18 Questions
What is the definition of pharmacology?
The study of drugs and their interactions with the living systems
What is the primary site of absorption for enteral routes of drug administration?
The gastrointestinal tract
What is the term for the process of a drug being broken down in the body?
Metabolism
What is the difference between pharmacokinetics and pharmacodynamics?
Pharmacokinetics deals with the body's effects on drugs, while pharmacodynamics deals with the effects of drugs on the body
What is the structure of the intestinal epithelium membrane?
Two layers of phospholipids with intermingled protein molecules
What is the term for the study of the absorption, distribution, metabolism, and excretion of drugs?
Pharmacokinetics
What is the primary mechanism by which drugs are absorbed from the site of administration into the bloodstream?
Passive diffusion and carrier mediated transport
What is the term for the metabolism of a drug during its passage from the site of absorption to the systemic circulation?
First pass metabolism
What is the fraction of the drug that reaches the blood circulation following administration by any route?
Bioavailability
What is the process by which substances are circulated from the liver to the bile, followed by entry into the small intestine, absorption by the enterocyte, and transport back to the liver?
Enterohepatic circulation
Why may the dose of some drugs need to be increased or the route of administration changed?
To compensate for first pass metabolism
What is the dispersal of drugs from the systemic circulation to other tissues and the site of action?
Distribution
What determines the rate and extent of distribution of a drug?
Multiple factors, including plasma protein binding and lipid solubility
Which type of drug binds mainly to albumin?
Acidic drugs
What is the only form of a drug available for action, metabolism, and excretion?
Free and unbound fraction
What is the result of protein binding on the duration of action of a drug?
It prolongs the duration of action of the drug
What is the primary mechanism of crossing the blood-brain barrier?
Only lipid soluble unionised drugs can cross
What is the volume of distribution of a drug?
The extent of distribution of a drug in the body compared to plasma
Study Notes
Pharmacology and Pharmacokinetics
- Pharmacology: the study of drugs and their interactions with the living systems.
- Pharmacokinetics: the effect of the body on the drug, involving absorption, distribution, metabolism, and excretion of drugs.
- Pharmacodynamics: the effects of the drugs on the body and their mechanism of action.
Routes of Drug Administration
- Enteral routes: oral (by mouth), buccal (via the cheeks), sublingual (under the tongue), rectal (via the anus)
- Parenteral routes: intravenous (IV), intramuscular (IM), subcutaneous (SC), intrathecal (IT), intraperitoneal (IP)
- Topical routes: transdermal, vaginal (transcutaneous absorption)
Absorption
- Absorption: the movement of a drug from its site of administration into the bloodstream
- Factors influencing absorption: passive diffusion, carrier-mediated transport, membrane composition, and surface area
- First-pass metabolism: metabolism of a drug during its passage from the site of absorption to the systemic circulation
- Drug bioavailability: the fraction of the drug that reaches the blood circulation following administration by any route
- IV administration: 100% bioavailability
Distribution
- Distribution: dispersal of drugs from the systemic circulation to the other tissues and the site of action
- Factors determining distribution: plasma protein binding, molecular weight, lipid solubility, ionization, blood flow, and cellular proteins
- Plasma protein binding: affects the free and unbound fraction of the drug available for action, metabolism, and excretion
- Blood-brain barrier: a protective barrier for the brain, only allowing lipid-soluble, unionized drugs to cross
- Placental barrier: lipid-soluble, unionized drugs readily cross the placenta, while lipid-insoluble drugs cross to a lesser extent
- Volume of distribution: describes how extensively drugs are distributed to the rest of the body compared to plasma, and may distribute into multiple compartments
Test your understanding of the fundamental principles of pharmacology, including drug administration, absorption, distribution, metabolism, and excretion. Learn about the interactions between drugs and living systems. This quiz covers the basics of pharmacokinetics, perfect for students in pharmacy or medical school.
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