Pharmacology Overview Quiz

Pharmacology

The study of drugs and their effects on living organisms, including classification, pharmacokinetics, pharmacodynamics, side effects, and therapeutic uses.
A drug is defined as a substance used to prevent, diagnose, treat, or cure diseases in animals and humans.

Pharmacokinetics

Describes the movement of a drug within the body; specifically absorption, distribution, metabolism, and excretion.

Pharmacodynamics

Studies the pharmacological and physiological effects of drugs, as well as the mechanisms of action of drugs.

Pharmacogenomics

The study of genetic variations that contribute to individual differences in drug responses.

Branches of Pharmacology

Medical pharmacology: Deals with the therapeutic and toxic effects of chemicals administered to patients.
Toxicology: Focuses on the undesirable effects of chemicals on living systems.

Pharmacokinetics of Drugs

Focuses on ADME (absorption, distribution, metabolism, and excretion of drugs)

Pharmacokinetic Pathways

Absorption: The process by which a drug enters the bloodstream from the site of administration.
Distribution: The process by which a drug travels throughout the body, moving from the bloodstream into various tissues and organs.
Metabolism (biotransformation): The process by which the body chemically alters a drug, often breaking it down into inactive metabolites.
Excretion: The process by which the body removes a drug and its metabolites from the body, primarily through urine, bile, or feces.

Onset of Action

The time it takes for a drug's effects to become noticeable after administration.
Can vary significantly, depending on the drug and route of administration.

Peak Time (tmax)

The time at which a drug reaches its maximum concentration in the bloodstream.

Routes of Drug Administration

Enteral: Drugs are administered via the gastrointestinal tract (GIT).
- Oral: Swallowed, allowing absorption from the stomach and duodenum.
- Sublingual: Placed under the tongue for direct absorption into the bloodstream.
- Rectal: Administered through the rectum.
Parenteral: Drugs are injected directly into the body, bypassing the digestive system.
- Intravascular: Injected directly into the bloodstream.
  - IV (intravenous): The drug is injected directly into a vein, allowing rapid absorption and distribution.
  - IM (intramuscular): The drug is injected into a muscle, allowing for gradual absorption into the bloodstream.
  - SC (subcutaneous): The drug is injected under the skin, allowing for slow, sustained absorption.
Other Routes:
- Inhalation: Inhaled drugs are rapidly absorbed across the large surface area of the respiratory tract.
- Intranasal: Drugs are administered through the nose.
- Topical: Drugs are applied directly to the skin or mucous membranes.
- Transdermal: Drugs are absorbed through the skin, typically via a patch.
- Intrathecal: Drugs are injected directly into the cerebrospinal fluid (CSF), bypassing the blood-brain barrier.
- Intraarticular: Drugs are injected directly into a joint space.

Oral Dosage Forms

Tablets: Solid dosage forms containing active ingredients.
Coated tablets: Tablets coated with a thin layer of substance, often sugar, to mask taste or improve disintegration in the stomach.
Enteric-coated tablets: Tablets coated with a substance that prevents dissolution in the stomach, designed to dissolve in the small intestine.
Capsules: Capsules contain active ingredients in a shell, usually made of gelatin, for easy swallowing.
- Hard gelatin capsules: Contain powders or granules.
- Soft gelatin capsules: Contain liquids or semi-solids.
Syrups: Liquid dosage forms containing active ingredients dissolved in a sweetened, flavored solution.
Suspensions: Liquid dosage forms containing active ingredients in a finely divided state, suspended in a liquid vehicle.

Advantages and Disadvantages of Different Routes

Oral:
- Advantages: Convenient, cost-effective, relatively safe.
- Disadvantages: First-pass metabolism, slower absorption, potentially affected by food, less predictable absorption.
Sublingual:
- Advantages: Rapid absorption, bypasses first-pass metabolism.
- Disadvantages: Not suitable for all drugs, limited dosage amounts.
Rectal:
- Advantages: Bypasses first-pass metabolism, useful for patients who can't swallow or are vomiting.
- Disadvantages: Irritation, unpredictable absorption.
IV:
- Advantages: Rapid onset of action, complete bioavailability (100% of the drug reaches circulation), precise control over dosage.
- Disadvantages: Risk of infection, pain, difficulty in reversing effects, potential for adverse reactions.
IM:
- Advantages: Moderate absorption rate, suitable for depot injections (extended release).
- Disadvantages: Potential for pain, injury to nerves or blood vessels.
SC:
- Advantages: Slower absorption than IV or IM, relatively safe for insulin injections.
- Disadvantages: Slow onset of action, risk of local irritation or infection.
Inhalation:
- Advantages: Rapid delivery, targets the respiratory system directly, minimizes systemic effects.
- Disadvantages: Requires proper technique, potential for respiratory irritation.
Topical:
- Advantages: Targets localized areas, minimal systemic effects.
- Disadvantages: Not effective for systemic conditions, limited absorption.
Transdermal:
- Advantages: Provides sustained release, bypasses first-pass metabolism, convenient.
- Disadvantages: Not for all drugs, slow onset of action, potential skin irritation.
Intrathecal:
- Advantages: Direct delivery to the CSF, bypasses the BBB.
- Disadvantages: Increased risk of complications, requires skilled administration.
Intraarticular:
- Advantages: Direct delivery to the joint space.
- Disadvantages: Risk of complications, potential for pain and inflammation.