115 Questions
What is pharmacodynamics?
The study of the mechanism of action of drugs and their physiological effects
Which science is a quantitative study?
Pharmacokinetics
What is the study of xenobiotics that have detrimental effects on the body?
Toxicology
What are the agents that depress the parts of the nervous system regulating pain sensation and motor movement called?
Analgesics and general anaesthetics
What does pharmacodynamics refer to?
The mechanisms by which drugs achieve anesthesia
What is the initial drug-receptor interaction considered as?
The action of the drug
What are the most numerous drug receptors in cells?
Proteins
What does an agonist do in relation to a cell?
Stimulates a reaction in the cell
What is the effect of increasing concentrations of ligand in drug-receptor bonding?
Can displace the antagonist
What determines the level of activity of an agonist?
Affinity and potency
What are the mechanisms of drug action apart from cellular mechanisms?
Physical effects, chemical reactions, physicochemical effects, and modification of body fluid composition
What do drug effects on the patient correlate with?
The concentration of the drug in the body
What do antagonist drugs do in relation to a receptor?
Interfere with the receptor without eliciting a reaction
What are the cellular mechanisms of drug action related to?
Physicochemical and biophysical processes, modification of cell membrane structure and function, neurohumoral transmission
What is the main focus of pharmacokinetics?
The study of drug absorption, distribution, metabolism, and excretion
What type of neurons do anaesthetic drugs work by depressing or stimulating?
Excitatory and inhibitory neurons
What determines the clinical effect of a drug?
Dose rate and dosage interval
What describes drug movement in the body?
Pharmacokinetics
What affects the stratum corneum barrier?
Molecular weight and lipophilicity
What is a disadvantage of the enteral route of drug administration?
Drug degradation and food interference
How can drug action be affected?
By food and rapid metabolism by the liver
What affects the effectiveness and potential toxicity of streptomycin?
Administration route
What must happen for drugs and toxins to have a biological effect?
Enter the body
What do pharmacokinetic models describe?
Movement of xenobiotics
What influences drug action and owner compliance?
Route of drug administration
What is a disadvantage of oral drug administration?
Drug degradation in the gastrointestinal tract
What is the aim of drug therapy?
To achieve desired biological response without causing toxicity
What do effective drugs have at high doses?
Potential adverse side effects
What is the main reason for using intravenous administration in veterinary medicine?
Rapid response
Intra-arterial injection is primarily used for achieving high drug concentrations at:
Specific sites
Which type of injection is commonly used in veterinary practice for drug administration?
Intramuscular and subcutaneous injections
Why is inhalation of anaesthetic agents a common practice in veterinary medicine?
Rapid bloodstream access
What is the composition of the blood brain barrier?
Tight junctions between endothelial cells
Under what conditions may the functions of the blood brain barrier be compromised?
In certain pathological conditions
What is the primary purpose of inhalation therapy in veterinary medicine?
Delivering drugs locally without entering the systemic circulation
What physicochemical property is required for a steroid anti-inflammatory drug for inhalation in horses?
Appropriate lipophilicity
What processes are involved in drug absorption?
Getting the drug from the site of administration to the plasma
In the case of phenylbutazone administered in feed for a lame horse, what must the drug pass through to reach the inflamed joint?
Cell membranes
How do organophosphate toxins on the skin of calves reach the brain to cause poisoning?
Pass through cells
Which factors affect the speed and extent of drug penetration across a membrane?
Concentration gradient, surface area, membrane thickness, time in contact, and permeability
What is the first pass effect in drug administration?
Metabolism of drugs by the liver after absorption, affecting drug bioavailability
Why may drugs that do not dissolve in the intestinal contents not be absorbed effectively?
They may not reach the bloodstream
In which animal species may oral drug administration be inconvenient?
Cattle, pigs, and cats
What is a characteristic of rectal administration?
50% bypassing the liver
How can protected oral dosage forms improve drug absorption?
Target drug release in specific parts of the gastrointestinal tract
What challenges do ruminants present for oral drug dosing?
Drug dilution in rumen fluid and inactivation by rumen microflora
What are characteristics of injectable dosage forms?
Rapid and high blood drug concentrations
What is ensured by intravenous administration?
100% bioavailability
What challenges may a farmer face when treating cows with an oral antibiotic for a kidney infection?
Drug absorption, metabolism, and effectiveness
For a dehydrated dog with gastroenteritis, what non-intravenous method of fluid administration may be considered?
Rectal administration of fluids
How can pharmaceutical technologies benefit drug absorption and side effects?
Selective release of drugs to specific parts of the gastrointestinal tract
What is the study of how the body absorbs, distributes, metabolizes, and excretes drugs known as?
Pharmacokinetics
Which science focuses on the mechanism of action of drugs and their effects on cells, tissues, and the body?
Pharmacodynamics
What term is used to describe any foreign chemical substance, including drugs and toxins?
Xenobiotic
What are the agents that depress the parts of the nervous system regulating pain sensation and motor movement called?
Analgesics and general anesthetics
What determines the clinical effect of a drug?
Dose rate and dosage interval
Which route of drug administration is convenient for owners but has disadvantages such as drug degradation and food interference?
Enteral route
What factors affect the stratum corneum barrier?
Molecular weight and lipophilicity
What is a disadvantage of oral drug administration?
Drug degradation in the gastrointestinal tract
What does pharmacokinetics describe?
Drug movement in the body
What influences drug action and owner compliance?
Route of drug administration
What are the disadvantages of the enteral route of drug administration?
Drug degradation and food interference
What is the aim of drug therapy?
To achieve desired biological response without causing toxicity
What is ensured by intravenous administration?
Rapid drug entry into the bloodstream
What is the main focus of pharmacokinetics?
Drug movement in the body
What may affect drug action?
Food and rapid metabolism by the liver
What is the disadvantage of the enteral route of drug administration in terms of convenience for owners?
Drug degradation and food interference
Which route of drug administration allows for erratic drug absorption, with 50% bypassing the liver?
Rectal administration
What is the primary purpose of protected oral dosage forms, such as enteric coatings?
To target drug release in specific parts of the gastrointestinal tract
What is a characteristic of injectable dosage forms?
They protect drugs from intestinal degradation
What is ensured by intravenous administration?
High bioavailability
What challenges do ruminants present for oral drug dosing?
Inactivation by rumen microflora
What type of animal species may find oral drug administration inconvenient?
Cattle, pigs, and cats
What is a disadvantage of rectal administration of drugs?
Erratic drug absorption
What is a potential benefit of pharmaceutical technologies in drug administration?
To selectively release drugs to specific parts of the gastrointestinal tract
What is a disadvantage of oral drug administration for a dehydrated dog with gastroenteritis?
Slow drug action
What is a characteristic of drug absorption in the case of protected oral dosage forms?
Targeted drug release in specific parts of the gastrointestinal tract
What is a primary advantage of injectable dosage forms?
High blood drug concentrations
What is a potential challenge for a farmer treating cows with an oral antibiotic for a kidney infection?
Drug absorption and effectiveness
Which route of drug administration is primarily used for achieving high drug concentrations at specific sites?
Intra-arterial injection
What is the composition of the blood brain barrier?
Tight junctions between endothelial cells
What is the main reason for using inhalation therapy in veterinary medicine?
To deliver drugs locally without entering the systemic circulation
What physicochemical property is required for a steroid anti-inflammatory drug for inhalation in horses?
Appropriate lipophilicity
What processes are involved in drug absorption?
Transport from the site of administration to the plasma
What must phenylbutazone administered in feed for a lame horse pass through to reach the inflamed joint?
Cell membranes
What factors affect the speed and extent of drug penetration across a membrane?
Concentration gradient and surface area
What is the aim of inhalation therapy in veterinary medicine?
To deliver drugs locally without entering the systemic circulation
What is the function of the blood brain barrier?
To protect the brain from potentially harmful substances in the bloodstream
What route of drug administration is commonly used in veterinary practice?
Intramuscular injection
What is the primary purpose of intravenous administration in veterinary medicine?
To achieve rapid response and large volume delivery
What is the primary purpose of intra-arterial injection in veterinary medicine?
To achieve high drug concentrations at specific sites
Which of the following best describes pharmacodynamics?
The study of drug effects on cells and tissues
What is the primary function of an antagonist in relation to a receptor?
Interferes with the receptor without eliciting a reaction
What determines the level of activity of an agonist?
Its affinity and potency
What is the most numerous type of drug receptors in cells?
Proteins
What is the primary factor determining the clinical effect of a drug?
The concentration of the drug in the body
What is the reversible nature of drug-receptor bonding known as?
Dynamic equilibrium
What are the non-cellular mechanisms of drug action?
Physical effects and chemical reactions
What do anaesthetic drugs primarily work by?
Depressing all neurons
What is the term for a drug that interferes with a receptor without eliciting a reaction?
Antagonist
What is the term for the induction of synthesis of specific proteins as a result of receptor activation?
Gene regulation
What do drug effects on the patient correlate with?
The concentration of the drug in the body
What is the primary focus of pharmacodynamics?
Drug effects on cells and tissues
What is the primary focus of pharmacodynamics?
The quantitative effects of drugs on pre-existing cell function
What does an antagonist do in relation to a receptor?
Interferes with a receptor without eliciting a reaction
What determines the level of activity of an agonist?
Its affinity and potency
What are the most numerous drug receptors in cells?
Proteins
What is the effect of increasing concentrations of ligand in drug-receptor bonding?
Increases the level of drug activity
What is the initial drug-receptor interaction considered as?
The action of the drug
What do drug effects on the patient correlate with?
The concentration of the drug in the body
What is the aim of drug therapy?
To achieve a specific and beneficial physiological effect
What must happen for drugs and toxins to have a biological effect?
They must reach their target sites in the body
What is ensured by intravenous administration?
Rapid and complete absorption of the drug
What does pharmacodynamics refer to?
The quantitative study of drug effects on pre-existing cell function
What are the mechanisms of drug action apart from cellular mechanisms?
Physiological effects and chemical reactions
Study Notes
Routes of Drug Administration and Pharmacokinetics
- The first pass effect refers to the metabolism of drugs by the liver after absorption, which can affect drug bioavailability.
- Drugs that do not dissolve in the intestinal contents may not be absorbed effectively.
- Oral drug administration can result in slower drug action compared to injectable routes and may be inconvenient for certain animal species like cattle, pigs, and cats.
- Rectal administration allows for erratic drug absorption, with 50% bypassing the liver, making it useful for certain drug types and conditions.
- Protected oral dosage forms, such as enteric coatings, can target drug release in specific parts of the gastrointestinal tract to improve absorption and reduce side effects.
- Ruminants present unique challenges for oral drug dosing, including drug dilution in rumen fluid and inactivation by rumen microflora.
- Parenteral routes of drug administration include intravenous, intramuscular, subcutaneous, and other methods, each with specific advantages and disadvantages.
- Injectable dosage forms can provide rapid and high blood drug concentrations, protect drugs from intestinal degradation, and avoid first pass metabolism.
- Intravenous administration ensures 100% bioavailability, as all the drug enters the circulation unchanged.
- A farmer treating cows with an oral antibiotic for a kidney infection may face challenges related to drug absorption, metabolism, and effectiveness.
- For a dehydrated dog with gastroenteritis, rectal administration of fluids may be considered, in addition to other non-intravenous methods, depending on the dog's ability to retain the fluid.
- Pharmaceutical technologies can selectively release drugs to specific parts of the gastrointestinal tract, offering potential benefits for drug absorption and side effects.
Pharmacodynamics and Pharmacokinetics: Mechanisms of Drug Action
- Pharmacodynamics refers to the mechanisms by which drugs achieve anesthesia.
- The initial drug-receptor interaction is the action of the drug.
- Drug effects are quantitative and alter pre-existing cell function.
- Anaesthetic drugs work by depressing excitatory neurons, stimulating inhibitory neurons, or depressing all neurons.
- Non-cellular mechanisms of drug action include physical effects, chemical reactions, physicochemical effects, and modification of body fluid composition.
- Cellular mechanisms of drug action involve physicochemical and biophysical processes, modification of cell membrane structure and function, neurohumoral transmission, enzyme inhibitors, and regulatory molecule activation or inhibition through receptor-mediated effects.
- The most numerous drug receptors are the cells' proteins, with properties such as specificity, saturable kinetics, and action vs. effect.
- Results of receptor activation include the induction of synthesis of specific protein, regulation of gated ion channels in the plasma membrane, and regulation of plasma membrane enzymes.
- An agonist stimulates a reaction in the cell, with affinity and potency determining its level of activity.
- An antagonist interferes with a receptor or part of the effector mechanism without eliciting a reaction.
- Drug-receptor bonding is reversible, and increasing concentrations of ligand can displace the antagonist.
- Drug effects on the patient are proportional to the concentration of the drug in the body, correlating with the concentration of the agent in the plasma.
Test your knowledge of routes of drug administration and pharmacokinetics with this quiz. Explore topics such as first pass effect, oral and rectal drug administration, parenteral routes, and the impact of pharmaceutical technologies on drug release and absorption. Ideal for students and professionals in veterinary medicine, pharmacology, and pharmaceutical sciences.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
