Matabolism of drugs in Humans
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The document discusses drug metabolism. It defines drug metabolism as the chemical processing of drugs in the body, which can result in inactive or active substances. The main site of drug metabolism is the liver, where enzymes act on drugs. Cytochrome P-450 enzymes are primarily involved in liver drug metabolism and their levels control the rate of metabolism for many drugs. The document outlines the enzyme systems involved in Phase I and Phase II drug metabolism and factors that can affect drug metabolism rates such as inhibitors, stimulators, age, sex, species, genetics, and body temperature.
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Cytochrome P450 enzymes (CYP450) play an important role in metabolizing drugs and other xenobiotic substances. There are many CYP450 isoenzymes, with CYP1A2, CYP2D6, CYP2C9, CYP2C19, and CYP3A4 being the most clinically significant in humans. These isoenzymes metabolize many psychiatric drugs and can be induced or inhibited by other drugs, foods, or substances, leading to potential drug-drug interactions. Careful consideration of a patient's complete medication regimen and lifestyle factors is important when prescribing drugs metabolized by CYP450 enzymes.
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1. Pharmacokinetics describes what the body does to a drug, including absorption, distribution, metabolism and excretion.
2. Absorption is the process by which a drug enters the body through various routes of administration and is affected by characteristics like molecular size, lipid solubility, and ionization.
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The document discusses drug metabolism and pharmacokinetics. It describes how drugs are absorbed, distributed, metabolized by the liver, and excreted from the body. Drug metabolism is important for nurses to understand as it influences toxicity, effectiveness, and interactions. Metabolism can be affected by age, nutrition status, and competition between drugs. The goal is to maximize drug benefits while minimizing harm.
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This document summarizes factors that affect drug metabolism. It discusses how drug metabolism occurs primarily in the liver through enzymatic and non-enzymatic processes. The key metabolic enzymes are microsomal and nonmicrosomal enzymes. Metabolism can inactivate drugs, produce active metabolites, or activate prodrugs. Factors that influence metabolism include chemical factors like enzyme induction/inhibition, biological factors like age, sex, diet; and physicochemical properties of drugs. Specifically, it notes how induction increases and inhibition decreases metabolic rates, and how rates vary between species, strains, ages and sexes.
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Metabolism is essential for eliminating drugs and other foreign substances from the body. Phase I metabolism makes compounds more polar through reactions like oxidation and hydrolysis. Phase II metabolism further increases polarity through conjugation. The liver is the primary site of metabolism, with cytochrome P450 enzymes performing many Phase I reactions. Metabolism inactivates most compounds but can also activate prodrugs. Factors like induction, inhibition, disease, age, sex and genetics can impact an individual's drug metabolism. Proper metabolism and excretion of compounds and their metabolites terminates their biological activity.
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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.
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1. Metabolism and excretion are important processes that determine the duration and intensity of a drug's effects in the body. Metabolism involves chemical alteration of drugs through phase I and phase II reactions, while excretion removes drugs and metabolites from the body through renal, hepatic, pulmonary and other routes.
2. Factors like age, diet, diseases, genetic factors and simultaneous administration of other drugs can influence drug metabolism by inducing or inhibiting drug-metabolizing enzymes. Metabolism can convert drugs to active, inactive or less active forms.
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The document discusses biotransformation, which is the biochemical alteration of drugs inside the body. The main site of biotransformation is the liver, with other sites including the kidneys, lungs, intestine, and skin. Biotransformation makes drugs more polar, water soluble, and less lipid soluble to promote excretion. It can convert active drugs into inactive metabolites or active metabolites. The two main phases are phase I reactions, which use oxidation, reduction, and hydrolysis to introduce or remove functional groups, and phase II reactions, which produce non-toxic conjugates through glucoronidation, acetylation, methylation, and other conjugation reactions. Factors that can influence biotransformation include patient factors like age and genetics
Drug interactions by amna samin
The document discusses drug interactions, defining it as when the pharmacological activity of one drug is altered by the concomitant use of another drug. It describes the main types of interactions as pharmacokinetic, involving effects on absorption, distribution, metabolism and excretion, and pharmacodynamic, involving effects on pharmacological activity. The key mechanisms of pharmacokinetic interactions are induction or inhibition of drug-metabolizing enzymes and displacement from plasma protein binding. Food and herbs can also cause interactions.
Drug metabolism or Biotransformation
Drugs and other foreign substances that enter the body undergo a process of biotransformation or metabolism within the body. This involves chemical alterations through phase I and phase II reactions. Phase I reactions introduce functional groups like OH or NH2 through oxidation, reduction or hydrolysis. Phase II then involves conjugating these groups to molecules like glucuronic acid or sulfate, making the substances more polar and excretable in urine or bile. This overall process of metabolism and conjugation serves to terminate the pharmacological effects of drugs and remove them from the body.
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Factors affecting excretion of drug from body
The excretion of drugs is affected by various physicochemical and biological factors. Drugs with larger molecular weights and those that are more lipid soluble are excreted less than drugs with smaller molecular weights or lower lipid solubility due to decreased glomerular filtration and increased distribution in tissues. Additionally, drugs that have higher volumes of distribution, are highly protein bound, or have lower renal blood flow are excreted less through the kidneys compared to drugs with opposite properties. Other factors like ionization, urine pH, age, and presence of diseases can also influence a drug's renal clearance and excretion.
Distribution and its factors affecting
In this powerpoint the distribution process of drugs and various factors that alters drug distribution is discussed..
Biomolecules - Nucleic acids
This powerpoint includes the nucleic acid and its types, its biological importance in our human body..
Anti platelet drugs
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Anti ulcer drugs
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Congestive cardiac failure
The document provides an overview of congestive heart failure including its definition, epidemiology, etiology, types, risk factors, pathogenesis, signs and symptoms, diagnosis, management goals, and pharmacological and surgical treatment options. It discusses how heart failure results from the heart's inability to pump sufficient blood and covers compensatory mechanisms and factors that can precipitate or exacerbate the condition. Treatment focuses on improving quality of life, relieving symptoms, and slowing disease progression through lifestyle changes, medications like diuretics, ACE inhibitors, beta-blockers, and surgery in some cases.
Proteins
This document defines different types of proteins and describes their characteristics. It discusses simple proteins like albumin and globulin, conjugated proteins including nucleoproteins and phosphoproteins, and derived proteins such as proteoses and peptides. Simple proteins contain amino acids and differ in solubility, with albumin soluble in water and globulin insoluble. Conjugated proteins combine proteins with other molecules like nucleic acids or phosphate. Derived proteins are denatured or breakdown products of simple proteins.
Lipids
1. Lipids are greasy substances found in both plants and animals that are insoluble in water but soluble in organic solvents. They include fats, oils, waxes, phospholipids, and sterols.
2. Lipids serve as an energy store and structural component of cell membranes. Major sources include nuts, seeds, milk, eggs, liver, and fish oils.
3. Lipids can be categorized as simple lipids like fats and oils, or compound lipids that contain additional components like phospholipids, glycolipids, and lipoproteins.
Absorption of Drugs in human body
This document discusses drug absorption mechanisms. It defines absorption as the entry of drug molecules into systemic circulation from the site of administration. It then describes the main mechanisms of drug absorption as passive diffusion, filtration, and carrier-mediated transport including facilitated diffusion and active transport. Passive diffusion involves diffusion of lipophilic drugs down their concentration gradient without carriers. Filtration and carrier-mediated transport help absorb other types of drugs.
Carbohydrates
Carbohydrates are widely distributed in plants and animals. They function primarily as a fuel in the body by liberating energy through oxidation. Certain carbohydrate products also promote further oxidation of foods and can be used as starting materials for other biological compounds. Chemically, carbohydrates contain carbon, hydrogen, and oxygen in proportions similar to water, with glucose having the formula C6H12O6. Carbohydrates can be classified based on the number of carbon atoms in their molecular structure, ranging from di- to heptoses.
Route of administration of drugs
This document discusses various routes of drug administration. The enteral route, which includes oral and sublingual administration, is the safest, most economical and convenient. Oral administration has advantages like ease of self-administration but disadvantages like variable drug absorption in the GI tract. Sublingual administration allows rapid drug absorption bypassing first-pass metabolism but only small doses can be used. The rectal route uses suppositories inserted into the rectum.
Pharmacology
This document provides definitions and classifications related to the field of pharmacology. It defines pharmacology as the study of drugs and their actions in the body. Key topics covered include the definitions of pharmacokinetics, pharmacodynamics, pharmacoepidemiology, pharmacoeconomics, pharmacogenomics, toxicology, pharmacovigilance, therapeutics, clinical pharmacology, receptors, ligands, potency, and tolerance. It also discusses sources of drug information like pharmacopeias and the expanding scope of pharmacology to incorporate new approaches like computer-assisted drug design and novel drug delivery methods.
Factor effecting drug absorption
The document discusses factors that influence drug absorption in the gastrointestinal tract, noting that the small intestine has the greatest absorption due to presence of enzymes and water absorption, while the stomach and colon have less absorption. It also outlines how pH levels, binding proteins, metabolism, age, sex, body weight, food, medications, and disease states can impact drug absorption in the GI tract. Specifically, it indicates that unionized drugs are absorbed faster than ionized drugs due to greater lipid solubility.
Skeletal system
The skeletal system comprises bones and cartilages that support the body, allow for movement, protect internal organs, and produce blood cells. There are two main types of bones - long bones in the limbs and flat/irregular bones in the skull, vertebrae, and pelvis. Bones form through either intramembranous or endochondral ossification and are constantly remodeled throughout life. The axial skeleton includes the skull, vertebral column, and thoracic cage, providing structure and protection to the head, neck and trunk.
Hypersensitivity reactions
The document discusses hypersensitivity reactions, which occur when the immune system overreacts to substances that are normally harmless. It defines four main types of hypersensitivity reactions:
Type I are immediate reactions mediated by IgE antibodies. Type II involve cytotoxic antibodies against self-cells. Type III occur when antigen-antibody complexes activate the complement system. Type IV are delayed hypersensitivity reactions.
The document provides examples like allergies, transfusion reactions, and serum sickness. It explains the underlying immunology and describes associated symptoms, laboratory tests, and management approaches for different hypersensitivity reactions like rhinitis, asthma, and anaphylaxis.
Epilepsy
Epilepsy is a neurological disorder characterized by recurrent seizures caused by excessive neuronal activity in the brain. A seizure occurs when nerve cell activity in the brain is disturbed, causing changes in movement, behavior, sensation (including "auras"), or consciousness. Epilepsy is defined as having two or more unprovoked seizures. Seizures have many potential causes including genetics, brain injury, and unknown factors. Treatment involves medications called anti-epileptic drugs which help control seizures by various mechanisms such as enhancing GABA inhibition or blocking sodium channels. Diagnosis involves a detailed history and examination, and may include tests like EEG, MRI, and genetic testing.
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3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
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2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
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Matabolism of drugs in Humans
- 1. METABOLISM ASIYABI.M ASSISTANT PROFESSOR DEPARTMENT OF PHARMACOLOGY
- 2. DEFINITION The body metabolises some drugs chemically. Metabolism may either result in the formation of inactive substance or substances that may resemble to orginal drug in term of therapeutic activity or toxicity.
- 3. Liver is the main site of metabolism for most drug and hence almost every drug passes through the liver. For the conversion of prodrug to active metabolites or for the conversion of activite drug to inactive form ,the drugs must enter the liver,. Where many enzymes are acting upon them.
- 4. A specific group of cytochrome p-450 enzyme involve in livers primary mechanism for metabolising drugs. The rate of metabolising of many drugs is controlled by the level of these cytochrome p-450 enzymes. Since the enzymes posses a limited capacity of matabolism, they are burdened , When the levels of drug present in the blood are high.
- 6. ENZYME INVOLVESD DRUG METABOLISM 1) Enzyme involved in phase I metabolism: i) In oxidation: Cytochrome p450 monooxygenase system. Flavin containing monooxygenase system,Alcohol dehydrogenase and aldehyde dehydrogenase. ii) In Reduction: NADPH- cytochrome p450 reductase, and reduced cytochrome p450. It is important to note that a chemical can enter substrate cycle during reduction
- 7. iii) In hydrolysis: Esterase, amidase, and epoxide hydrolase. 2) Enzyme involved in phase II metabolism: i)In methylation: Methyltransferase. ii)In sulphation: Glutathione s- transferases and sulfotransferases. iii) In Acetylation: N-acetyltransferases iv) In Glucuronidation: UDP- glucuronosyltransferases.
- 8. FACTOR EFFECTING DRUG METABOLISM 1) Inhibitors: Certain drugs like cimetidine, omeprazole, ciproflaxin can inhibit enzyme that metabolites a drug . Since the metabolite enzyme are inhibited, the metabolism of the administered drug decreases which in turn leads to an increase in the duration of its action. 2) Stimulators: Certain drug like Phenobarbitone and rifampicin can increase the activity of enzymes that metabolise a drug. Hence it proves advantageous when drug ike phenytoin and warfarin are administered as it increase their metabolism.
- 9. Age: Young children show poor drug metabolism as metabolic enzyme system are not developed completely. For example, grey baby syndrome is seen in infants on administration of chloramphenicol as glucuronyl transferase required for the inactivation of chloramphenicol is lacking in them. Sex: In comparison to males the females possess lesser ability for drug metabolism. Species: Some enzyme may be species – specfic.for example, atropinase: rabbits possess this enzyme and hence they are able to metabolise atropine (therefore atropine is non- toxic for rabbits) however the enzyme atropinase is absent in humans and hence atropine proves toxic for humans.
- 10. Genetics: Drug metabolising enzymes show hereditary patterns deficients of either of the enzyme system can be inherited from one generation to the other. Example an individual in whom the enzyme Glucose -6- phosphate dehydrogenise is genetically deficient show haemolysis when primaquine is administered to them. Body Temperature: Temperature of the body is directly proportional to drug metabolism. Drug metabolism has been found to increase with an increase with body temperature and vice versa.