A Powerpoint presentation on drugs excretion and elimination suitable for UG medical students. This ppt is already presented to my students in one of the theory classes.
Pharmacokinetics is the study of the movement of drug molecules in the body. It includes absorption, distribution, metabolism, and excretion of drugs. Pharmacokinetics is the study of what happens to drugs once they enter the body (the movement of the drugs into, within, and out of the body). For a drug to produce its specific response, it should be present in adequate concentrations at the site of action. This depends on various factors apart from the dose.
Four pharmacokinetic properties determine the onset, intensity, and the duration of drug action (Figure 1.6.1):
• Absorption: First, absorption from the site of administration permits entry of the drug (either directly or indirectly) into plasma.
• Distribution: Second, the drug may then reversibly leave the bloodstream and distribute it into the interstitial and intracellular fluids.
• Metabolism: Third, the drug may be biotransformed by metabolism by the liver or other tissues.
• Elimination: Finally, the drug and its metabolites are eliminated from the body in urine, bile, or feces.
In short, pharmacokinetics means what the body does to the drug.
Presentation made by Dr. Resu Neha Reddy, M.D. Pharmacology, Osmania Medical College. The presentation is about excretion of the drugs by kidneys, liver and other routes and kinetics of elimination, which includes zero, first and mixed (Michaelis - Menton equation) order kinetics. It also includes information regarding clearance, half-life, loading dose, maintenance dose and fixed dose drug combinations.
A Powerpoint presentation on drugs excretion and elimination suitable for UG medical students. This ppt is already presented to my students in one of the theory classes.
Pharmacokinetics is the study of the movement of drug molecules in the body. It includes absorption, distribution, metabolism, and excretion of drugs. Pharmacokinetics is the study of what happens to drugs once they enter the body (the movement of the drugs into, within, and out of the body). For a drug to produce its specific response, it should be present in adequate concentrations at the site of action. This depends on various factors apart from the dose.
Four pharmacokinetic properties determine the onset, intensity, and the duration of drug action (Figure 1.6.1):
• Absorption: First, absorption from the site of administration permits entry of the drug (either directly or indirectly) into plasma.
• Distribution: Second, the drug may then reversibly leave the bloodstream and distribute it into the interstitial and intracellular fluids.
• Metabolism: Third, the drug may be biotransformed by metabolism by the liver or other tissues.
• Elimination: Finally, the drug and its metabolites are eliminated from the body in urine, bile, or feces.
In short, pharmacokinetics means what the body does to the drug.
Presentation made by Dr. Resu Neha Reddy, M.D. Pharmacology, Osmania Medical College. The presentation is about excretion of the drugs by kidneys, liver and other routes and kinetics of elimination, which includes zero, first and mixed (Michaelis - Menton equation) order kinetics. It also includes information regarding clearance, half-life, loading dose, maintenance dose and fixed dose drug combinations.
The slides describe concept of distribution, Volume of distribution, factors affecting volume of distribution and the barriers to distribution. Blood brain barrier and placental barrier.
The slides describe concept of distribution, Volume of distribution, factors affecting volume of distribution and the barriers to distribution. Blood brain barrier and placental barrier.
c ADVANCED BIOPHARMACEUTICS AND PHARMACOKINETICS PRESENTATION BY- NARAYAN R K...NarayanRajaramkote
INTRODUCTION
Excretion is defined as the process whereby drugs and/or their metabolites are irreversibly transferred from internal to external environment.
Excretion of unchanged or intact drug is important in the termination of its pharmacological action.
The principal organs of excretion are kidneys. Excretion of drug by kidneys is called as renal excretion.
Excretion by organs other than kidneys such as lungs, biliary system, intestine, salivary glands and sweat glands is known as nonrenal excretion. Almost all drugs and their metabolites are excreted by the kidneys to some extent or the other.
Some drugs such as gentamicin are exclusively eliminated by renal route only.
Agents that are excreted in urine are –
1. Water-soluble.
2. Non-volatile.
3. Small in molecular size (less than 500 Daltons).
4. The ones that are metabolised slowly
The basic functional unit of kidney involved in excretion is the nephron. Each kidney comprises of one million nephrons.
Each nephron is made up of the glomerulus, the proximal tubule, the loop of Henle, the distal tubule and the collecting tubule.
Glomerular Filtration :
Glomerular filtration is a non-selective, unidirectional process whereby most compounds, ionised or unionised, are filtered except those that are bound to plasma proteins or blood cells and thus behave as macromolecules.
The driving force for filtration through the glomerulus is the hydrostatic pressure of the blood flowing in the capillaries. Out of the 25% of cardiac output or 1.2 litres of blood/min that goes to the kidneys via renal artery, only 10% or 120 to 130 ml/min is filtered through the glomeruli, the rate being called as the glomerular filtration rate (GFR).
The GFR can be determined by an agent that is excreted exclusively by filtration and is neither secreted nor reabsorbed in the tubules. The excretion rate value of such an agent is 120 to 130 ml/min. Creatinine, inulin, mannitol and sodium thiosulphate are used to estimate GFR of which the former two are widely used to estimate renal function.
Pharmacokinetics - drug absorption, drug distribution, drug metabolism, drug ...http://neigrihms.gov.in/
A power point presentation on general aspects of Pharmacokinetics suitable for undergraduate medical students beginning to study Pharmacology. Also suitable for Post Graduate students of Pharmacology and Pharmaceutical Sciences.
Pharmacokinetics (PK) is the study of how the body interacts with administered substances for the entire duration of exposure (medications for the sake of this article). This is closely related to but distinctly different from pharmacodynamics, which examines the drug’s effect on the body more closely. The four main parameters generally examined by this field include absorption, distribution, metabolism, and excretion (ADME). Wielding an understanding of these processes allows practitioners the flexibility to prescribe and administer medications that will provide the greatest benefit at the lowest risk and allow them to make adjustments as necessary, given the varied physiology and lifestyles of patients.
When a provider prescribes medication, it is with the ultimate goal of a therapeutic outcome while minimizing adverse reactions. A thorough understanding of pharmacokinetics is essential in building treatment plans involving medications. Pharmacokinetics, as a field, attempts to summarize the movement of drugs throughout the body and the actions of the body on the drug. By using the above terms, theories, and equations, practitioners can better estimate the locations and concentrations of a drug in different areas of the body.
The appropriate concentration needed to obtain the desired effect and the amount needed for a higher chance of adverse reactions is determined through laboratory testing. Using the equations given above, a clinician can easily estimate safe medication dosing over a period of time and how long it will take for a medication to leave a patient’s system. These are, however, statistically-based estimations, influenced by differences in the drug dosage form and patient pathophysiology. This is why a deep understanding of these concepts is essential in medical practice so that improvisation is possible when the clinical situation requires it.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
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1. Dr. RAGHU PRASADA M S
MBBS,MD
ASSISTANT PROFESSOR
DEPT. OF PHARMACOLOGY
SSIMS & RC.
2. Excretion is a process whereby drugs are transferred from the
internal to the external environment
Excretion, along with metabolism and tissue redistribution, is
important in determining both the duration of drug action and
the rate of drug elimination.
Principal organs involved
Kidneys, Lungs,
Biliary system, Intestines
Saliva and Milk.
EXCRETION OF DRUGS
3.
4. Kidney is the primary organ of removal for most drugs
especially for those that are water soluble and not
volatile.
The three principal processes that determine the
urinary excretion of a drug
glomerular filtration,
tubular secretion, and
tubular reabsorption (mostly passive back-diffusion)
5. The ultrastructure of the glomerular capillary wall is such that it
permits a high degree of fluid filtration while restricting the
passage of compounds having relatively large molecular weights.
This selective filtration is important in that it prevents the
filtration of plasma proteins (e.g., albumin) that are important for
maintaining an osmotic gradient in the vasculature and thus
plasma volume.
Several factors, including molecular size, charge, and shape,
influence the glomerular filtration of large molecules.
All unbound drugs will be filtered as long as their molecular size,
charge, and shape are not excessively large.
6. Urinary excretion of drugs (i.e., weak electrolytes) is the
extent to which substances diffuse back across the tubular
membranes and reenter the circulation.
The movement of drugs is favored from the tubular lumen to
blood, partly because of the reabsorption of water
The concentration gradient thus established will facilitate
movement of the drug out of the tubular lumen, given that
the lipid solubility and ionization of the drug are appropriate.
The pH of the urine (usually between 4.5 and 8) can markedly
affect the rate of passive back-diffusion.
Acidification increases reabsorption (or decreases
elimination) of weak acids, such as salicylates, and decreases
reabsorption (or promotes elimination) of weak bases, such
as amphetamines.
7. A number of drugs can serve as substrates for the
two active secretory systems in the PCT
Actively transfer drugs from blood to luminal fluid,
are independent of each other; one secretes organic
anions, and the other secretes organic cations.
The secretory capacity of both the organic anion and
organic cation secretory systems can be saturated at
high drug concentrations.
Each drug will have its own characteristic maximum
rate of secretion (transport maximum,Tm).
8. Organic Anion Transport Organic Cation Transport
Acetazolamide Acetylcholine
Bile salts Atropine
Hydrochlorothiazide Cimetidine
Furosemide Dopamine
Indomethacin Epinephrine
Penicillin G Morphine
Prostaglandins Neostigmine
Salicylate Quinine
9. Some substances filtered at the glomerulus are reabsorbed by
active transport systems found primarily in the proximal
tubules.
Active reabsorption is particularly important for endogenous
substances, such as ions, glucose, and amino acids, although
a small number of drugs also may be actively reabsorbed.
The probable location of the active transport system is on the
luminal side of the proximal cell membrane.
10. The rate of urinary drug excretion will depend on the
drug’s volume of distribution, its degree of protein
binding, and the following renal factors:
1. Glomerular filtration rate
2. Tubular fluid pH
3. Extent of back-diffusion of the unionized form
4. Extent of active tubular secretion of the compound
5. Possibly, extent of active tubular reabsorption
11. Bile flow and composition depend on the secretory activity
of the hepatic cells that line the biliary canaliculi.
As the bile flows through the biliary system of ducts, its
composition can be modified in the ductules and ducts by
the processes of reabsorption and secretion, especially of
electrolytes and water.
For example, osmotically active compounds, including bile
acids, transported into the bile promote the passive
movement of fluid into the duct lumen.
12. Hence, drugs with molecular weights lower than those of most
protein molecules readily reach the hepatic extracellular fluid
from the plasma.
Group A - concentration in bile and plasma are almost identical
(bile–plasma ratio of 1).
Ex. Glucose, and ions such as Na, K, and Cl.
Group B - ratio of bile to blood is much greater than 1, usually
10 to 1,000.
Ex. bile salts, bilirubin glucuronide, procainamide
Group C - ratio of bile to blood is less than 1, for
Ex. insulin, sucrose, and proteins.
Biliary Excretion
13. The physicochemical properties of most drugs are sufficiently
favorable for passive intestinal absorption that the compound will
reenter the blood that perfuses the intestine and again be carried
to the liver.
Such recycling may continue (enterohepatic cycle or circulation)
until the drug either undergoes metabolic changes in the liver, is
excreted by the kidneys, or both.
This process permits the conservation of such important
endogenous substances as the bile acids, vitamins D3 and B12, folic
acid, and estrogens
ENTEROHEPATIC CIRCULATION
16. Any volatile material, irrespective of its route of administration, has
the potential for pulmonary excretion. Gases and other volatile
substances that enter the body primarily through the respiratory tract
can be expected to be excreted by this route.
No specialized transport systems are involved in the loss of substances
in expired air; simple diffusion across cell membranes is predominant.
The rate of loss of gases is not constant; it depends on the rate of
respiration and pulmonary blood flow.
The degree of solubility of a gas in blood also will affect the rate of gas
loss.
Gases such as nitrous oxide, which are not very soluble in blood, will
be excreted rapidly, that is, almost at the rate at which the blood
delivers the drug to the lungs.
17. Sweat and Saliva
Minor importance for most drugs.
Mainly depends on the diffusion of the un-ionized lipid-soluble form of
the drug across the epithelial cells of the glands.
Thus, the pKa of the drug and the pH of the individual secretion
formed in the glands are important determinants of the total quantity
of drug appearing in the particular body fluid.
Lipid-insoluble compounds, such as urea and glycerol, enter saliva and
sweat at rates proportional to their molecular weight, presumably
because of filtration through the aqueous channels in the secretory cell
membrane.
18. The ultimate concentration of the individual compound in
milk will depend on many factors, including the amount of
drug in the maternal blood, its lipid solubility, its degree of
ionization, and the extent of its active excretion.
The physicochemical properties that govern the excretion of
drugs into saliva and sweat also apply to the passage of drugs
into milk.
Since milk is more acidic (pH 6.5) than plasma, basic
compounds (e.g., alkaloids, such as morphine and codeine)
may be somewhat more concentrated in this fluid.
In general, a high maternal plasma protein binding of drug will
be associated with a low milk concentration.
A highly lipid-soluble drug should accumulate in milk fat.
19. Enzymatic elimination of drugs primarily First Order
Kinetics (Michaelis-Menton)
Elimination half life t 1/2 = 0.693/k
Elimination is dependent upon concentration, but
almost 97% will be eliminated after 5 half-lives
Initial concentration 1 mg%
One half life 0.5 mg%
Two half lives 0.25 mg%
Three half lives 0.125 mg%
Four half lives 0.0625 mg%
Five half lives 0.03125 mg%
or 0.96875 mg% (97%) eliminated
20.
21. First Order Elimination
[drug] decreases
exponentially w/ time
Rate of elimination is
proportional to [drug]
Plot of log [drug] or ln[drug]
vs. time are linear
t 1/2 is constant regardless
of [drug]
Zero Order Elimination
[drug] decreases linearly
with time
Rate of elimination is
constant
Rate of elimination is
independent of [drug]
No true t 1/2
22. Half-life is the time taken for
the drug concentration to fall to
half its original value
The elimination rate constant
(k) is the fraction of drug in the
body which is removed per unit
time.
23. Steady-state occurs after a drug has been given for
approximately five elimination half-lives.
At steady-state the rate of drug administration equals
the rate of elimination and plasma concentration -
time curves found after each dose should be
approximately superimposable.
24.
25. Ability of organs of elimination (e.g. kidney, liver) to
“clear” drug from the bloodstream.
Volume of fluid which is completely cleared of drug per
unit time. Units are in L/hr or L/hr/kg
Pharmacokinetic term used in determination of
maintenance doses.
Volume of blood in a defined region of the body that is
cleared of a drug in a unit time.
Clearance is a more useful concept in reality than t 1/2 or
kel since it takes into account blood flow rate.
Clearance varies with body weight.
Also varies with degree of protein binding
26. Dose rate = target Cpss *CL/F
Maintenance dose will be in mg/hr so for total daily dose
will need multiplying by 24
Rate of drug elimination=(Vmax)(C)/Km+C
C-plasma concentration, Vmax-maximum rate of drug
elimination, Km=plasma concentration
Maintenance Dose = CL x (Steady State plasma
concentration)CpSSav
CpSSav is the target average steady state drug
concentration
27. VD is a theoretical Volume and determines the loading
dose.
Clearance is a constant and determines the
maintenance dose.
CL = k VD.
CL and VD are independent variables.
k is a dependent variable.
F-bioavailability
Volume of Distribution = Dose_______
Plasma Concentration
28. An established relationship between
concentration and response or toxicity
A sensitive and specific assay
An assay that is relatively easy to perform
A narrow therapeutic range
A need to enhance response/prevent
toxicity