Neuropharmacology II Quiz

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Questions and Answers

What primarily determines the bioavailability of a drug post-administration?

The drug's molecular weight

The rate of renal clearance

The drug's formulation type

The drug's absorption and metabolism (correct)

Which statement about protein binding of drugs is correct?

The binding percentage of a drug does not affect its bioavailability.

Only highly protein-bound drugs are effective at receptor sites.

All drugs are equally bound to plasma proteins.

Drugs must be free from protein binding to act at their receptor sites. (correct)

What is the impact of the blood-brain barrier on drug bioavailability?

It facilitates the excretion of protein-bound drugs.

It restricts the passage of certain drugs into the brain. (correct)

It has no effect on drug transport into the brain.

It enhances the absorption of lipophilic drugs.

Which of the following drugs is considered highly protein-bound?

Warfarin Signup and view all the answers

Which factor does NOT influence a drug's bioavailability?

Patient's age Signup and view all the answers

What role does an antagonist play in drug-receptor interaction?

It prevents the binding of the agonist to the receptor. Signup and view all the answers

Which term describes the strength of the binding between a ligand and its target substrate?

Affinity Signup and view all the answers

If a drug acts as a competitive antagonist, which of the following is true?

It decreases the potency of the agonist. Signup and view all the answers

What effect do allosteric modulators have on receptor activity?

They can increase or decrease the response to the agonist. Signup and view all the answers

Which concept best differentiates the relative effectiveness of two ligands at a receptor?

Potency Signup and view all the answers

How does the initial binding of a drug to its target affect the organism?

It initiates a complex signaling cascade that influences cellular behavior. Signup and view all the answers

What is the effect of an allosteric inhibitor on agonist activity?

It decreases the binding affinity of the agonist. Signup and view all the answers

What does pharmacokinetics primarily refer to?

The time course of a drug in the body Signup and view all the answers

Which of the following best defines bioavailability?

The ability of a drug to produce an effect on an organism Signup and view all the answers

What role do the liver and kidneys play in pharmacokinetics?

They are involved in the clearance and elimination of drugs Signup and view all the answers

Which statement best describes the administration of drugs in pharmacokinetics?

It determines the bioavailability and pharmacodynamics of the drug Signup and view all the answers

Which of the following factors influence the pharmacokinetics of a drug?

Its absorption, stability, and elimination Signup and view all the answers

Which stage of pharmacokinetics involves the movement of the drug to its target after administration?

Distribution Signup and view all the answers

What does 'clearance' refer to in pharmacokinetics?

The volume of plasma cleared of the drug per unit time Signup and view all the answers

Which route of administration is most likely to result in a rapid onset of action?

Sublingual Signup and view all the answers

Which is NOT a component of pharmacokinetics?

Histology Signup and view all the answers

What does clearance in pharmacokinetics primarily refer to?

The elimination of the drug from the body Signup and view all the answers

Which organ is primarily involved in drug metabolism in the body?

Liver Signup and view all the answers

Which biological process can affect the stability of a drug in the body?

Metabolic pathways and liver function Signup and view all the answers

How is the pharmacokinetics of a drug assessed?

By examining absorption, distribution, metabolism, and elimination Signup and view all the answers

Which of the following statements about bioavailability is true?

It is affected by the route of administration. Signup and view all the answers

What is the primary focus of pharmacokinetics?

What the body does to drugs Signup and view all the answers

Which stage does NOT involve the physical and chemical interaction of the drug with body tissues?

Administration Signup and view all the answers

Which process describes the bodily removal of the drug after it has exerted its effect?

Excretion Signup and view all the answers

Which of the following best describes the concept of absorption in pharmacokinetics?

The passage of the drug from the site of administration into the bloodstream Signup and view all the answers

Which is NOT a compartment through which drugs may be distributed within the body?

Mucosa Signup and view all the answers

Which administration route is characterized by delivering medication directly into the muscle tissue?

Intramuscular Signup and view all the answers

What effect does a pH as low as 1-2 have on oral bioavailability?

Enhances dissolution via acid and pepsin activity Signup and view all the answers

Which route of administration involves delivering medication into the cerebral ventricular system?

Intracerebroventricular Signup and view all the answers

What is a significant disadvantage of the subcutaneous route of drug administration?

Limited to small volume doses Signup and view all the answers

Which factor does NOT affect oral bioavailability during tablet dissolution?

Temperature of the medication Signup and view all the answers

Which parenteral route involves injecting medication directly into the peritoneal cavity?

Intraperitoneal Signup and view all the answers

What is the primary purpose of using intravenous drug administration?

Immediate systemic effect Signup and view all the answers

Which of the following routes is NOT typically classified as parenteral?

Sublingual Signup and view all the answers

What occurs during the fragment formation of a tablet during dissolution?

Increased surface area available for dissolution Signup and view all the answers

Which of the following best describes buccal administration?

Sublingual absorption facilitated between the gums and cheek Signup and view all the answers

Study Notes

Basic Principles of Neuropharmacology II

The image depicts a person pouring water from a bottle into a brain.
Igor Morski's quote: "Someone is making water out of your brain."
Learning outcomes include defining drugs and medicines, reviewing drug actions in biological systems, defining pharmacodynamics and pharmacokinetics, discussing bioavailability (admin., release, absorption, distribution, metabolism, and excretion), and discussing volume of distribution and clearance.

Basic Terms: Ligands, Drugs, and Medicines

A ligand is any chemical that binds to a receptor (can be agonist or antagonist).
A drug is a substance (other than food) used for prevention, diagnosis, treatment, or symptom relief of diseases or abnormal conditions. Drugs can alter brain and body function, potentially causing changes in mood, awareness, thoughts, feelings, or behavior, with opioids being a potential example of drugs that can cause addiction.
A medicine refers to practices and procedures for preventing, treating, or relieving diseases or symptoms; it may also refer to a legal drug for the same purpose.
Drugs affecting behavior are known as psychotropic agents, but other terms such as chemical or compound are also used.

Drugs are All Around Us

Antidepressants, anti-anxiety, anticonvulsants, and antipsychotics are common medications.
Some drugs can affect other organ systems and can cause unpleasant side effects.
Common substances such as caffeine, alcohol, and nicotine also affect the central nervous system.
In some individuals, drugs can be used compulsively, resulting in addiction.

The Action of Drugs on Neural Targets

The initial drug target determines the cells and circuits affected, and the potential for both efficacy and side effects.
Initial drug binding is just the beginning of a signaling cascade influencing cell behavior, neural circuits, and animal behavior.

Agonists, Antagonists, and Modulators

Ligands can alter agonist responses.
Competitive antagonists compete with agonists for the binding site.
Allosteric modulators can either enhance or reduce agonist responses at separate sites.

Affinity, Potency, and Efficacy

Affinity (Ka) is the strength of ligand binding to its target.
Efficacy is the ability of a drug to produce a maximal biological effect at a receptor.
Potency is the amount of ligand (agonist or antagonist) needed to elicit a specific biological effect.

Pharmacodynamics

Pharmacodynamics describes the time course and intensity of drug effects on the body.
Drug action is determined by affinity, efficacy, potency, and concentration-response relationships, spare receptors, and amplification.
The ability of a drug to produce an effect depends on these underlying mechanisms.

Pharmacodynamics vs. Pharmacokinetics

Pharmacodynamics focuses on the effects of a drug "what the drug does to the body".
Pharmacokinetics describes the journey of a drug in the body "what the body does to the drug".
Pharmacodynamics considers drug action at the site of action, whereas pharmacokinetics considers absorption, circulation, metabolism, excretion, etc.

Pharmacokinetics and Bioavailability

Pharmacokinetics describes the movement/time course of a drug in the body.
Bioavailability measures the ability of a drug to reach the target, from absorption to elimination.

Pharmacokinetics Stages

Route of administration
Release/liberation
Absorption
Distribution
Metabolism
Excretion

Getting Drugs into the Brain - Administration

Enteral routes (through the intestine) include oral (slow onset), sublingual, buccal, and rectal administrations.
Parenteral routes include intravenous, intramuscular, subcutaneous, inhalation, and intracerebroventricular or intracerebral routes.

Pros and Cons of Drug Administration Routes

Enteral routes are convenient and non-sterile, but oral administration can have significant first-pass metabolism effects and erratic absorption.
Parenteral routes offer faster action, complete absorption, and potentially less degradation, but some may have greater pain or risks of complications.

Oral Bioavailability - Tablet Dissolution (Release/Liberation)

Tablet dissolution in the acidic environment of the stomach (pH 1–2) into solution (fragmentation and smaller particles) is essential for absorption.
Several factors like pH, pepsin, food, drug formulation, and surface area affect absorption.

Oral Bioavailability - Absorption

Most drugs are absorbed in the duodenum and jejunum of the small intestine.
Villi increase surface area for absorption.
Epithelial cells, capillary networks, and the portal vein system enhance absorption.
Numerous processes like passive diffusion, convective absorption, active transport, facilitated transport, ion pair formation, and pinocytosis enable absorption.
Drug absorption also depends on intestinal motility (influenced by time of day, exercise, disease, or food consumption).

Oral Bioavailability - First Pass Metabolism

Most venous outflow from the stomach and intestines goes to the liver via the portal vein.
Cytochrome P450 enzymes in the liver play a role in metabolizing endogenous substances and drugs.
Bioavailability is reduced because of the liver, which inactivates many drugs before they reach systemic circulation.

Bioavailability Affected by Plasma Proteins

Many drugs bind to plasma proteins, primarily albumin, which reduces their bioavailability because only free drug can act at the receptor.

Bioavailability Affected by Barriers

Various factors, including paracellular, transcellular, transport proteins, receptor-mediated transcytosis, and adsorptive transcytosis, can potentially affect drug bioavailability, especially when crossing barriers like the blood-brain barrier.

Drugs into the Brain - Bioavailability

Bioavailability is affected by absorption, metabolism, excretion, binding to plasma proteins, and blood-brain barrier penetration.

Drug Pharmacokinetics Decides Dosing Regimen

Pharmacokinetic parameters such as concentration-time profiles (Cmax), time to reach Cmax (tmax), and area under the curve (AUC) help define dosing regimens.
Unbound drug can access the receptor to exert activity.

Pharmacokinetics & Dosing Terms Used

Describes various pharmacokinetic terms used in calculating and defining drug dosages.

Fundamentals of Pharmacokinetics

Key concepts in pharmacokinetics, such as volume of distribution, clearance, and elimination half-life.

Pharmacokinetics - Volume of Distribution

Volume of distribution (Vd) is a hypothetical volume that a drug would occupy if it were distributed at the same concentration as in the plasma.

Pharmacokinetics - Clearance

Clearance (CL) describes the rate at which a drug is removed from the body.

Case Study - Fate of Ethanol in Body

Describes the pharmacokinetic and pharmacodynamic processes of ethanol in the body, starting from administration to effects, factors influencing blood alcohol levels (BAC), and influencing factors including the administration route, absorption, distribution, metabolism, and excretion.

Case Study - Ethanol Distribution Volume

Describes the factors of age, weight, height, and sex differences in the body composition of patients and their correlation to ethanol (alcohol) distribution volume.

Variability in Drug Response

Drug response can vary due to aspects including appearance, philosophy, physiology/biochemistry, occupation, and genetics (genotype vs. phenotype).

Summary: Pharmacodynamics & Pharmacokinetics

Pharmacodynamics (PD) is the study of drug effects on the body.
The ability of a drug to produce effects depends on characteristics such as affinity, efficacy, potency, concentration-response relationships, spare receptors, and amplification.
Pharmacokinetics (PK) is the study of a drug's movement through the body.
Factors include absorption, distribution, metabolism, and excretion of a medicine.
Bioavailability and the rate of clearance determine the drug effect time course.

Study Materials

Lists books related to the subject: Psychopharmacology, Molecular Neuropharmacology, and Rang & Dale's Pharmacology.

Example Question L3

Pharmacokinetics is the time course of a drug in the body.

Weekly Schedule

A detailed schedule of topics related to neuropharmacology in a course.

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Description

Test your knowledge on the basic principles of neuropharmacology. This quiz covers topics like pharmacodynamics, pharmacokinetics, and the definitions of drugs and medicines. Enhance your understanding of how drugs interact within biological systems.