Term
| What the 'body does to the drug'? |
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Definition
| Pharmacokinetics What the 'drug does to the body'... Pharmacodynamics.. |
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Term
| Components of Pharmacokinetics? |
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Definition
| - Drug Absorption - Drug Distribution - Drug Metabolism - Drug Excretion |
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Term
| Components of Pharmacokinetics? |
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Definition
- Drug Absorption
- Drug Distribution
- Drug Metabolism
- Drug Excretion |
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Term
| '___________________' characterizes the clinical applications, contraindications, drug interactions and adverse effects of drugs. |
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Definition
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Term
___________ are 'predictable' effects seen in 'all individuals' to a varying degree.
- Side effects
- Idiosyncratic reactions
- Allergic reactions |
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Definition
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Term
____________ reactions are 'unpredictable' , 'do not involve the immune system' and seen in a few patients..
- Side effects
- Idiosyncratic reactions
- Allergic reactions |
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Definition
Idiosyncratic reactions
(key words - Not seen in everybody + Do not involve the immune system + 'unpredictable') |
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Term
| Cathartic = Purgative = Laxative (mild cathartic) ... Egs.. |
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Definition
| Castor Oil, Epsom salts, Milk of magnesia |
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Term
- Antacids
- Chelating agents
- Osmotically active agents such as 1)diuretics (eg: mannitol)
2)Cathartic (eg: methyl cellulose)
- Volatile general anesthetics
are all examples of drugs.. that ... |
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Definition
| act independently of receptors |
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Term
| Drug potency of volatile general anesthetics correlates with their _____________ |
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Definition
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Term
Which kind of bond is involved in the formation of a a drug-receptor complex?
- Ionic
- Covalent
- Hydrogen
- Van der Walls |
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Definition
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Term
'Agonists' are
1) Drugs that bind to receptors and
2) ???? |
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Definition
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Term
'Antagonists' are drugs tht
- Bind to a receptors and
- ??????? and
- Do not ________ them |
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Definition
DECREASE or BLOCK the effect of an AGONIST
and do not STIMULATE the receptors.... |
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Term
Which of the following have zero efficacy?
1) Agonists
2) Antagonists |
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Definition
Antagonists
('cos they do not have the ability to stimulate the receptor) |
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Term
| When the antagonist and agonist are vying for the same receptor, the receptor is called the ____________ |
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Definition
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Term
| The effects of a competitive agonist can be overcome by? |
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Definition
| Increasing the concentrations of the agonist.. |
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Term
How do the competitive and non-competitive antagonists bind to their receptors?
- Reversibly ??
- Irreversibly ?? |
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Definition
Competitive agonists - Reversibly
Non-competitive agonists - Irreversibly |
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Term
| what is the effect of a competitive agonist on a dose-response curve? |
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Definition
| Produces a parallel right shift in the dose-response curve |
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Term
| What is the effect of a non-competitive agonist on the dose-response curve? |
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Definition
| Decreases the height of the dose-response curve |
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Term
| How can the effects of a non-competitive antagonist be overcome? |
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Definition
Cannot be overcome.. (due to the irreversible binding of the drug to the receptor..)
The duration of action depends on the turnover rate of the receptors.. |
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Term
| The effect of a drug is best analyzed by .. |
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Definition
| Plotting the response versus the log of the drug concentration. |
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Term
| Define 'efficacy' of a drug? |
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Definition
| It is the MAXIMUM RESPONSE that an agonist can produce. |
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Term
Define 'Potency' of a drug?
What are it's units of measurement? |
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Definition
Measure of how much drug is required to produce a given effect.
- It is expressed as a 'CONCENTRATION' that can elicit a EC50..(50% response)..
so the units of measurement are the units of concentration.. |
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Term
The less the drug required to produce an effect, the more ______ a drug is.
1) Efficacious
2) Potent |
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Definition
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Term
Potency increases if the dose-response curve
1) Shifts to the right?
2) Shifts to the left? |
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Definition
| Shifts to the left on the x-axis |
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Term
| Dose-response curve is otherwise called |
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Definition
| 'Exposure-response curve' |
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Term
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Definition
Term is 'Half Maximal Effective Concentration'.
Refers to the concentration of a drug which induces a response halfway b/w the baseline and the maximum after some specified exposure time.
Commonly used as a measure of a drug's POTENCY!! |
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Term
| How to interpret the EC50 of a 'graded dose response curve' to the EC50 of a 'Quantal dose response curve'? |
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Definition
EC50 of a graded dose response curve ==> concentration of the drug where 50% of its maximal effect is observed.
EC50 of a quantal dose response curve
==> Concentration of a compound where 50% of the POPULATION exhibit a response! |
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Term
| What are the co-ordinates of the graph in a 'QUANTAL dose-response curve'? |
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Definition
X-axis ==> log of the dose
Y-axis ==> % of the population responding' |
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Term
Difference b/w the following terms?
- ED 50
- TD 50
- LD 50 |
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Definition
ED50 ==> MINIMUM dose at which 50% of the population shows the effect
TD50 ==> MINIMUM dose at which 50% of the population experiences a specific TOXIC effect
LD 50 ==> MINIMUM dose that kills 50% of the individuals in the population. |
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Term
| Therapeutic Index (TI)==?? |
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Definition
Ratio of the dose of the drug required to produce a toxic or lethal effect to the dose needed for a therapeutic effect.
==> TD50/ED50 |
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Term
| which measure is used as an indication of drug=-safety? |
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Definition
| therapeutic index ==> TD50/ED50 |
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Term
| What does a low Therapeutic Index mean? |
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Definition
| That there is a relatively HIGH incidence of side-effects at usual doses (narrow range for therapeutic and toxic doses). |
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Term
| Example of a drug that has a TI less than 4? |
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Definition
Lithium ==> 2
Therefore, requires close patient monitoring.. |
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Term
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Definition
| Term representing the concentration of a drug at its site of action |
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Term
| What are the three factors that affect drug absorption from the site of administration? |
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Definition
- Permeability:
1) Lipid solubility
2) Aqueous solubility
3) Facilitated transport
- Bioavailability
- First-pass metabolism |
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Term
Which of the following is more lipid soluble?
- Strong acids and bases
- Weak acids and bases |
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Definition
Weak acids and bases (only their nonionized portions..)
Non-ionized particles are lipid soluble...
(Charged particles are water-soluble) |
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Term
| Do you think that charged particles can enter cells? |
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Definition
| Only if they are very small and can pass through the water-channels.. but cannot enter by dissolving in the plasma-membrane of the cell |
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Term
| 'Fraction of the drug that reaches the systemic circulation' is referring to the? |
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Definition
| Bioavailability of the drug |
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Term
| Which route of administration ==> 100% bioavailability? |
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Definition
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Term
| Sites of first-pass metabolism? |
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Definition
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Term
| Describe the route of a drug that is administered sublingually? |
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Definition
Sublingual mucosa --> Venous circulation --> Superior Venacava
Therefore bypasses the liver and thus, the first pass metabolism |
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Term
| Which route of administration is contraindicated for patients on anti-coagulant therapy? |
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Definition
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Term
Which route of absorption is described below?
- Only small volumes of drug can be given this way
- Relatively slowly absorbed |
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Definition
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Term
| Name sites on the body where a drug can be applied topically? |
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Definition
- Eyes
- Ears
- Nose
- Skin
- Vagina
- THROAT |
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Term
| Injectionof a drug into the subarachnoid space is through _______ technique |
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Definition
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Term
| Injection of a drug into the ventricular system is through _________? |
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Definition
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Term
| Advantages of using the intrathecal route? |
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Definition
- This route bypasses the blood-brain barrier and blood-CSF barrier
- Can be used when a high concentration of a drug is to be made available in a short period of time and when a drug has poor/slow CNS penetration |
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Term
| Route used for x-ray contrast studies? |
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Definition
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Term
| Define 'Volume of distribution'? |
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Definition
| The apparent/virtual volume into which a drug distributes |
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Term
| Formula for calculating the volume of distribution? |
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Definition
| Vd = Total drug in the body (g)/Plasma drug concentration (g/L) |
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Term
| Example of drugs whose Vd may be greater than the total body water? |
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Definition
| Drugs that are lipid-soluble (and are stored in body-fat) |
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Term
| Which drugs have a Vd that is almost similar to the plasma volume? |
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Definition
| Drugs which strongly bind to plasma proteins |
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Term
| What is teh relationship b/w Vd and elimination rate? |
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Definition
| The greater the Vd ==> the slower the elimination rate |
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Term
| The BBB is highly selective for certain type of drugs. What could be the characteristics of these drugs? |
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Definition
Have to be
- Lipid soluble
- Non-ionized |
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Term
| Egs. of drugs which 'induce metabolism' in the liver are: |
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Definition
- Barbiturates
- Phenytoin
- Rifampin
- Carbamazepine |
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Term
| Examples of drugs which inhibit metabolism by liver? |
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Definition
Cimetidine
ketoconazole
Isoniazide |
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Term
| What are the usual Phase I reactions? |
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Definition
- Oxidations
- Reductions
- Hydrolyses |
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Term
| What is the purpose of Phase I reactions during Drug metabolism? |
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Definition
| Phase I reactions occur.. so that Phase II reactions can occur |
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Term
| Phase II reactions consist of? |
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Definition
Conjugation of drugs or metabolites involves
- the addition of an endogenous substance (eg: Carbohydrate or sulfate)
- so that the end product is more hydrophilic so that it can be excreted.. |
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Term
| What are the compounds which are usually involved in conjugation? |
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Definition
Usually carbohydrates - Glucoronic acid
Also
- sulfates
- amino acids
or by acetylation |
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Term
Conjugated drugs are _______ secreted in the bile:
1) Actively
2) Passively |
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Definition
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Term
| Which are the factors affecting hepatic metabolism? |
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Definition
- Age
- Genetics
- Hepatic insufficiency
- Drug interactions
- Hepatic blood flow |
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Term
| How is 'genetics' involved in hepatic metabolism? |
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Definition
| The activity of N-acetyltransferase is regulated by genetic factors and influences the metabolism of procainamide, dapsone and isoniazid |
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Term
| Organ responsible for primary drug-excretion? |
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Definition
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Term
| Drug excretion follow drug decay curves which could be based on: |
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Definition
Zero order kinetics
First order kinetics |
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Term
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Definition
1) Drug excretion is not dependent on the plasma drug concentration
2) A constant AMOUNT of drug is eliminated over a given time period
3) Occurs when the elimination process is saturated.
4) Eg of such a drug is Ethanol |
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Term
| characteristics of first order kinetics: |
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Definition
1) Most drugs follow first-order kinetics
2) Elimination is concentration dependent
3) Elimination follows exponential kinetics
4) Processes necessary for absorption and excretion are not saturable
5) A constant fraction of the drug is eliminated per unit time
6) the rate of drug removal is proportional to teh plasma concentration and the concentrationof drug diminishes logarithmically with time. |
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Term
| What does clearance mean? |
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Definition
| Mathematically equivalent to the volume of blood that can be completely cleared of a drug per unit time. |
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Term
| Whenever the rate of administration exceeds the rate of excretion ________ occurs |
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Definition
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Term
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Definition
| Half life of a drug determines the dose interval necessary to obtain the desired level of drug |
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Term
| Autopharmacologic agents? |
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Definition
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Term
| Name the various classes of autocoids? |
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Definition
Histamine
Serotonin
Angiotensins
Kinins
Eicosanoids (Prostaglandins) |
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Term
Histamine found in which tissue?
a)Circulating basophils b)Tissue mast cells c)a & b
d)All mammalian tissues |
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Definition
| All mammalian tissues! But the highest concentrations are seen in Mast cells and basophils |
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Term
| Describe the process of 'bridging' on mast cells? |
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Definition
| The mast cell's surface consists of two attached IgE molecules. A specific antigen attaches itself to the two IgE molecules and triggers the release of histamine. |
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Term
| How do the levels of the compounds cAMP and cGMP influence on the release of the compound histamine from mast cells? |
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Definition
Decreased levels.. promote release of this chemical
Conversely, Beta adrenergic stimulation and glucocorticoids decrease histamine's release by increasing intracellular cAMP |
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Term
| Contents of mast-cell granules? |
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Definition
Histamines
Kallikrein
Prostaglandins
Slow reacting substance of anaphylaxis (SRS-A) |
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Term
| Locations of the various Histamine receptors?? |
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Definition
H1 - Mainly in Smooth muscle cells, Vascular ENDOTHELIAL cells, Heart, Central Nervous system
H2 - Gastric parietal cells + Vascular SMOOTH muscle cells + Neutrophils + CNS + Heart + UTERUS (All these locations are xtremely interesting)
H3 - (Nothing specific.. except lungs)
CNS + PNS + Heart + GI + Endothelial cells + LUNGS
H4 - Bone marrow and WBC |
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Term
| How do you remember the actions of the H1 and H2 receptors? |
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Definition
H1 - Asthma receptor + 'Triple response of Lewis' receptor!! ('cos located in the bronchioles of lungs and causes bronchoconstriction and also present in the skin.. and during the Lewis's reaction.. leaky capillaries.. owing to capillary vasodilation of smaller vessels!!)
H2 - Gastric ulcer receptors + Vasodilation (same as above)) |
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Term
| Acronym for H1 blocking classes of drugs??? |
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Definition
P A P P E E
Piperazines Alkylamines Piperidines Phenothiazines Ethanolamines Ethylenediamines |
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