Pharmacology Basics Quiz

Introduction

• Medication is a chemical compound or substance used for diagnosis, prevention, cure, or treatment of diseases, or to relieve symptoms. It affects physiological functions in living organisms.
• A prescription is a written direction for preparing and administering a drug. It includes the patient's name, medication name, dose, route, frequency, amount of medication, doctor's signature, and more.
• Nonprescription/OTC medication can be purchased without a prescription. It's used to promote health or treat mild health problems.
• Pharmacology is the study of how drugs affect the functions of living systems.
• A pharmacy is the place where drugs are prepared, compounded, and dispensed.
• A pharmacist prepares, makes and dispenses drugs as ordered by a physician/dentist.

Sources of Drugs

• Drugs can be natural, semisynthetic, or synthetic.
• Plants (e.g., foxglove - digoxin)
• Animals (e.g., pregnant mare serum - conjugated estrogens)
• Micro-organisms (e.g., Penicillium mold - penicillin)
• Minerals (e.g., iron)
• Synthetic chemistry
• Genetic engineering (e.g., insulin)

Drug Names

• Chemical name: Describes the drug's atomic/molecular structure and functional groups; rarely used clinically.
• Generic name: Assigned by regulatory bodies (e.g., United States Adopted Names Council); used globally throughout the drug's life cycle; typically unique to a drug.
• Brand name/Trade name/Proprietary name: Given by the manufacturer; used for marketing purposes; often short and easily remembered. One drug may have several brand names.

Brand vs Generic Drugs

• No difference in active ingredients, strength, or dosage
• Brand names may be more expensive
• Insurance coverage may vary
• FDA testing and approval applies to both

Pharmacokinetics

• Pharmacokinetics describes what the body does to the drug:
• Absorption: passage of drug into the bloodstream.
• Distribution: transport of the drug to various parts.
• Metabolism (biotransformation): modifying drugs chemically in the body (often detoxifying).
• Excretion: elimination of the drug from the body.

Drug Absorption

• Absorption is the process of drugs entering the bloodstream.
• Drugs must be administered in the correct form and via the correct route.
• Administration directly into veins/arteries results in the greatest absorption rate.

Bioavailability (BA)

• Bioavailability is the percentage of a drug that reaches the systemic circulation and can access its target site.
• Intravenous (IV) administration results in complete bioavailability.
• Absorption rate and extent are influenced by factors such as drug nature and administration route.

First-Pass Metabolism

• Oral medication is absorbed from the gastrointestinal tract (GI) via the hepatic portal vein to the liver.
• The liver metabolizes, or destroys many drugs, reducing the bioavailability of active drugs reaching their site of action.
• Some oral drugs are partially metabolized in the liver before reaching the target organ, resulting in the need for higher oral doses.

Drug forms

• Specific drug forms are employed to release the drug at the desired speed.
• Examples include tablets, capsules, suppositories, transdermal patches, and solutions.
• Slow-release tablets may lead to reduced absorption.
• Drugs must be dissolved in solution before being absorbed.

Drug Distribution

• Drug distribution is the process of drug movement from the systemic circulation to the target site in the body.
• Organs with extensive blood supply (e.g., liver, kidneys, heart, brain) receive drugs more rapidly than those with less blood supply.
• Drugs cross capillary walls and cell membranes in order to reach their sites of action.

Plasma Proteins Binding

• Drug molecules can bind to plasma proteins, often becoming inactive.
• Only unbound drugs can bind to receptor sites and produce a physiological effect.
• Highly protein-bound drugs require higher doses to achieve therapeutic effects.

Drug Metabolism

• Biotransformation, or drug metabolism, is the chemical alteration of drugs and other foreign substances to the body.
• Involves enzymatic reactions that convert drugs into more watersoluble forms for easier excretion by the kidneys.
• Development changes, like immature livers in infants or decreased liver function in older adults, affect drug metabolism.

Drug Excretion

• Drug excretion is the removal of drugs from the body.
• Kidney function is crucial for excreting many drugs through urine.
• Other routes of excretion include the GI tract (bile), lungs, and exocrine glands.

Drug Half-Life

• Drug half-life is the time needed to eliminate one-half of the drug from the body.
• Repeated doses are needed to maintain a constant level.
• Factors like absorption, metabolism, and excretion influence half-life.

Loading Dose & Maintenance Dose

• A loading dose is a high initial dose given at the start of a drug regimen to quickly achieve a therapeutic level.
• A maintenance dose is a smaller subsequent dose administered regularly to maintain the therapeutic level.

Peak Plasma Levels

• Peak plasma level is the highest concentration of a drug in the blood after administration.
• Reaches a peak when absorption rate equals elimination rate.

Pharmacodynamics

• Pharmacodynamics explains what the drug does to the body.
• The mechanism of action (MOA) relates to drug-receptor interactions.
• Agonists activate receptors, while antagonists block them.

Receptors

• Receptors are the drug's specific target (like a lock-and-key mechanism).
• Binding to receptors is usually reversible; drug action stops when the drug detaches from the receptor.
• Drug effects result from interactions with receptor sites.

Agonists and Antagonists

• Agonists stimulate receptors to produce an effect similar to their endogenous counterparts.
• Antagonists block receptors, preventing the effects of endogenous substances or agonist drugs.