Drug Therapy and Pharmacotherapy

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Questions and Answers

What is the primary purpose of drug therapy?

To enable patients to avoid surgery

To treat the underlying condition or provide symptomatic relief (correct)

To provide nutritional support to patients

To enhance the effectiveness of physical therapy

Which key property of a drug refers to its ability to specifically target the desired action without affecting non-desired targets?

Selectivity (correct)

Affinity

Efficacy

Concentration

What does the term 'concentration' in relation to drug properties refer to?

The effectiveness of a drug in increasing heart rate

The amount of drug present at the site of action versus the risk of toxicity (correct)

The frequency of drug administration in a treatment regimen

The total amount of drug in the bloodstream

What aspect of a drug relates to how long it maintains its therapeutic effect before being depleted?

Time Signup and view all the answers

Which of the following statements best describes the concept of drug selectivity?

Drugs should target specific receptors while sparing others Signup and view all the answers

What is a common way that antibacterials interfere with bacterial life?

By blocking metabolic pathways Signup and view all the answers

Which structure can antibacterials interfere with to kill or inhibit bacteria?

Cell wall Signup and view all the answers

What is a characteristic of antimicrobial agents?

They can prevent multiplication of pathogens Signup and view all the answers

Which of the following mechanisms is NOT targeted by antibacterials?

Promoting amino acid synthesis Signup and view all the answers

How do antibacterials achieve selectivity towards bacteria without harming the host?

By interacting with bacterial-specific structures Signup and view all the answers

The two common routes of administration are _ and ____

The two common routes of administration are systemic and local. Signup and view all the answers

What are the three common routes of injection?

Intravenous, intramuscular and subcutaneous Signup and view all the answers

Which of the following ADME principles primarily determines the duration of a drug's effect in the body?

Metabolism Signup and view all the answers

Which ADME principle is directly responsible for the concentration of a drug in the blood after administration?

Absorption Signup and view all the answers

Which ADME principle explains why a drug might be more concentrated in certain tissues than others?

Distribution Signup and view all the answers

Which ADME principle is MOST influenced by the drug's chemical structure and properties?

Metabolism Signup and view all the answers

Which ADME principle is primarily responsible for eliminating a drug from the body?

Excretion Signup and view all the answers

What does pharmacodynamics primarily study?

What the drug does to the body and its target Signup and view all the answers

Which of the following best describes potency in pharmacology?

The dose required to produce a given effect Signup and view all the answers

How is the relationship between drug concentration and its effects characterized?

It can be complex and often nonlinear Signup and view all the answers

What aspect of pharmacokinetics involves the elimination of the drug from the body?

Excretion Signup and view all the answers

What relationship do PK and PD together represent?

An exposure/response relationship Signup and view all the answers

What is the primary difference between bacteriostatic and bactericidal agents?

Bacteriostatic agents inhibit bacterial growth, while bactericidal agents kill bacteria. Signup and view all the answers

Which of the following statements is TRUE regarding the spectrum of activity of antimicrobials?

Broad-spectrum antimicrobials are always preferred over narrow-spectrum antimicrobials due to their wider effectiveness. Signup and view all the answers

The minimum inhibitory concentration (MIC) of an antibiotic is defined as:

The lowest concentration of antibiotic that completely inhibits bacterial growth. Signup and view all the answers

Which of the following is NOT a factor that influences the killing of a pathogen within the host?

The route of administration of the antibiotic. Signup and view all the answers

Which of the following describes the killing pattern of an antimicrobial that exhibits a time-dependent effect?

The antimicrobial's effect is dependent on the duration of exposure, regardless of concentration. Signup and view all the answers

What is the purpose of setting breakpoints for antimicrobial agents?

To categorize bacterial strains as susceptible, intermediate, or resistant Signup and view all the answers

What is the maximum concentration of a drug residue in an animal consumable product that is legally tolerated?

Maximum residue limits (MRLs) Signup and view all the answers

What is the time period that must elapse between the last administration of a veterinary medicine and the slaughter or production of food from that animal?

Withdrawal period Signup and view all the answers

What is a factor that influences the choice of an antimicrobial agent?

Antimicrobial action and effect Signup and view all the answers

What is defined as the daily intake of a substance that, over the entire lifetime of a human, appears to be without adverse effects or harm to the health of that human?

Acceptable daily intake (ADI) Signup and view all the answers

What is the primary way in which acquired antibiotic resistance arises?

Transfer of resistance genes between bacteria Signup and view all the answers

How does the use of antibiotics contribute to the spread of antibiotic resistance?

Antibiotics select for resistant bacteria, allowing them to thrive. Signup and view all the answers

Which of the following statements BEST describes the role of innate resistance in bacteria?

Innate resistance is a pre-existing characteristic of a bacterial species. Signup and view all the answers

How do resistant bacteria contribute to the spread of antibiotic resistance?

Resistant bacteria directly transfer resistance genes to susceptible bacteria. Signup and view all the answers

Which of the following is NOT a direct consequence of the increasing prevalence of antibiotic resistance?

Development of new antibiotics that are more effective against resistant strains. Signup and view all the answers

Study Notes

Drug Therapy (Pharmacotherapy)

Definition: A medical treatment that utilizes one or more drugs to provide symptomatic relief, treat the underlying condition, or act as a prevention for other diseases.

Key Properties of a Drug

Selectivity: A drug's ability to target desired targets while avoiding non-desired targets.
Concentrations: A drug's ability to achieve sufficient concentrations at the site of action while avoiding toxicity.
Time: A drug's ability to maintain its effect over time without depleting its potency.

Antimicrobial Agents

An antimicrobial agent is a substance that can kill microbes (bacteria, fungi, virus) or prevent their multiplication, reducing their pathogenic effect.
Antimicrobial agents can be of natural, semisynthetic or synthetic origin.

Mechanism of Action

To interfere with bacterial cell life or growth, antibacterials must interact with a vital structure or block a metabolic pathway.
This interaction should not cause direct toxicity for hosts receiving treatment.

Targets of Antimicrobial Action

Cell wall
Plasma membrane
Ribosomes
Metabolic pathways
DNA synthesis
RNA synthesis

Principles of Drug Therapy

The ADME principle is a crucial concept in drug therapy, consisting of four key stages:

ADME Principle

Absorption: The process by which the concentration of a drug increases in the blood after administration
Distribution: The stage where the drug is dispersed throughout the body and its concentration is determined in various tissues
Metabolism: The process of determining the metabolites of a drug, which affects its efficacy and toxicity
Excretion: The final stage, where the drug is eliminated from the body through feces, urine, or other means, and its concentration is measured in these waste products

Pharmacokinetics (PK)

Study of what the body does to the drug, involving four processes: absorption, distribution, metabolism, and excretion

Pharmacodynamics (PD)

Study of what the drug does to the body and the target, including intensity of therapeutic effect and adverse effects
Involves understanding the drug's effect on the body and the target

PK/PD Relationship

Combination of PK and PD, representing an exposure/response relationship
Exposure refers to the drug's presence in the body, while response refers to its effect on the body and target

Dose-Response Relationships

Drug effect is a function of both dose and time
Response to concentration is often complex and nonlinear
Potency is a measure of the drug's effectiveness, defined as the concentration at which 50% of the maximum effect is achieved

Antibacterial Effects

Bactericidal agents kill bacteria, reducing the total number of viable organisms, and usually require active bacterial growth.
Bacteriostatic agents inhibit bacterial growth and replication, allowing the host immune system to eliminate the pathogen.

Spectrum of Activity

Narrow-spectrum antimicrobials act against a limited group of bacteria.
Broad-spectrum antimicrobials act against several groups of bacteria, including G+ and G- groups.
The spectrum of activity is based on the susceptibility of the wild-type population of bacterial species.

In Vitro Evidence

Minimum Inhibitory Concentration (MIC) is the lowest concentration of antibiotic that completely inhibits growth of a specific organism.
Minimum Bactericidal Concentration (MBC) is the lowest concentration of antibiotic that kills bacteria.
Disk diffusion test measures the diameters of inhibition zones around disks containing the antibiotic tested.

Antibiotic Efficacy in Vivo

Antibiotic effectiveness depends on binding to the target site in the bacterium, sufficient concentration within the bacterium, and sufficient time to cause an effect.
Antimicrobial effect is dependent on both concentration and time.
Antibiotics can be classified according to their pattern of activity:
- Concentration-dependent killing pattern: increased drug concentration leads to increased effect.
- Time-dependent killing pattern: the duration of exposure is more important than the concentration.
- Hybrid pattern: both concentration and time are important.
The area under the serum concentration curve (AUC) measures the concentration and duration of antibiotic levels above the target MIC during a dosing interval.

Categorical Classification of Bacterial Strains

Bacterial strains are categorized as Susceptible (S), Intermediate (I), or Resistant (R)

Criteria for Setting Breakpoints for Pathogen A

Microbiological criteria: in vitro testing
Pharmacological criteria: PK/PD indexes and response to treatment
Clinical criteria: best evidence from literature

Definitions in Pharmacology and Toxicology

ECOFF: epidemiological cut-off
Acceptable Daily Intake (ADI): daily intake of a substance that appears to be without adverse effects or harm to human health over a lifetime
Maximum Residue Limits (MRLs): maximum concentration of a drug residue in animal consumable products that is legally tolerated
Withdrawal Period: time between last administration of a veterinary medicine and slaughter/production of food to ensure food does not contain levels of medicine exceeding MRLs

Factors Affecting Drug Choice

Infection type and severity
Antimicrobial action and effect
Veterinarian's experience
Cost of treatment
Compliance of treatment regimen
Pharmacokinetic drug properties
Host factors
Toxicity of the drug

Antibiotics Resistance Mechanisms

Innate resistance is a natural, preexisting genomic property of bacteria, often due to a mutation or gene.
Acquired resistance is obtained by bacteria through mutation or horizontal gene transfer, which occurs via conjugation, transduction, and transformation.

AMR Generation and Dissemination

Resistant bacteria can pass on their resistance to other bacteria, contributing to the spread of antibiotic resistance.
The use of antimicrobials selectively kills bacteria that are not resistant, increasing the proportion of resistant bacteria in a population.

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Description

This quiz covers the basics of drug therapy, also known as pharmacotherapy, including its application, key properties of a drug, and more. Test your understanding of selectivity, concentrations, and time in drug therapy.