Introduction to Pharmacology

Introduction to Pharmacology

• Pharmacology is the study of drugs and their interactions with living organisms.
• It encompasses drug discovery, development, mechanisms of action, pharmacokinetics, and pharmacodynamics.
• Discovering drugs involves identifying molecules with therapeutic potential.
• Developing drugs includes preclinical and clinical trials to assess safety and efficacy.
• Pharmacokinetics describes how the body handles drugs (absorption, distribution, metabolism, and excretion).
• Pharmacodynamics describes the effects of drugs on the body (receptor interactions, signaling pathways).

Drug Classification

• Drugs are classified by their therapeutic use, chemical structure, mechanism of action, or target receptor.
• Examples include analgesics, antibiotics, antihypertensives, and antipsychotics.
• Each class has specific therapeutic uses and mechanisms of action.
• Classifications can overlap; a drug can be both an analgesic and an NSAID.

Drug Action Mechanisms

• Drugs affect specific targets like receptors, enzymes, or ion channels.
• Drugs are agonists, antagonists, or allosteric modulators.
• Agonists activate receptors; antagonists block activation.
• Allosteric modulators alter receptor function.
• Drug effect depends on concentration and target sensitivity.

Pharmacokinetics

• Absorption: Drugs enter the bloodstream.
• Absorption factors: route of administration, drug solubility, food/substances.
• Distribution: Drug transport throughout the body.
• Distribution factors: blood flow, protein binding, tissue permeability.
• Metabolism: Drug transformation into active or inactive forms.
• Primary site of metabolism: liver.
• Excretion: Drug removal from the body.
• Main excretion route: kidneys.
• Other routes: feces, bile, lungs.

Pharmacodynamics

• Drug effects on the body – mechanisms of these effects.
• Drug-receptor interactions are crucial in pharmacodynamics.
• Receptors are protein drug targets, classified by function.
• Agonists and antagonists affect receptor activity.

Drug Toxicity and Adverse Effects

• Drugs can cause variable adverse effects, ranging in severity.
• Adverse effects can be dose-dependent or idiosyncratic.
• Severe adverse effects are toxic, causing harm.
• Adverse effect monitoring and management are vital for safe drug use.

Drug Interactions

• Drugs can interact, altering their effects.
• Interactions can result in increased or decreased efficacy or adverse effects.
• Factors influencing interactions: drug concentration, route of administration, other factors.

Ethical Considerations in Drug Development and Use

• Ethical considerations are integral throughout drug development, from preclinical to clinical trials.
• Ethical guidelines ensure patient safety and rights.
• Informed consent and patient confidentiality are essential for ethical drug use.
• Clinical trials must meet strict ethical standards.

Specific Areas of Pharmacology

• Cardiovascular Pharmacology: Drugs affecting the heart and blood vessels (e.g., antihypertensives, antiarrhythmics).
• Neuropharmacology: Drugs affecting the nervous system (e.g., antidepressants, antipsychotics).
• Oncology Pharmacology: Drugs used in cancer treatment.
• Immunopharmacology: Drugs affecting the immune system (e.g., immunosuppressants, immunomodulators).
• Clinical pharmacology: Applying pharmacology principles to treat diseases.

Types of Drugs

• Over-the-counter (OTC) drugs: Available without a prescription.
• Prescription drugs: Require a prescription from a physician.