessive and dangerous dose of drug (paracetamol more than 10g lethal dose, codeine more than 350mg leads to CNS and respiratory depression).

define, ## Footnote **Drug-drug interactions**

where several drugs are prescribed simultaneously to patients where one drug modifies the response to the co-administrating drug

when effects or action of multiple drugs combine to produce adverse effect, is defined as

Pharmacodynamics

when one drug affects the delivery of another drug to its target. May involve absorption, metabolism or elimination, is defined as

Pharmacokinetic

is codeine safe to take during pregnancy

what are the 7 checklist, before prescribing drugs

1) Patient’s identity! 2) Patient’s age and gender 3) Medical History / other conditions 4) Any allergies 5) Any recent / current medication 6) Consider special conditions: Pregnancy, lactation, can they swallow tablets 7) Sugar free available?

the process by which a drug enters the body from its site of administration and enters the general circulation, is defined as

absorption

the transport of drug by the general circulation. Drugs most often leave the blood and enter perfused tissues, is defined as

distribution

metabolism

the processes that remove the drug, or its metabolites, from the body (principally the kidneys – renal excretion), but other routes may be important for specific agents, is defined as

excretion

for a drug to achieve effect, a drug must reach critical concentration in the plasma, what must it reach?

Minimum effective concentration (MEC)

ideally a drug should be below the level of causing significant unwanted side effects. what must a drug not reach to avoid side effects

maximum tolerated concentration (MTC)

what is the therapeutic window

is the blood plasma concetration between MTC and MEC

what is the consequence of a small therapeutic window

there is a chance you can overdose

drugs with smaller therapeutic window are classified as unsafe true or false

true

when is steady state of a drug achieved

drug adminsitration is equal to drug elimination

what is a loading dose

A loading dose is an initial increase dose taken to get to the therapeutic window and then decrease to a lower dose to maintain a steady state.

which is the main organ for drug metabolism

liver (hepatic metabolism)

where does first pass metabolism occur

in the liver

how does making a drug more hydrophilic help with elimination

hastens its excretion by the kidneys

what is the name of the substances after metabolism

metabolites

are metabolites more or less active then their parent form

less active

the mechanism involved to increase affinity for water or solubility in water for a drug is called what

hydrophilicity

the enzyme in the liver metabolising the drug needs to act on a wide variety of substances, and therefore must have a low what

low substrate specificity

drug metabolism occurs in two phases. what occurs during phase 1

addition of polar groups

drug metabolism occurs in two phases. what occurs during phase 2

conjugation

oxidation reaction is catalysed by a family of enzymes known as

cytochrome P450 oxidases

what occurs during phase 2

Cytoplasmic enzymes conjugate the functional groups introduced in phase 1.

where are cytochrome P450 oxidases found

they are found in the endoplasmic reticulum

what factors affect drug metabolism

* Enzyme inhibition * Naringin found in citrus fruits * Ciprofloxacin * Erythromycin * Herbal remedies

the process by which a drug enters the body from its site of administration and enters the general circulation: is the definition of what

absorption

the transport of drug by the general circulation. Drugs most often leave the blood and enter perfused tissues. Once within a tissue further, reversible, distribution dictated by a concentration gradient, may occur by diffusion (or carrier-mediated transport): is teh definition of what

distribution

metabolism

the processes that remove the drug, or its metabolites, from the body (principally the kidneys – renal excretion), but other routes may be important for specific agents: is the definition of what

excretion

is the mathematical analysis of all drug disposition factors (absorption, distribution, metabolism and excretion): is the definition of what

pharmacokinetics

when do drugs exhibit first-order kinetics

where the rate of elimination is directly proportional to drug concentration.

what determines the maintenane dose rate

clearance ## Footnote Probably the single most important pharmacokinetic parameter – the volume of plasma cleared of drug in unit time,

what must occur for a drug to achieve steady state

rate of drug administration = rate of drug elimination

an initial higher dose is given during treatment at the beginning before stepping down. what is the name of this initial dose

loading dose

The time for the concentration of drug in plasma (or the amount of drug in the body) to halve’ - is referred to as what

half life

which organ is responsible for the elimination of most drugs

the renal system (kidneys)

drugs are metabolised to become more ............. compounds which are are more easily excreted

polar

if drugs are lipid soluble, they are easily reabsorbed in the ................ by passive diffusion

renal tubules

Drugs or phase 1 metabolites that are not sufficiently polar to be excreted rapidly by the kidneys are made more hydrophilic by conjugation with endogenous compounds - by which organ

liver

which test is used to show how well the kidneys are working

Glomerular filtration rate (GFR)

what does a Glomerular filtration rate (GFR) estimate

* It estimates how much blood passes through the glomeruli every minute

what is a normal Glomerular filtration rate (GFR)

* Normal GFR is 90 mls / min or higher

a Glomerular filtration rate (GFR) of 60-89 mls/min = what stage

mild stage 2

a Glomerular filtration rate (GFR) of 30-59 mls/min = what stage

moderate stage 3

a Glomerular filtration rate (GFR) of 15-29 mls/min = what stage

severe stage 4

a Glomerular filtration rate (GFR) of 15-29 mls/min = what stage

established renal failure stage 5

drugs or its metabolites that have poor renal excretion cause what -

toxicity

if renal impairment is reduced, how does this affect the effectiveness of drugs

some drugs wont be as effective