Intro Flashcards
Prescription highlight?
Highlight of prescribing information
Contain FPI
FPI?
Full prescribing information
Contain detailed info
Pharmacology?
Pharmacognosy, kinetic, dynamic, therapeutic and toxicology
Application of clinical pharmacology?
Clinical trials
NDA
New drug application 💌
Pharmacogenetic?
Pharmacogenomics is the study of how genes affect a person’s response to drugs. This field combines pharmacology (the science of drugs) and genomics (the study of genes and their functions)
Drug exposure & response?
Exposure: measure of amount of drug concentration in plasma or other biological fluid (Cmax,Cmin, Css, AUC)
Response: drug pharmacological effect
Toxicokinetics vs clinical toxicology?
Toxicokinetics: use of pharmacokinetics in drug safety evaluation study in drug design
C.t: study of adverse effects of drug and toxic substances in body 👁️
Method of sampling of biologic specimen?
- Inversive: sampling blood , spinal fluid, tissue biopsy, synovial fluid etc
- non inversive: without surgery: sampling urine , feces , expired air etc
Serum vs plasma
Serum is the liquid that remains after the clotting of blood. Whereas, plasma is the liquid that remains when anticoagulant is added to prevent clotting
Serum= Plasma - clotting factors
plasma drug concentration time curve
Obtain by Drug concentration in plasma sample taken at different times interval
Plasma level 🎚️ vs time curve ⏱️
TDM
Therapeutic drug monitoring
Branch of clinical pharmacology
Measurements of specific drug at designated interval to maintain a constant concentration in patient blood stream
Therapeutic index ☝️
Ratio between dosage of drug causing toxic and therapeutic effect
Lethal or toxic dose (TD 50) TI ==-------------------------------------------------
Medium effective dose (ED 50)
Td50 50% toxicity
Ed 50 % therapeutic effective
Therapeutic window
Range of dosage that cause therapeutic effect without causing significant side effects
TW = MEC:MTC
AUC
AUC (areas under curve)is the total integrated area under the plasma drug concentration–time curve. It expresses the total amount of drug that comes into systemic circulation .
NTI ?
Narrow therapeutic index (NTI) drugs are defined as those drugs where small differences in dose or blood concentration may lead to dose and blood concentration dependent, serious therapeutic failures or adverse drug reactions.
Smaller difference in dosage cause serious therapeutic adverse drug reaction
NTI drug example?
narrow therapeutic index drugs: aminoglycosides, ciclosporin, carbamazepine, digoxin, digitoxin, flecainide, lithium, phenytoin, phenobarbital, rifampicin, theophylline and warfarin.
TDM?
Therapeutic drug monitoring (TDM) is testing that measures the amount of certain medicines in your blood.
It is done to make sure the amount of medicine you are taking is both safe and effective
When is TDM done?
Therapeutic drug monitoring (TDM) should be performed when the patient has achieved steady-state concentration, has changed drug therapy, or has had a change in response to treatment (eg, toxicity).
When is TDM done?
Therapeutic drug monitoring (TDM) should be performed when the patient has achieved steady-state concentration, has changed drug therapy, or has had a change in response to treatment (eg, toxicity).
PDC?
Drug concentration” is derived by collecting a blood sample at any time after drug administration and measuring the amount of a drug in a given volume of blood plasma of the sample. The measured drug concentration is generally known as “plasma concentration.”
Wide therapeutic index drugs example?
Ibuprofen
Calcium channel blockers
NASID
MEC
Minimum effective concentration (MEC) is the minimum plasma concentration of a drug needed to achieve sufficient drug concentration at the receptors to produce the desired pharmacologic response, if drug molecules in plasma are in equilibrium with drug molecules in the various tissues
maximum effective concentration?
maximum concentration The peak concentration that a drug achieves in a specified compartment after the drug has been administrated and before administration of a second dose. Cmax is the opposite of Cmin—which is the minimum (or trough) concentration that a drug achieves after dosing
(MTC)
Maximum Safe Concentration (MSC): Also called as minimum toxic concentration (MTC) It is the concentration of drug in plasma above which adverse or unwanted effects are precipitated. Concentration of drug above MSC is said to be in the toxic level.
What is onset of action?
The length of time it takes for a medicine to start to work.
Time required to achieve MEC
Onset (how quickly they act)
Peak (how long it takes to achieve maximum impact)
Duration (how long they last before they wear off)
Cmax
Cmax is the maximum (or peak) serum concentration that a drug achieves in a specified compartment or test area of the body after the drug has been administered and before the administration of a second dose. It is a standard measurement in pharmacokinetics
What is T max and Cmax of a drug?
Definition: The time it takes for a drug to reach the maximum concentration (Cmax) after administration of a drug that needs to be absorbed (e.g. an oral drug).
Cmax is the highest concentration of a drug in the blood, cerebrospinal fluid, or target organ after a dose is given
Bioavailability
Bioavailability refers to the extent and rate at which the active moiety (drug or metabolite) enters systemic circulation, thereby accessing the site of action.
Type of bioavailability
- Absolute Bioavailability: When the drug is administered through the intravenous route, the bioavailability of the drug achieved will be 100%. If the reference standard is an IV dose, it is referred to as Absolute Bioavailability.
Route of administration
oral
-IM (intramuscular)
-IV (intravenous)
- Relative Bioavailability:
It is the bioavailability of the drug when obtained and it is compared with a reference standard.
If the reference standard is any other dosage form than the IV dose, it is referred to as Relative bioavailability. - Bioequivalence:
When two or more than two drugs that are having the same Composition, when administered inside the body they will show statistically the same desired outcomes for patients over a given period of time. - Dosage form: The rate of bioavailability (from
higher to lower) of drugs in the different dosage
forms is as follows
Solution Suspension Powder Tablets Capsules
Solutions are better absorbed than suspension than
powder than tablet than capsules. - Manufacturing variables: Various additives such
as Diluent, Fillers, Absorbers, Binding agents are
added to make the particular dosage form. A change
in concentration of the binders will change the
disintegration time of the granules. As there is an
increase in disintegration time, there will be a
decrease in the bioavailability of drugs. The addition
of diluent, i.e, Calcium Phosphate in Tetracycline
capsules will change the dissolution rate and hence
bioavailability of the drug will be changed. - Disintegration rate: By maintaining the
concentration of filler inside the particular dosage
form, the rate of disintegration can be maintained
which in turn will affect the bioavailability. - Dissolution rate: Higher the dissolution rate of the
drug, the more is the bioavailability of the drug. - Biological Factors:
A) GIT motility: When GIT motility increases, there
will be a decrease in the bioavailability of the drug as
well as a decrease in the rate of dissolution.
B) First-pass metabolism: Drugs that are
administered through the sublingual route
(Nitroglycerine tablets). When drugs are taken orally,
they will directly go to the hepatic portal system
4 - Disintegration rate: By maintaining the
concentration of filler inside the particular dosage
form, the rate of disintegration can be maintained
which in turn will affect the bioavailability. - Dissolution rate: Higher the dissolution rate of the
drug, the more is the bioavailability of the drug. - Biological Factors:
A) GIT motility: When GIT motility increases, there
will be a decrease in the bioavailability of the drug as
well as a decrease in the rate of dissolution.
B) First-passs metabolism: Drugs that are
administered through the sublingual route
(Nitroglycerine tablets). When drugs are taken orally,
they will directly go to the hepatic portal system
(liver) which is the site for metabolism, drugs get
metabolized in the liver rapidly and hence there will
be no or negligible bioavailability.
C) GIT flora: Microorganisms that are present in our
GIT, higher antibiotics absorb microorganisms that
are present in GIT, as a result, the functioning of the
microorganism will get disturbed and as a result
bioavailability of the drug will be decreased.
D) Disease status: If the patient is suffering from
renal failure, and was previously given higher class
drugs, there will be a decrease in the rate of
absorption of drugs due to the resistance developed
and hence decreasing the bioavailability of drugs.
various factors affecting Bioavailability
- Physiochemical Properties
A) State of drug: Drugs in solution form or
suspension are better absorbed compared to solid
dosage form as they require time for dissolution as
well as absorption.
B) Particle size: Decrease in particle size, increases
surface area and hence solubility of drug increases which increase in absorption, dissolution increases and in turn bioavailability increases.
C) pKa value and state of ionization: Non-ionised drugs are better absorbed than ionized drugs depending upon the surrounding ph and pKa value of the drug.
D) Partition Coefficient: It is the ratio of solubility of the drug in a non-aqueous solvent to the ratio of solubility of the drug in an aqueous solvent. As there is an increase in the partition coefficient of drugs, there will be an increase in the bioavailability of drugs.
E) Route of administration: When the drug is administered through the parenteral route, bioavailability achieved is 100 percent. When the drug is administered through the oral route, bioavailability decreases while the drug administered through inhalation or sublingual route the bioavailability increases.
F) Plasma protein binding: When the drug is bound to the plasma protein, it will increase the therapeutic effect of the drug, i.e, duration of action of the drug
