This document discusses pharmacodynamics, which is the study of what a drug does to the body. It covers drug action, effect, and the various mechanisms of drug action including physical action, chemical action, interactions with regulatory proteins, receptors, and receptor families. It also discusses concepts like dose response curves, drug potency, efficacy, therapeutic index, synergism, and antagonism.
A power point presentation on Pharmacodynamics (what drug does to the body) suitable for undergraduate medical students beginning to study Pharmacology
Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action. Pharmacodynamics is often referred to as “what the drug does to the body”.
In order to exert their effects, drugs usually interact in a structurally specific way with a protein receptor or act on physiological processes within the body. This activates a secondary messenger system that produces a physiological effect. Drugs do not create new action but they can only modify (alter) the functions of cells or tissues in body. The drug–receptor complex initiates alterations in biochemical and/or molecular activity of a cell by a process called signal transduction.
A power point presentation on Pharmacodynamics (what drug does to the body) suitable for undergraduate medical students beginning to study Pharmacology
Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action. Pharmacodynamics is often referred to as “what the drug does to the body”.
In order to exert their effects, drugs usually interact in a structurally specific way with a protein receptor or act on physiological processes within the body. This activates a secondary messenger system that produces a physiological effect. Drugs do not create new action but they can only modify (alter) the functions of cells or tissues in body. The drug–receptor complex initiates alterations in biochemical and/or molecular activity of a cell by a process called signal transduction.
Drug Antagonism
The effect of one drug blocked (or inhibited) due to another drug is said to be antagonism. In other word, an interaction between two or more drugs that have opposite effects on the body. Drug antagonism may block or reduce effectiveness of one or more of the drugs.
e.g., atropine blocks the action of acetylcholine
Types of antagonism
1. Pharmacological antagonism: Competitive and Non-Competitive
2. Physiological antagonism
3. Chemical antagonism
Competitive Antagonism
If both the agonist and the antagonist compete for the same receptor in a reversible manner, they are said to be “competitive.” The antagonist drug interacts with the receptor and blocks it. Therefore it does not produce pharmacological action. The extent of antagonism depends on number of receptors occupied by the both drugs (agonist and antagonist), their affinity for receptors and their concentration. The increase in concentration of either one of these drugs can displace the other from receptor binding sites. Drugs interact with their receptors by weak bonds i.e. ionic bond or Hydrogen bond or Vander wal force. Hence duration of action of drug is short. Both agonist and antagonist have chemical resemblance (structural similarity).
Here's a shortly described presentation on molecular mechanism of drug action that I presented for my pharmacology course.
I tried to include everything related to this topic shortly including receptors, ion channels, carrier molecules & enzymes.
Hope it'll be helpful.
• Definition of terms associated with Adverse Drug Reactions (ADRs)
• Classification of ADRs
• Discussion on each type of ADR with examples
• Role of the Pharmacists
Drug Antagonism
The effect of one drug blocked (or inhibited) due to another drug is said to be antagonism. In other word, an interaction between two or more drugs that have opposite effects on the body. Drug antagonism may block or reduce effectiveness of one or more of the drugs.
e.g., atropine blocks the action of acetylcholine
Types of antagonism
1. Pharmacological antagonism: Competitive and Non-Competitive
2. Physiological antagonism
3. Chemical antagonism
Competitive Antagonism
If both the agonist and the antagonist compete for the same receptor in a reversible manner, they are said to be “competitive.” The antagonist drug interacts with the receptor and blocks it. Therefore it does not produce pharmacological action. The extent of antagonism depends on number of receptors occupied by the both drugs (agonist and antagonist), their affinity for receptors and their concentration. The increase in concentration of either one of these drugs can displace the other from receptor binding sites. Drugs interact with their receptors by weak bonds i.e. ionic bond or Hydrogen bond or Vander wal force. Hence duration of action of drug is short. Both agonist and antagonist have chemical resemblance (structural similarity).
Here's a shortly described presentation on molecular mechanism of drug action that I presented for my pharmacology course.
I tried to include everything related to this topic shortly including receptors, ion channels, carrier molecules & enzymes.
Hope it'll be helpful.
• Definition of terms associated with Adverse Drug Reactions (ADRs)
• Classification of ADRs
• Discussion on each type of ADR with examples
• Role of the Pharmacists
ADME: the Absorption, Distribution, Metabolism, and Excretion of DrugsRobert T Fremeau Jr PHD
Robert T. Fremeau Jr., PhD, possesses over 20 years of experience in the field of drug discovery in academic and industrial settings. As managing director of NeuroRX Consulting, Robert T. Fremeau Jr., PhD, offers consultation services to pharmaceutical and drug development companies regarding a variety of subjects, including matters associated with pharmacokinetics, the study of how the body processes drugs. Dr. Fremeau can be reached by email at rfremeau@neurorxconsulting.com.
Drug interaction final edition -- animatedAhmed Omar
this is a lecture of " drug interactions " , shows:
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-mechanisms
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hope u enjoy the lecture :)
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.
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THIS PPT INCLUDE PHARMACODYNAMICS AND THIS PPT IS VERY USEFUL FOR (MBBS,BDS ) STUDENTS ,POSTGRADUATE STUDENT (MD,MDS,Phd) STUDENTS TO UNDERSTAND PHARMACODYNAMICS.
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International Collaboration: Clear guidelines are needed for research and human trials.
Public Education: Open discussions ensure informed decisions about CRISPR.
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Defecation
Normal defecation begins with movement in the left colon, moving stool toward the anus. When stool reaches the rectum, the distention causes relaxation of the internal sphincter and an awareness of the need to defecate. At the time of defecation, the external sphincter relaxes, and abdominal muscles contract, increasing intrarectal pressure and forcing the stool out
The Valsalva maneuver exerts pressure to expel faeces through a voluntary contraction of the abdominal muscles while maintaining forced expiration against a closed airway. Patients with cardiovascular disease, glaucoma, increased intracranial pressure, or a new surgical wound are at greater risk for cardiac dysrhythmias and elevated blood pressure with the Valsalva maneuver and need to avoid straining to pass the stool.
Normal defecation is painless, resulting in passage of soft, formed stool
CONSTIPATION
Constipation is a symptom, not a disease. Improper diet, reduced fluid intake, lack of exercise, and certain medications can cause constipation. For example, patients receiving opiates for pain after surgery often require a stool softener or laxative to prevent constipation. The signs of constipation include infrequent bowel movements (less than every 3 days), difficulty passing stools, excessive straining, inability to defecate at will, and hard feaces
IMPACTION
Fecal impaction results from unrelieved constipation. It is a collection of hardened feces wedged in the rectum that a person cannot expel. In cases of severe impaction the mass extends up into the sigmoid colon.
DIARRHEA
Diarrhea is an increase in the number of stools and the passage of liquid, unformed feces. It is associated with disorders affecting digestion, absorption, and secretion in the GI tract. Intestinal contents pass through the small and large intestine too quickly to allow for the usual absorption of fluid and nutrients. Irritation within the colon results in increased mucus secretion. As a result, feces become watery, and the patient is unable to control the urge to defecate. Normally an anal bag is safe and effective in long-term treatment of patients with fecal incontinence at home, in hospice, or in the hospital. Fecal incontinence is expensive and a potentially dangerous condition in terms of contamination and risk of skin ulceration
HEMORRHOIDS
Hemorrhoids are dilated, engorged veins in the lining of the rectum. They are either external or internal.
FLATULENCE
As gas accumulates in the lumen of the intestines, the bowel wall stretches and distends (flatulence). It is a common cause of abdominal fullness, pain, and cramping. Normally intestinal gas escapes through the mouth (belching) or the anus (passing of flatus)
FECAL INCONTINENCE
Fecal incontinence is the inability to control passage of feces and gas from the anus. Incontinence harms a patient’s body image
PREPARATION AND GIVING OF LAXATIVESACCORDING TO POTTER AND PERRY,
An enema is the instillation of a solution into the rectum and sig
Medical Technology Tackles New Health Care Demand - Research Report - March 2...pchutichetpong
M Capital Group (“MCG”) predicts that with, against, despite, and even without the global pandemic, the medical technology (MedTech) industry shows signs of continuous healthy growth, driven by smaller, faster, and cheaper devices, growing demand for home-based applications, technological innovation, strategic acquisitions, investments, and SPAC listings. MCG predicts that this should reflects itself in annual growth of over 6%, well beyond 2028.
According to Chris Mouchabhani, Managing Partner at M Capital Group, “Despite all economic scenarios that one may consider, beyond overall economic shocks, medical technology should remain one of the most promising and robust sectors over the short to medium term and well beyond 2028.”
There is a movement towards home-based care for the elderly, next generation scanning and MRI devices, wearable technology, artificial intelligence incorporation, and online connectivity. Experts also see a focus on predictive, preventive, personalized, participatory, and precision medicine, with rising levels of integration of home care and technological innovation.
The average cost of treatment has been rising across the board, creating additional financial burdens to governments, healthcare providers and insurance companies. According to MCG, cost-per-inpatient-stay in the United States alone rose on average annually by over 13% between 2014 to 2021, leading MedTech to focus research efforts on optimized medical equipment at lower price points, whilst emphasizing portability and ease of use. Namely, 46% of the 1,008 medical technology companies in the 2021 MedTech Innovator (“MTI”) database are focusing on prevention, wellness, detection, or diagnosis, signaling a clear push for preventive care to also tackle costs.
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One of the most developed cities of India, the city of Chennai is the capital of Tamilnadu and many people from different parts of India come here to earn their bread and butter. Being a metropolitan, the city is filled with towering building and beaches but the sad part as with almost every Indian city
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Alongside the 77th World Health Assembly in Geneva on 28 May 2024, we launched the second version of our Index, allowing us to track progress and give new insights into what needs to be done to keep populations healthier for longer.
The speakers included:
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Dr Hans Groth, Chairman of the Board, World Demographic & Ageing Forum
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Dr Natasha Azzopardi Muscat, Director, Country Health Policies and Systems Division, World Health Organisation EURO
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Dr Shyam Bishen, Head, Centre for Health and Healthcare and Member of the Executive Committee, World Economic Forum
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2. It covers all the aspects relating to “What a drug
does to the body”
It is the study of the mechanism by which the drug
produces a response.
3. Action: How and Where the effect is produced is
called as Action.
Effect: The type of response producing by drug.
4. TYPES OF DRUG ACTION
EFFECT (Type of responses):-
1.Stimulation-
it is selective enhancement of the
level of activity of specialized cells.
Eg; adrenaline stimulate the heart.
2.Inhibition/Depression-
it is selective diminution of activity
of specialized cells. Eg: quinidine
depresses heart.
5. • 3.Replacement-
This refers to the use of natural
metabolites, hormones in deficiency
states. Eg; iron in anaemia.
• 4.Irritation-
This refers a nonselective, often
noxious effect and is particularly
applied to less specialized cells. Eg:
counterirritants increase blood flow
to the site.
7. Mechanism of Drug Action:
A drug may produce its effects through various
mechanisms:
8. 1- Physical action:
Osmosis:
Drug retains water by osmosis as osmotic diuretics (Mannitol) and osmotic
purgatives (Lactulose).
Adsorption:
Drug adsorbs diverse substances including toxins and fluid on its
surface thereby inactivating them (activated charcoal).
9. 2- Chemical action:
- Antacids neutralize gastric acidity (e.g. NaHCO3)
- Chelating agents form biologically inactive complex
with other substances
10. 3- Regulatory Proteins (Body Control systems):
- Enzymes:
Drugs may inhibit or activate certain enzymes.
-Carrier Molecules:
Drugs may increase their synthesis or block their recognition site.
-Ion Channels:
Drugs may open ion channels by acting on specific receptor which forms the
channel or drugs may physically close the channel
11. Receptors:
Responses to drug-receptor interaction can be as Agonist
(substance binds and activates the receptor) or
Antagonist (substance blocks the receptor.)
12. Receptors are macromolecules
Most are proteins
Present either on the cell surface, cytoplasm or in
the nucleus
13. Drug(D) +Receptor® Drug receptor complex
Response
Drug receptor interaction:-
1. Selectivity:- Degree of complimentary co relation between
drug and receptor.
Ex:- Adrenaline Selectivity for α, ß Receptor
2. Affinity:- Ability of drug to get bound to the receptor.
3. Intrinsic activity (IA) or Efficacy:- Ability of drug to produce a
pharmacological response after making the drug receptor
complex.
15. RECEPTOR FAMILIES
Four types of receptors families
1. Receptors with intrinsic ion channels.
2.G-protien coupled receptor
3. Enzymatic receptors
4 intracellular receptor
16. Receptors with intrinsic ion channels
-located on the cell surface
-they enclose ion selective channels for
Na,K,Ca,Cl.
-when an agonist is bound to these receptors they
convey signals.
Eg: nicotinic cholinergic receptors
17. 2.G-protien coupled receptor
located on the cell membrane
G protein is a connecting link between receptor and
effector systems ,like enzymes, carrier molecules
etc.
They are called so because of their link with GDP
AND GTP
18. 3.intracellular receptor
Present either in cytoplasm or nucleus of the cell.
Vit A ,corticosteroids etc act through these
receptors.
4.Enzymatic receptors
These are enzyme molecules themselves
Eg: tyrosine protein kinase.
19. SPECIAL TYPE OF RECEPTORS
SPARE RECEPTORS
Even when a receptor is blocked by irreversible
blocker ,an agonist is still capable of producing
undiminished maximum response.
Eg: if beta adrenergic receptors are blocked
irreversibly and then adrenaline is pushed , there is
still production of an undiminished maximum
inotropic response.
20. SILENT RECEPTORS
A drug when bound to such receptors, exhibits no
pharmacological response.
Eg: silent tissue receptors.
PRESYNAPTIC RECEPTORS
Usually found in axonal terminals and on cell
bodies of neurons.
If these receptors are stimulated , usually there
occurs a inhibitory response.
It is due to inhibition of release of excitatory
neurotransmitter.
21. REGULATION OF RECEPTORS
Receptor down regulation: or Desensitization
Prolonged use of agonist
Receptor number and sensitivity
Drug effect
Ex: Chronic use of salbutamol down regulates ß2
adrenergic receptors
22. Receptor up regulation: or Super sensitivity
Prolonged use of antagonist
Receptor number and sensitivity
Drug effect
Eg:- if timolol is stopped after prolong use, produce
withdrawal symptoms. Rise iop.
23. DOSE RESPONSE CURVE
When a drug is administered, it produces a response and
this response shows alteration with change in dose.
The change can be plotted with dose as abscissa and
response as ordinate.
The resulting curve is known as DOSE RESPONSE
CURVE.
24.
25. GRADED RESPONSE
The dose response curve rises steeply at first, but after
that it become steady as the dose is increased.
Curve is popularly known as hyperbolic or exponential
curve.
Such a curve can be shown by plotting dose against
percent response.
26. QUANTAL RESPONSE
Initially no appreciable response until a particular
threshold is obtained.
Thereafter the curve rises steeply until a maximum
response is attained.
But after this there is no appreciable change in the curve
even with increased dose.
This is called sigmoid or s shaped curve (log dose is
plotted against percent data)
27.
28. Potency
It is used to indicate the amount of drug required to
produce a specific response.
EFFICACY
Efficacy is the maximal effect produced by a drug . This is
important to know when deciding between two drugs that have
similar action. For example, two antibiotics may effectively kill
the same organism, but one may take more doses than another,
making the other more effective.
29. Drug A is more potent than B
Drug A is less effective than B
30. Median effective dose(ED50 ).
Is a dose of the drug that gives a response equals to 50% of the
maximal response.
Median lethal dose(LD50 ).
Is the dose of a drug required to produce
toxicity in 50 % of patients.
31. THERAPEUTIC INDEX(TI)
It is a measure of the relative safety of a drug for a
particular treatment.
Therapeutic index = LD50 / ED50
Large value - a wide margin of safety. Eg:Penicillin
Small value - a narrow margin of safety Eg:
warfarin
32. COMBINED EFFECT OF DRUGS
When two or more drugs are given simultaneously or
directly after each other, they may be either indifferent to
each other or exhibit synergism or antagonism
33. SYNERGISM
Action of one drug is increased by the other.
Additive:
combined effect of two drugs acting by same mechanism
Aspirin codiene
PG PG
Analgesic+ Analgesic+
+ +
34. Synergism (Supra additive):- (1+1=3)
The combined effect of two drug effect is higher than either
individual effect.
Ex:-
1.Sulfamethaxazole+ Trimethoprim
2. Levodopa + Carbidopa.
35. ANTAGONISM
When one drug decreases or abolishes the action of another.
Effect of drug A+ B < Effect of drug A+ Effect of drug B
Types :
Physical antagonism
Chemical antagonist.
Physiological antagonist.
Pharmacological antagonist.
36. 1) Physical Antagonism
Based on physical property.
Examples
Charcoal adsorbs alkaloids and can prevent their
absorption used in alkaloid poisoning.
37. 2) Chemical Antagonism
Two drugs react chemically and form an inactive
product.
Examples
KMnO4 oxidizes alkaloid used for gastric lavage in
poisoning.
38. 3) Physiological Antagonism
Two drugs acting on different receptors by different
mechanism, have opposite effect on the same
physiological function.
Glucagon & insulin on blood sugar.
39. 4) Pharmacological Antagonism
Two drugs compete for the same receptor.
The antagonist partially or completely
prevents the pharmacological agonist effect.
Pharmacological antagonist
Competitive
• Reversible
Non-competitive
• Irreversible
40. Competitive Antagonist
The antagonist dissociates rapidly from the receptor.
The antagonist effect can be overcome by increasing the
agonist concentration.
e.g. morphine & naloxone
41. Noncompetitive Antagonist
The antagonist dissociates very slowly or not at all from
the receptor .
The action of antagonist cannot be overcome by
increasing the agonist concentration .
42. Dose
Appropriate amount of drug required to produce a
desired pharmacological action.
LOADING DOSE
Dose required to achieve a target concentration rapidly.
MAINTENANCE DOSE
used to retain the target level by balancing the
elimination.
Loading dose of doxycycline is 200 mg and maintenance
dose is 100 mg/day.