Podcast
Questions and Answers
What does pharmacokinetics primarily focus on?
What does pharmacokinetics primarily focus on?
Which of the following is NOT a source of drugs?
Which of the following is NOT a source of drugs?
What is the primary characteristic of passive transfer for drug transport?
What is the primary characteristic of passive transfer for drug transport?
Which drug is an example of a synthetic drug?
Which drug is an example of a synthetic drug?
Signup and view all the answers
What is the effect of metabolic inhibitors on drug transport through simple diffusion?
What is the effect of metabolic inhibitors on drug transport through simple diffusion?
Signup and view all the answers
What is meant by the term 'bioavailability' in pharmacokinetics?
What is meant by the term 'bioavailability' in pharmacokinetics?
Signup and view all the answers
What type of drug administration might involve a needle being injected into a muscle?
What type of drug administration might involve a needle being injected into a muscle?
Signup and view all the answers
Which component is NOT included in the pharmacokinetic principle?
Which component is NOT included in the pharmacokinetic principle?
Signup and view all the answers
What role does the concentration gradient play in drug absorption?
What role does the concentration gradient play in drug absorption?
Signup and view all the answers
Which factor primarily affects the degree of ionization of a weak acid?
Which factor primarily affects the degree of ionization of a weak acid?
Signup and view all the answers
What is the consequence of alkalinizing urine in drug poisoning?
What is the consequence of alkalinizing urine in drug poisoning?
Signup and view all the answers
What is the primary mechanism by which amino acids and glucose are absorbed in the body?
What is the primary mechanism by which amino acids and glucose are absorbed in the body?
Signup and view all the answers
What type of transport allows drugs to pass against a concentration gradient?
What type of transport allows drugs to pass against a concentration gradient?
Signup and view all the answers
In a drug with a pKa of 3.5, which environment will favor its absorption?
In a drug with a pKa of 3.5, which environment will favor its absorption?
Signup and view all the answers
Which factor does not affect the filtration of drugs in capillaries?
Which factor does not affect the filtration of drugs in capillaries?
Signup and view all the answers
What does the term 'pKa' represent in pharmacology?
What does the term 'pKa' represent in pharmacology?
Signup and view all the answers
Study Notes
Drugs
- Chemical substances that stimulate or inhibit existing cell functions.
- Used for treatment, prevention, or diagnosis.
Pharmacokinetics
- The effects of the body on the drug.
- Involves the absorption, distribution, metabolism, and excretion of drugs.
Pharmacodynamics
- The study of the effects of the drug on the body and their mechanisms of action.
Sources of drugs
- Animals: heparin
- Plants: atropine, caffeine, digoxin
- Microorganisms: penicillin
- Synthetic: paracetamol
- Minerals: ferrous sulfate
- Biotechnology: human insulin, tPA
Drug Nomenclature
- Chemical name
- Generic or official name
- Trade or proprietary name
Drug Sales
- Most drugs are restricted by prescription.
- Some drugs are available over-the-counter (OTC).
Components of Pharmacokinetics
- Drug administration: oral, intravenous, intramuscular, subcutaneous
- Absorption
- Distribution
- Metabolism
- Excretion
Transmembrane Movement of Drugs
- Cell Membranes: consist of hydrophobic lipid bilayers interspersed with hydrophilic protein molecules and minute water-filled pores.
- Capillaries and glomeruli have large pores.
- Brain capillaries (except in specific areas), testes, and some other tissues have tight junctions with no intercellular pores.
Processes of Drug Passage
- Passive transfer
- Simple diffusion: most common method
- Drugs move from high to low concentration.
- Requires no energy or carrier.
- Not inhibited by metabolic inhibitors.
- Not saturable.
- Depends on:
- Concentration gradient
- Lipid solubility
- Degree of ionization
- Membrane thickness
- Molecular size
- Lipid solubility: measured by the lipid/water partition coefficient.
- Ionization:
- Most drugs are weak acids or weak bases with a dissociation constant (pKa).
- The degree of ionization is determined by the pKa and pH of the environment.
- Clinical Significance of pKa:
- Aspirin (weak acid) is absorbed from the stomach.
- Amphetamine (weak base) is absorbed from the intestine.
- Renal elimination of drugs can be enhanced by changing urinary pH to increase drug ionization and inhibit tubular reabsorption.
- Filtration: occurs in capillaries with large pores.
- Depends on hydrostatic and osmotic pressures.
- Limited by blood flow, but not by lipid solubility.
- Not saturable.
- Simple diffusion: most common method
- Specialized transport
- Facilitated diffusion: requires a carrier and is saturable.
- Active transport: moves drugs against the concentration gradient (requires energy, carrier, and is saturable).
- Pinocytosis: engulfs large molecules.
Absorption
- Process of entry of a drug from the site of administration to the systemic circulation.
- Factors influencing absorption:
- Factors related to the drug:
- Physicochemical properties
- Formulation
- Dosage form
- Factors related to the site of administration:
- Blood flow
- Surface area
- Presence of food
- pH
- Factors related to the patient:
- Age
- Sex
- Disease state
- Genetic factors
- Factors related to the drug:
Distribution
- Process by which a drug moves from the bloodstream to the body tissues.
- Factors influencing distribution:
- Blood flow
- Permeability of tissues
- Binding of drug to plasma proteins
- Presence of barriers: blood-brain barrier, placental barrier
Metabolism (Biotransformation)
- Process by which the body chemically alters a drug to facilitate its excretion.
- Primarily occurs in the liver, but also in the lungs, kidneys, and intestines.
- Factors influencing metabolism:
- Age
- Disease state
- Genetic factors
- Concomitant drug therapy
Excretion
- Process by which the body eliminates a drug.
- Primarily occurs through the kidneys, but also through the liver (bile), lungs, and intestines.
- Factors influencing excretion:
- Renal function
- Liver function
- pH of urine
- Drug reabsorption from the renal tubule
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on pharmacology concepts including pharmacokinetics and pharmacodynamics. This quiz will cover drug sources, nomenclature, and the process of drug administration. Perfect for students learning about the effects of drugs on the body and their mechanisms.
