Introduction to Pharmacology Flashcards by Venice Camille Patricio

These are poisons of biologic origin

toxins

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Study of substances that interact with living systems through chemical processes especially by binding to regulatory molecules and activating or inhibiting normal body processes

Pharmacology

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These are drugs that have almost exclusively harmful effects

Poisons

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Pharmacology is the basic knowledge concerned with the action of:

chemicals on biologic systems

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Branch of pharmacology that deals with the undesirable effects of chemical on living systems, from individual cells to human to complex systems

Toxicology

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This speaks of what the drug does to the body

pharmacodynamics

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Science of substances used to prevent, diagnose, and treat diseases

Medical Pharmacology

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This speaks of what the body does to the drug

pharmacokinetics

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Pharmacodynamics is also known as the ___________ of the drug

Mechanism of action (MOA)

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This major drug-receptor bond is important in the interactions of highly lipid-soluble drugs with the lipids of cell membranes and perhaps in the interaction of drugs with the internal walls of the receptor “pockets”

hydrostatic interactions

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What major type does the acetyl group of aspirin use to bond with COX to effectively barricade the COX active site and block the synthesis of COX-2?

covalent bond

**3 major bonds:
Covalent bonds
Electrostatic bonds
Hydrophobic interactions

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These are the components of discussion for pharmacokinetics (4)

Absorption
Distribution
Metabolism
Excretion

of the drug

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This is any substance that brings about a change in biologic function through its chemical actions

Drug

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This is a specific molecule that drugs interact with in biologic system that plays a regulatory role

receptor

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True or False: (give rationale)

Drugs that bind through weak bonds to their receptors are generally more selective than drugs that bind by means of very strong bonds

False:

Drugs that bind through weak bonds to their receptors are generally more selective than drugs that bind by means of very strong bonds
→ Rationale: weak bonds require a very precise fit of the drug to its receptor if an interaction is to occur.

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This is the first line treatment for a certain disease

Drug of Choice (DOC)

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This term also pertains to DOC in that it is the best treatment option for the disease based on affordability, safety, sustainability, and efficacy

Rational drug use (RDU)

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What event brings about the effects of drugs?

drug-receptor interactions

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This is any article used in the mitigation, diagnosis, prevention, and cure of disease in man and in animals

drug

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These are specific molecules in a biologic system with which drugs interact to produce changes in the function of the system

receptors

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In order to respond to the proper chemical signal, receptors should be _________ in ligand-binding characteristics

selective

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In order to bring about the functional change, receptors should be _________ when they bind

modifiable

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This is a molecule to which a drug may bind without changing any function.

inert binding site

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Plasm albumin is a nonregulatory molecule to which drugs bind, but do not result to any detectable change in the function of the biologic system; hence, it is called an:

inert binding site

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This molecule to which drugs bind affects the distribution of drug within the body and determines the amount of free drug in the circulation; hence, making in a vital component of pharmacokinetics

inert

This molecule to which drugs bind affects the distribution of drug within the body and determines the amount of free drug in the circulation; hence, making in a vital component of pharmacokinetics

inert binding site

This is known as the "Law of Pharmacodynamics" that theorizes the combination of drug molecule with a receptor for which it has affinity and the initiation of the pharmacological response by intrinsic factors

Drug- Receptor Occupancy Theory

This theory states that there exist receptors if maximal drug response (Emax) is obtained at less than maximal occupation of the receptors (Bmax)

Spare receptor theory

What is the nature of receptor (according to location) for anesthesia and beta-blockers?

intracellular

What are the two types of drug receptors according to location?

Intracellular and Extracellular

What are the types of drug receptors according to function?

Enzymes Regulatory Transport/Channel Structural Orphan

What type of drug receptor according to function make up most of the receptors?

enzyme receptors

What type of drug receptors according to function do NSAIDs inhibit?

enzyme: cyclooxygenase - to prevent the formation of PGs which are mediators of pain and inflammation

Ranitidine blocks what type of drug receptor according to function?

Regulatory: H2 (histamine receptor 2 - gastric mucosa) - prevents release of H2 from gastric mucosa to prevent production of gastric acids

What is the specific type of histamine receptor that functions for allergic reactions?

Among the most important stabilizers are the many substances used clinically as local anesthetics, including procaine and tetracaine. Most of these agents act directly on the activation gates of the sodium channels, making it much more difficult for these gates to open and thereby reducing membrane excitability. Hence, these drugs are of the type:

Regulatory

Vinca alkaloids act upon tubulin by preventing it from forming into microtubules; hence, preventing cell division. These drugs, therefore, are of the type:

structural

Mebendazole and colchicine act on the drug receptor type:

structural: Mebendazole (anti-helminthic) - inhibits microtubule formation Colchicine (anti-gout) - alters the movement of cells like neutrophils

These are drug receptors of unknown ligands and are useful targets for future drug development

orphan receptors

This pertains to the combining of a drug molecule with the receptor for which it has affinity, and the initiation of a pharmacologic response by its intrinsic activity

drug-receptor interaction

What are the 3 requirements of drug-receptor interaction?

Well-fitted Highly specific Definite

This pertains to the activity of receptors in the absence of ligands

constitutive activity

This is a drug capable of fully activating the effector system when it binds to the receptor

Full agonist

This is a drug that produces less than the full effect, even when it has saturated the receptor

Partial agonist

True or False: In the presence of a full agonist, a partial agonist acts as an inhibitor

True

These drugs bind with equal affinity to the inactive and active receptor states and prevent binding by an agonist and preventing any deviation from the level of constitutive activity

Neutral antagonists

These drugs have a higher affinity for the inactive receptor state than for active receptor and decrease or abolish any constitutive activity

inverse agonist

True or False: Antagonistic drugs have intrinsic activities

False Antagonist has affinity to the receptor but no intrinsic activity. Its primary action in to reduce the effects of agonists that normally activate receptors

This type of antagonist interaction has weak attraction of the ligand and the receptor; hence, easy dissociation

Reversible (temporary inhibition)

This type of antagonist interaction involves covalent binding and reduces Emax, but not necessarily EC50

Irreversible

This type of antagonist surmountability overcomes the effect of the antagonist by increasing the dose of the agonist

Competitive

This type of antagonist surmountability does not allow the agonist to surmount the inhibitory effect once the receptor is bound the drug irrespective of agonist's concentration

Noncompetitive

The degree of inhibition produced by a competitive antagonist depends on:

the concentration of antagonist

Clinical response to a competitive antagonist also depends on the concentration of ________ that is competing for binding to receptors

agonist

This is a positively charged non-drug chemical that is used as antidote for heparin poisoning by acting via ionic binding to inactivate the anticoagulant property

protamine sulfate Nature of antagonism: Chemical

This type of antagonism according to nature cancels the end effects

Physiologic

This drug results to competitive full effects for morphine (an opioid agonist)

naloxone (opioid antagonist)

Pharmacologic interactions that occur when the combined effect of two drugs is greater than the sum of their effects when given separately

Synergism (1+1 = 11)

Pharmacologic interactions that occur when one drug does not elicit a response on its own but enhances the response to another drug.

Potentiation (1+0= >1)

What type of diet should not be recommended for patients with decreased Fe or Ca absorption?

High vegetable diet that decreases Fe & Ca absorption by acting as chelators of the metal ions

This juice is an inhibitor of CYPP450 which leads to decreased metabolism of some drugs

grapefruit juice

This is an herb that increased the metabolism of digoxin via CYP induction which decreased its effects

St. John's Wort

This pertains to the relationship between a drug's molecular structure and the drug's biological activity

Structure Activity Relationship (SAR)

This is the concentration of drug that produces 50% of maximal effect

EC50 half maximal effect concentration

This pertains to the peak effect/ maximal response that can be produced by the drug

Emax

Symbol for dissociation constant

This represents the concentration of free drug at which half-maximal binding is observed

Kd; dissociation constant

This pertains to the total concentration of receptor sites (i.e., sites bound to the drug at infinitely high concentration of free drug)

Bmax

This refers to the plateau portion of the curve or the constant peak effect or the situation wherein the overall intake of a drug is fairly in equilibrium with its elimination

Steady-State Concentration (SSC)

It is generally considered that steady state is reached when a time of ___________ is achieved for a drug after regular dosing has started

4 half-lives

This pertains to the time-concentration profile of a drug after a dose

Area Under the Concentration Curve (AUC)

This reflects the actual body exposure to drug after administration of a dose of the drug

Area Under the Concentration Curve (AUC)

The AUC is directly proportional to _____ and inversely proportional to _____

Directly proportional to dose and Inversely proportional to rate of elimination

This expresses an individual's response to gradual increasing doses of a given drug

Grade-Dose Response Curve

The Graded-Dose Response Curve provides data on pharmaceutical ______ and ______ of a druh in relation to the desired therapeutic effect

pharmaceutical potency and maximal effect of a drug

This curve shows that there is a drastic change with small changes or shift in the dose

a Steep Dose-Response Curve

This curve may have important clinical consequenes if the upper portion of the curve represents an undesireable extent of response

a Steep Dose-Response Curve

In plotting the dose-response curve, what is indicated in the x-axis

dose/log dose

In plotting the dose-response curve, what is indicated in the y-axis

degree of response

This pertains to the maximum achievable dose

efficacy

This pertains to the smallest dose that produces the maximal effect

ceiling dose

This pertains to the dose required to achieve 50% of the max response

potency (EC50)

This pertains to the degree of change in response with a change in dose

slope

This indicate the potential variability of responsiveness among individuals (population-based)

Quantal Dose Reponse Curve

The Quantal Dose Response Curve generate information regarding the ____________ to be eexpected from a particular drug used to produce a specified effect

margin of safety

In the Quantal Dose Response Curve, what is indicated in the y-axis?

cumulutative number of respondents (x-axis is log dose)

This pertains to the median toxic dose producing death in 50% of test animals

Lethal Dose (LD50)

This pertains to the median toxic dose producing a toxic effect in 50% of test animals

Toxic Dose (TD50)

This pertains to the dose required to produce the therapeutic or pharmacologic effect in 50% of the population

Therapeutic dose (ED50)

This pertains to the dose at which 50% of the individuals exhibit the specified quantal effect

Median effective dose (ED50)

This pertains to the dose required to produce a particular toxic effect in 50% of animals

Median toxic dose (TD50)

This pertain to the dose required to produce death in 50% of animals

Median lethal dose (LD50)

This deals with different processes in the body which the drug undergoes as it reaches its biologic site of activity and leaves the system. This is essentially what the body does to the drugs

pharmacokinetics

Pharmacokinetics deals with the process of:

Absorption Distribution Metabolism Excretion

Metabolism and Excretion are collectively known as:

Elimination

This process of pharmacokinetics pertains to the permeation of the drug to the system by means of simple passive diffusion, by any route of administration.

Absorption

Drug permeation proceeds by which mechanisms?

Aqueous Diffusion Lipid Diffusion Special Carriers Endocytosis and Exocytosis

This mechanism of drug permeation is usually driven by the concentration gradient of the permeating drug, a downhill movement

Aqueous Diffusion

Aqueous Diffusion is governed by which law?

Fick's Law of Diffusion

Drug molecules DO NOT PERMEATE if:

- They are bound to plasma proteins - They are charged/ionized

This is the dominat blood proteins involved in protein binding

albumin

Albumin are selective for:

weak acids (since it is a base)

The α-1-Acid glycoprotein (orosomucoid) is selective for:

weak bases (since it is a weak acid)

This blood protein has a selective structure as it binds hormones

globulin

This mechanism is the most important limiting factor for drug permeation because of the large number of lipid barriers that separate the compartments of the body.

Lipid diffusion **recall that lipid bilayer is dominantly lipophilic

This determines how readily the molecule moves between aqueous and lipid media

lipid:aqueous partition coefficient

If K is higher, substance is more _________ soluble; hence, there is greater passive transport

Lipid soluble *K is the partition coefficient K = solubility in lipid layer/solubility in aqueous layer

If an acidic drug is exposed to a basic environment, it woould be deprotonated. Hence, it will be: A. More lipid soluble B. More soluble in aqueous layer

B. More soluble in aqueous layer **Since charged particles attract water molecules

Which equation expresses the ratio of lipid-soluble form to water-soluble form for a weak acid or weak base?

Henderson-Hasselbalch equation

This mechanism of drug permeation exists for many substances that are too large or too insoluble in lipid to diffuse passively through membranes

Special carrier

What are the three characteristics of special carriers of drugs that differentiares it from passive diffusion?

selective saturable inhibitable

This mechanism is undertaken by vitamin B12 for transport while it is complexed with the binding protein Intrinsic Factor

Endocytosis

This mechanism is undertaken by neurotransmitters in order to exit the cell

exocytosis

Which law gives the passive flux of molecules down a concentration gradient?

Fick's Law of diffusion

What is the denominator for the Fick's law fomula for Flux?

η = thickness of the membrane

What is the numerator for the Fick's law formula for Flux?

d ⋅ A (C1−C2) d = diffusion coefficient/ permeation coefficient A = surface area of the membrane C1−C2 = Difference in concentration gradient

True or False: Acidic drugs will be absorbed if the pH is low (acidic), and basic drugs will be absorbed if the pH is high (basic)

True (since they will not be ionized)

What is the formula for pH for the Henderson-Hasselbalch equation?

𝑝𝐻 = 𝑝𝐾𝑎 + log (𝑐𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 𝑢𝑛𝑝𝑟𝑜𝑡𝑜𝑛𝑎𝑡𝑒𝑑/𝑐𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 𝑜𝑓 𝑝𝑟𝑜𝑡𝑜𝑛𝑎𝑡𝑒𝑑)

According to Henderson-Hasselbalch equation, the numerator and denominator should be _________ and _________ respectively in acidic drugs

numerator: anion (deprotonated) form denominator: neutral/unionized form

If the pH of the environment is greater than the pKa of the acidic drug, then the drug's state is said to be in what state?Absorption of the drug will also be:

deprotonated and ionized state absorption will be less = favorable excretion

Which of the following will be the treatment goal in handling the toxicity of acidic drugs? A. acidify urine B. alkalinify the urine C. acidify the blood pH D. administer ammonium chloride E. NONE of the above

B. alkalinify the urine alkanifying the urine will mean acidic environment for the drug; hence, the acidic drug will be deprotonated and ionized which will favor excretion since absorption will be less. We do this by administering sodium bicarbonate, NOT ammonium chloride which will acidify urine

If the pH of the environment is greater than the pKa of a basic drug, then the drug exists in what state? Absorption of the drug will also be:

deprotonated and non-ionized state more absorption

Which of the following is correct therapeutic intervention when handling toxicity of basic drugs? A. alkalinify blood pH B. alkalinify the urine C. administering sodium bicarbonate D. administer ammonium chloride E. NONE of the above

D. administer ammonium chloride Ammonium chloride will acidify the urine which means that the environment of the drug has a pH of less than the pKa of the basic drug. This will promote excretion of the drug as it is protonated and ionized.

This process of pharmacokinetics pertains to the drug-receptor interactio upon reaching the target cell, resulting to processes that end in the pharmacodynamic effects of the drugs

Distibution

This process of pharmacokinetics aims to convert a relatively less polar parent drug to a more polar metabolite facilitating easier excretion

Biotransformation

Which organ is mainly responsible for hte biotransformation of drugs?

liver

This pertains to the extensive metabolism of the drugs in the liver that are absorbed via the portal circulation

First-pass effect

Unlike other drugs, inhalation drugs are mainly metabolized in which organ?

Lungs **The major site of drug metabolism is in the liver

The order of reaction wherein the amount of the drug eliminated for each time interval is constant, regardless of the amount of drug in the body

Zero Order Reaction

The order of reaction wherein constant fraction of drug is eliminated

First ORder Reaction

Order of reaction that is concentration independent

Zero oder reaction

This order of reaction in which amount of drug eliminated in a set amount of time is directly proportional to the amount of drug in the body

concentration dependent

What is the rate and half life equation for the zero order elimination?

Rate equation: [A𝑡]=[A𝑜] - kt Half life: (0.5 x C𝑜) / k𝑜 C𝑜: concentration at time = 0 k𝑜: zero order rate constant

What is the rate and half life equation for the first order elimination?

Rate equation: ln[A𝑡]=ln[A𝑜] - kt Half life: 0.693 / k1 = 0.7 / k1: first order rate constant

This pharmacokinetic parameter relates the amount of drug in the body to the concentration of drug in the blood plasma

volume of distibution

This parameter of pharmacokinetic pertains to the time required to change the amount of drug in the body by one-half during elimination

Half-life

What is the formula for half-life of a drug?

𝑡1/2 = (0.7 𝑉𝑑) / 𝐶𝑙

The approximate duration of the presence of the drug in the system is 4 half-lives. To compute for the dosing interval, the formula is:

[4 x (t1/2)] / 2

Formula for the Rational Drug Dosing Regimen (RDDR)

RDDR = (t1/2) / target concentration

Accummulation is inversely proportional to the:

fraction of the dose lost in each dosing interval

Give the formula for the Accummulation Factor

AF = 1/fraction lost in 1 dosing interval AF = 1/(1 – fraction remaining)

The major carrier plasma protein for acidic drugs

albumin

The carrier plasma protein for basic drugs

alpha-1-acid glycoprotein

This is the most important factor that dictates drug plasma concentration

Clearance -measure of the ability of the body to eliminate the drug

Formula for clearance:

Clearance = Rate of elimination / concentration Clearance (1st order) = Dose / area under the curve

This pertains to the sum of the individual clearances in the kidney, liver, lungs, etc.

Cl𝑡𝑜𝑡𝑎𝑙 ** clearance is additive

True/False: Most of the drugs follow first-order elimination

True

This type of drug elimination is indicated when clearance varries depending on the concentratio nof the drug that is achieved

Capacity-limited elimination

Formula for the Michaelis-Menten elimination:

Rate of elimination = (Vmax x C) / (Km + C) Michaelis-Menten Elimination is also known as Capacity -Limited Elimination

According to Michaelis-Menten elimination, Vmax pertains to:

Maximum elimination capacity

According to the Michaelis-Menten equation, Km pertains to:

the drug concentration at which the rate of elimination is 50% of Vmax

True / False: According to Michaelis-Menten elimination, at high concentration, rate of elimination is directly proportional to concentration

False: At high concentration, rate of elimination would not increase due to saturation At low concentration: Rate of elimination is directly proportional to concentration

What is the main determinant of drug delivery to the organ of elimination?

Blood flow to the organ **Flow-limited elimination: elimination is dependent on the rate of drug delivery to the organ of elimination

What are components of total clearance?

Hepatic, Renal and Biliary clearance

What are the factors that influence clearance?

Dose Organ blood flow Intrinsic flow of the liver and kidneys

What is the bioavailability for IV drugs?

100% BA All of the IV drugs enter the systemic circulation

Which route of administration has the lowest bioavailability? (5 to <100)

per orem (PO) **the most convenient; first-pass effect may be significant

Which route of drug administration is usually used for lack of first-pass effect and has prolonged duration of action?

transdermal

This pertains to the measure of the rate and extent of drug entry into systemic circulation

bioavailability

This pertains to the measure of similarity in the bioavailability of a generic drug product to the bioavailaility of the reference drug product

bioequivalence

This is a biological product that is highly similar to and has no clinically meaningful difference from an existing FDA-apporved refernce product

biosimilar **Biological products (or biologicals, or biologics) are pharmaceutical products from living organisms or virus (eg. vaccines, hormone products, monoclonal antibodies, etc.)

This is the basis of drug dose used by physicians in dosing computations

kilogram body weight (KBW; kg BW)

This is the initial dose that promptly raises the concentration of drug in the plasma to target concentration

Loading dose (D𝑙)

What is the formula for Loading Dose?

Volume distribution x Target concentration

This is the dose given to maintain a steady state of drug in the body

maintenance dose

What is the formula for Maintenance Dose?

Dosing Rate x Dosing Interval

Dosing Rate formula

(Clearance x Total concentration) / Bioavailability

What are the 4 different processes involved in biotransformation?

Detoxification Activation More activation Simplification

This phase of biotransformation aims to convert the parent drug to a more polar metabolite by introducing or unmasking a functional group (-OH, NH2, -SH)

Phase I (non-synthetic reaction) Functionalization phase

What are the 2 microsomal enzymes involved in the Phase I of biotransformation oxidation-reduction process?

NADPH-cytochrome P450 oxidoreductase (CPR or POR; a flavoprotein) Cytochrome P450 (terminal oxidase; a hemoprotein) **recall respiratory chain

Which of the following in not a membrane recptor that is directly coupled to ion channel? A. Nicotinic receptors B. Muscarinic receptors C. Glycine receptors D. GABAₐ receptors E. Serotonin receptors

B. are GPCR

In first-order elimination, clearance is calculated from the dose divided by the:

AUC

Clearance is computed from rate of elimination divided by:

concentration

What is the nature of antagonism when drug effect is antagonised by formation of a complex bwteen effector drug and another compound?

Chemical antagonism

Which of the following is not a Gi-coupled receptor? A. a1 B. D2 C. D3 D. D4

A. alpha 1 is a Gq