What is absorption of drugs?
Absorption is the process of a drug moving from its site of delivery into the bloodstream. The chemical composition of a drug, as well as the environment into which a drug is placed, work together to determine the rate and extent of drug absorption. Absorption is the process of delivering a drug into the blood stream.
What is excretion of drugs from the body?
Drug excretion is the removal of drugs from the body, either as a metabolite or unchanged drug. There are many different routes of excretion, including urine, bile, sweat, saliva, tears, milk, and stool.
How does a drug enter the body?
Once the drug is absorbed through the skin, it enters the bloodstream to be carried throughout the body and possibly to the brain. Some drugs can be inhaled as gases. Gases penetrate the lining of the lungs very quickly, which allows the drug to enter the bloodstream.
How are drugs absorbed through the nasal mucosa?
Highly fat-soluble drugs are easily absorbed through the skin. The nasal mucosa has a large number of fine villi, which can significantly increase the effective surface area for drug absorption.
How a drug is absorbed and excreted is called?
Pharmacokinetics: The Absorption, Distribution, and Excretion of Drugs.
How a drug is absorbed or excreted is called quizlet?
Terms in this set (84) Pharmacokinetics. is the process of drug movement throughout the body that is necessary to achieve drug action. The four processes are absorption, distribution, metabolism (or biotransformation), and excretion (or elimination) Absorption.
What is absorption and excretion?
Absorption is the transfer of a chemical from the site of exposure, usually an external or internal body surface, into the systemic circulation. Toxicants are removed from the systemic circulation by biotransformation, excretion, and storage at various sites in the body.
How is drug excreted in the body?
Most drugs, particularly water-soluble drugs and their metabolites, are eliminated largely by the kidneys in urine. Therefore, drug dosing depends largely on kidney function. Some drugs are eliminated by excretion in the bile (a greenish yellow fluid secreted by the liver and stored in the gallbladder).
When a drug is eliminated from the body it is known as metabolism quizlet?
What is excretion? The process of removing a drug of its metabolites from the body occurs primarily in the urine.
How are drugs absorbed distributed metabolized and eliminated in the body?
Following administration, the drug must be absorbed and then distributed, usually via vessels of the circulatory and lymphatic systems; in addition to crossing membrane barriers, the drug must survive metabolism (primarily hepatic) and elimination (by the kidney and liver and in the feces).
What is meant by drug metabolism and excretion?
Metabolism is the conversion of generally more lipophilic xenobiotic compounds to hydrophilic metabolites that can be eliminated from the body via excretion2. Metabolism of a drug involves enzymes and several investigative studies may be needed to identify major metabolites and relevant metabolic pathways.
What is pharmacokinetics of a drug?
Pharmacokinetics is currently defined as the study of the time course of drug absorption, distribution, metabo- lism, and excretion. Clinical pharmacokinetics is the application of pharmacokinetic principles to the safe and effective therapeutic management of drugs in an individual patient.
What is the process of pharmacokinetics?
Pharmacokinetics is the movement of a drug through the body's biological systems, these processes include absorption, distribution, bioavailability, metabolism, and elimination. It can be used to study the onset, duration, and intensity of the effect of a drug.
What organ excretes drugs?
The main organs responsible for drug excretion are the kidneys (renal excretion) and the liver (biliary excretion). Other organs can be involved in excretion, such as the lungs for volatile or gaseous agents. Drugs can also partially be excreted into sweat, saliva and tears.
What action occurs when the drug is absorbed into the bloodstream?
The most common mechanism of absorption for drugs is passive diffusion. This process can be explained through the Fick law of diffusion, in which the drug molecule moves according to the concentration gradient from a higher drug concentration to a lower concentration until equilibrium is reached.
Which of the following organs excretes drugs quizlet?
Rationale: The kidney is the main organ responsible for the excretion of medication metabolites.
What is drug tolerance and why does it occur?
Tolerance is a person's diminished response to a drug, which occurs when the drug is used repeatedly and the body adapts to the continued presence of the drug.
How does Half Life apply to steady state?
The time taken to reach the steady state is about five times the half life of a drug. Drugs like digoxin and warfarin with a long half life will take longer to reach a steady state than drugs with a shorter half life.
Why is bioavailability important?
It is the most common route of administration used for most drugs.[9] Bioavailability and pharmacokinetic studies are aimed to identify a suitable dosage regimen for a new drug candidate to ensure its therapeutic effectiveness and safety, to identify new formulations of the existing drugs, compare the bioavailability for a drug with different dosage forms or the same dosage form of a different manufacturer, and to control the quality of a drug product during the early stages of marketing by the determination of the effect of different physicochemical and physiological factors on absorption.
What is the bioavailability of a drug?
The bioavailability of a drug product is known as the rate and extent of its absorption. A better understanding of the drug absorption process and affecting factors play an important role in achieving better bioavailability and thus better therapeutic effect.[3] .
What is the most important principle in pharmacokinetics?
The most important principle in pharmacokinetics theory is drug absorption which is defined as the transportation of the unmetabolized drug from the site of administration to the body circulation system.[2] .
How is the benefit of a drug determined?
The benefit and toxicity of a drug are determined by its concentration in the plasma. Bioavailability plays an essential role in maintaining drug plasma concentration within the therapeutic range. Since the bioavailability of a drug is directly dependent on the rate and extent of drug absorption at the site of administration, factors affecting drug absorption, including the route of administration directly affect the bioavailability of that drug. For a drug with optimal physicochemical absorption properties under normal physiological conditions, the rate and extent of drug absorption are directly affected by the route by which the drug is administered.
What is clinical pharmacokinetics?
The application of pharmacokinetic methods to ensure patients are treated safely and effectively is known as clinical pharmacokinetics. The introduction of pharmacokinetics as a discipline has facilitated the development of rational drug therapy, the understanding of drug action and metabolism, understand of concentration-effect relationship, ...
What is the study of drug absorption, distribution, metabolism, excretion, and how the body affects the?
The study of drug absorption, distribution, metabolism, excretion, and how the body affects the drug is known as pharmacokinetics. The application of pharmacokinetic methods to ensure patients are treated safely and effectively is known as clinical pharmacokinetics. The introduction of pharmacokinetics as a discipline has facilitated ...
How do drugs absorb?
The most common mechanism of absorption for drugs is passive diffusion. This process can be explained through the Fick law of diffusion, in which the drug molecule moves according to the concentration gradient from a higher drug concentration to a lower concentration until equilibrium is reached. Passive diffusion can occur in an aqueous or lipid environment. Aqueous diffusion occurs in the aqueous compartment of the body, such as interstitial space or through aqueous pores in the endothelium of blood vessels. Drugs that are bound to albumin or other large plasma proteins cannot permeate most aqueous pores. On the other hand, lipid diffusion occurs through the lipid compartment of the body. Therefore it is considered the most important factor for drug permeability due to the greater number of lipid barriers that separate the compartments of the body. The lipid-aqueous partition coefficient of the drug can be used to determine how rapidly the drug moves between lipid and aqueous mediums.
What happens when a drug is administered intravenously?
Note, that if a drug is administered intravenously (placed directly into the blood stream), the need for absorption is bypassed entirely. For drug absorption to occur, a drug must cross biologic barriers (e.g. epithelial/endothelial cells, etc.).
What is the most efficient way to absorb drugs?
For drug absorption to be most efficient, the properties of the drug itself and the pH of the environment where the drug is located must be considered . Most drugs are either weak acids or weak bases. Drugs that are weak acids will pick up a proton when placed in an acidic environment and will, thus, be un-ionized.
Where are acidic drugs most likely to be absorbed?
As a result, acidic drugs are most likely to be absorbed in the acidic areas of the proximal duodenum; whereas, basic drugs will be best absorbed in more alkaline areas of the distal ileum.
How do drugs move across cellular barriers?
Only a few drugs move across cellular barriers in an “active” way; that is, a way that requires energy (ATP) and moves the drug from an area of low concentration to an area of higher concentration. On the other hand, most drugs cross cellular barriers via passive diffusion; that is, drugs simply move from an area of higher concentration to an area of lower concentration by diffusing through cell membranes. This type of drug movement does not require any energy expenditure, but will be influenced by the size of the drug and the solubility of the drug.
What are the factors that affect drug absorption?
Other factors that also impact drug absorption include the following: Physiologically, a drug’s absorption is enhanced if there is a large surface area available for absorption (e.g. villi/microvilli of intestinal tract) and if there is a large blood supply for the drug to move down its concentration gradient.
What is the purpose of the three page article on absorption?
The article summarizes the different processes of absorption including passive diffusion , facilitated passive diffusion, active transport and pinocytosis. Summaries of oral and parenteral administration, and controlled-release forms are mentioned as well.
How is absorption accomplished?
Absorption can be accomplished by administering the drug in a variety of different ways (e.g. orally, rectally, intra-muscularly, subcutaneously, inhalation, topically, etc.). Note, that if a drug is administered intravenously (placed directly into the blood stream), the need for absorption is bypassed entirely.
What is transdermal administration?
Transdermal administration —The misuse of drugs via this route is not as common as oral administration or injection. Substances that are administered this way may be done so through a patch applied to the skin, which allows the drug to be absorbed into the bloodstream and circulate throughout the body. 11 An example of a drug administered this way is the fentanyl patch. 12
How does the circulatory system work after a drug is administered?
After a drug is administered, it is absorbed into the bloodstream. The circulatory system then distributes the drug throughout the body. Then it is metabolized by the body. The drug and its metabolites are then excreted. 5,6.
What is IV injection?
IV Injection —Injection into a vein – or intravenous (IV) injection – delivers the substance directly into the bloodstream. 7 Drugs administered this way will be 100% absorbed by definition of absorption. 6 While the effects of a drug delivered in this manner come on quickly, they also tend to dissipate quickly. 7
What happens when you cross the blood brain barrier?
Repeated use of drugs that are able to cross the BBB can also impact the brain in numerous other ways, such as making it hard to feel pleasure from natural rewards (leading to continued, compulsive drug use) and causing problems with executive functioning (planning, making decisions, and solving problems ). 14
What is subcutaneous injection?
Subcutaneous Injection —A subcutaneous injection is an injection into the fatty tissue underneath the skin, which enables the substance to move to the capillaries or lymphatic vessels and into the bloodstream. 7
What determines the speed of onset of effects?
The method by which a drug is administered, along with other factors , determines the speed of onset of effects. 4. Drugs undergo four stages within the body: absorption, distribution, metabolism, and excretion. After a drug is administered, it is absorbed into the bloodstream. The circulatory system then distributes the drug throughout the body.
How long does it take for a high to go away from smoking?
An example of a rapid and short-lived high from smoking is crack cocaine. The effects are quick but go away within 5 to 10 minutes. 9
What is enteral medicine?
enteral; drugs that are given by mouth (PO), orally, sublingually and rectally.
Which is faster, surface area or rate of absorption?
The larger the surface area of the membrane the faster the rate of absorption.
Do drugs go into fat?
Dose of drugs will go into fat slowly, but will only increase.
What is an agonist?
An agonist is a drug that binds to a receptor:
Is heroin a Schedule 1 drug?
According to the Controlled Substances Act of 1970, heroin is a Schedule 1 drug, meaning it:
How do enteric coatings work?
If an orally administered drug harms the stomach lining or decomposes in the acidic environment of the stomach, a tablet or capsule of the drug can be coated with a substance intended to prevent it from dissolving until it reaches the small intestine . These protective coatings are described as enteric coatings. For these coatings to dissolve, they must come in contact with the less acidic environment of the small intestine or with the digestive enzymes there. However, the coatings do not always dissolve as intended. The tablet or capsule may be passed intact in the feces, especially in older people.
How does a surgical removal of a part of the digestive tract affect drug absorption?
Surgical removal of parts of the digestive tract (such as the stomach or colon) may also affect drug absorption. Where and how long a drug product is stored can affect drug bioavailability. The drug in some products deteriorates and becomes ineffective or harmful if stored improperly or kept too long.
What are the factors that affect drug absorption?
Other factors include a person's age, sex, level of physical activity, and level of stress. Food, other drugs, and digestive disorders can affect drug absorption and bioavailability. For example, high-fiber foods and calcium supplements may bind with a drug and prevent it from being absorbed.
Why do drug manufacturers adjust their variables?
Drug manufacturers adjust these variables to optimize absorption. Because drug products that contain the same drug (active ingredient) may have different inactive ingredients, absorption of the drug from different products may vary. Thus, a drug’s effects, even at the same dose, may vary from one drug product to another.
What is the meaning of "absorption" in medicine?
Drug absorption is the movement of a drug into the bloodstream after administration. (See also Introduction to Administration and Kinetics of Drugs .) Absorption affects bioavailability—how quickly and how much of a drug reaches its intended target (site) of action. Factors that affect absorption (and therefore bioavailability) include.
What is a drug product?
A drug product is the actual dosage form of a drug—a tablet, capsule, suppository, transdermal patch, or solution. It consists of the drug (active ingredient) and additives (inactive ingredients). The active ingredient is the chemical substance (the drug) that is taken to produce the desired effect (such as lowering blood pressure).
What happens if a drug is released too quickly?
If a tablet releases the drug too quickly, the blood level of the drug may become too high, causing an excessive response. If the tablet does not release the drug quickly enough, much of the drug may be eliminated in the feces without being absorbed, and blood levels may be too low.
