Pharmacology Overview and Drug Classifications

Pharmacology

• The study of how drugs affect living tissue and how those chemicals prevent and diagnose disease.
• Also, the study of drug mechanisms of action.
• It encompasses what drugs do to the body and how drugs move through the body.
• It also covers how the body responds to drugs.

Drug Classifications

• Prophylactic/Preventive: Prevents disease.
• Diagnostic: Helps detect the cause of disease.
• Therapeutic:
  • Curative: Treats diseases.
  • Palliative: Does not treat the disease itself but manages symptoms.
  • Supportive: Helps sustain the patient.
  • Substitutive: Replaces a missing substance.
  • Restorative: Helps the body return to its normal healing state.
• Prescription Drugs: Ordered by a physician.
• Non-Prescription Drugs/Over-the-Counter Drugs: Available without a prescription.
• Investigational Drugs: Drugs under investigation, not yet approved.
• Illicit Drugs/Illegal Drugs: Abused drugs.

Drug Names

• Official Name: Listed in official drug references.
• Chemical Name: Describes the drug's chemical structure.
• Generic Name: Not owned by any drug company.
• Proprietary Name/Brand Name: Trademarked by the manufacturer.

Drug Development

• Requires extensive research on how drugs work.
• Undergoes three stages of clinical trials before FDA approval:
  • Pre-clinical Trials: Tested on animals.
  • Phase I: Tested on 20-80 volunteers for about a year.
  • Phase II: Tested on 100-300 volunteers for about two years.
  • Phase III: Tested on 1000-3000 patients in clinics and hospitals for about three years.
• Takes approximately 2.5 years for FDA approval.

Pregnancy Categories (1979)

• Defined potential risks of birth defects from drugs during pregnancy.
  • Category A: Safe for use in pregnancy.
  • Category B: Safe in animals, but no human studies.
  • Category C: Adverse effects observed in animal studies, limited human data.
  • Category D: Adverse effects in humans, benefits outweigh risks.
  • Category X: Risks outweigh benefits, causes abortion.

Pregnancy and Lactation Labeling Final Rule (PLLR)

• Replaced pregnancy categories in 2015.
• Removed by 2018.

Relevant Drug Laws

• Generic Act of 1988 (RA 6675): Ensures production of an adequate drug supply.
• Administrative Order No. 62 S. 1989: Implements rules and regulations for prescribing, including using generic names in all prescriptions.

Prescription Parts

• Superscription: Heading with the symbol Rx.
• Inscription: Body of the prescription, containing the drug name and dosage.
• Subscription: Directions for the pharmacist.
• Signature: Specific instructions for the patient.
• Order Types:
  • Single order: Given once.
  • PRN order: As needed.
  • STAT order: Immediately.

Antiarrhythmic Drugs

• Used to restore a normal cardiac rhythm.

Cardiac Dysrhythmias

• Prinzmetal Angina

Niacin (Vitamin B3)

• Effective in lowering cholesterol levels.

Anticoagulants

• Prevent blood clot formation.
  • Venous Problems: Deep vein thrombosis (DVT).
  • Arterial Problems: Coronary thrombosis or myocardial infarction (MI).

Anticoagulant Classifications

• Heparin (Heparin Sodium): Natural liver substance introduced in 1938.
  • Used to prevent clotting in blood transfusions and open heart surgery.
• Low-Molecular-Weight Heparins: Introduced to prevent venous thromboembolism.
  • Inhibits factor Xa, but less effective in inactivating thrombin.
  • Examples: Enoxaparin sodium, Dalteparin sodium.
• Fondaparinux: Once-daily subcutaneous (SQ) injection.
• Direct Thrombin Inhibitors: Directly inhibit thrombin's conversion of fibrinogen to fibrin.
  • More expensive than other anticoagulants.
  • Examples: Argatroban, Bivalirudin, Lepirudin, Desirudin, Dabigatran.
• Oral Anticoagulants:
  • Warfarin: Oral anticoagulant from the coumarin family.
    • Inhibits Vitamin K synthesis in the liver, affecting clotting factors II, VII, IX, and X.
  • Factor Xa Inhibitors: Block clotting factor Xa activity.
    • Examples: Rivaroxaban, Apixaban, Edoxaban.

Thrombolytics

• Break down existing blood clots.

Histamine Antagonists

• Compete with histamine for receptor sites, preventing histamine responses.
  • Decrease nasopharyngeal secretions by blocking H1 receptors.

Antihistamines

• First-Generation Antihistamines:
  • Anticholinergic properties, causing dryness of mouth and decreased secretions.
  • Examples: Brompheniramine maleate, Chlorpheniramine maleate, Clemastine fumarate, Diphenhydramine, Cyproheptadine HCl, Levocitirizine (Xyzal), Chlorcyclizine.
• Second-Generation Antihistamines:
  • Non-sedating, little to no effect on sedation.
  • Examples: Azelastine, Cetirizine, Fexofenadine, Loratadine, Desloratadine.

Nasal and Systemic Decongestants

• Nasal Decongestants: Stimulate alpha-adrenergic receptors, constricting nasal capillaries.
• Systemic Decongestants (Alpha Adrenergic Agonists):
  • Used for allergic rhinitis.
  • Longer-lasting relief than nasal decongestants.
  • Examples: Ephedrine, Phenylephrine, Phenylpropanolamine, Pseudoephedrine, Oxymetazoline, Naphazoline, Tetrahydrozoline.

Intranasal Glucocorticoids

• Effective for treating allergic rhinitis or hay fever.
• Examples: Beclomethasone, Budesonide, Flunisolide, Fluticasone, Triamcinolone.

Antitussives

• Suppress the cough reflex by acting on the cough control center in the medulla.
• Used for non-productive and irritating coughs.
• Types:
  • Narcotic Antitussives:
    • Examples: Codeine, Dextromethorpan, Homatropine and Hydrocodone, Guaifenesin and codeine.
  • Non-Narcotic Antitussives:
    • Do not depress respiration.
    • Examples: Benzonatate.

Expectorants

• Loosen bronchial secretions for coughing.
• Example: Guaifenesin.

Drugs for Acute and Chronic Lower Respiratory Disorders

• Bronchodilators: Dilate bronchioles to improve airflow.
  • Sympathomimetics:
    • Increase cAMP, causing bronchodilation.
    • cAMP: Cyclic adenosine monophosphate, activates target enzymes in cells.
    • Examples: Albuterol, Metaproterenol, Isoproterenol, Levalbuterol, Salmeterol, Terbutaline Sulfate, Arformoterol, Indacaterol, Olodaterol.
  • Methylxanthines:
    • Used for asthma treatment.
    • Examples: Aminophylline, Theophylline (maintenance), Doxophylline.
  • Anticholinergics:
    • Dilate bronchi and decrease bronchial secretions.
    • Examples: Ipratropium bromide, Glycopyrrolate, Aclidinium, Tiotropium.

This quiz covers the fundamental concepts of pharmacology, focusing on how drugs affect living tissues, their classifications, and types. Participants will explore various drug classifications such as prophylactic, therapeutic, and prescription drugs, gaining a deeper understanding of their roles in disease prevention and treatment.