PHR-LEC-REVIEWERS.docx

### Module 1: Introduction to Pharmacology and Drugs #### Lesson 1: Fundamental Concepts of Pharmacology - **Pharmacology**: Study of drug properties, effects on living systems. - **Pharmacogenetics**: Examines genetic factors influencing drug responses. - **Pharmacognosy**: Study...

### Module 1: Introduction to Pharmacology and Drugs #### Lesson 1: Fundamental Concepts of Pharmacology - **Pharmacology**: Study of drug properties, effects on living systems. - **Pharmacogenetics**: Examines genetic factors influencing drug responses. - **Pharmacognosy**: Study of drugs derived from natural sources. - **Pharmacy**: Science of preparing and dispensing medicines. - **Toxicology**: Study of harmful effects of drugs. - **Posology**: Study of drug dosage in disease treatment. #### Terms Related to Drug Effects: - **Therapeutic effect**: Desired outcome of a drug. - **Side effect**: Unintended secondary effects. - **Drug Allergy**: Immune reaction to a drug. - **Anaphylactic Reaction**: Severe allergic response post-drug administration. - **Drug Tolerance**: Decreased response to repeated drug use. - **Cumulative Effect**: Increased drug effect with repeated doses. #### Drug Misuse and Dependence: - **Drug Abuse**: Improper intake of substances. - **Drug Dependence**: Need for drug use, potentially leading to **Addiction** (physical dependence). - **Habituation**: Emotional dependence on a drug. #### Drug Interactions: - **Antagonism**: One drug decreases the effect of another. - **Synergism**: Two drugs together have a greater effect than individually. - **Potentiation**: One drug enhances the effect of another. #### Therapeutic Actions: - **Palliative**: Relieves symptoms, doesn't cure. - **Curative**: Treats the underlying disease. - **Supportive**: Maintains body functions during treatment. - **Substitutive**: Replaces missing substances in the body. ### Lesson 2: Major Areas of Pharmacology #### Pharmacokinetics: - **Absorption**: Drug enters bloodstream. Factors: blood flow, pain, solubility, pH, dosage form. - **Distribution**: Drug reaches tissues. Influenced by circulation, membrane permeability, plasma protein binding. - **Metabolism**: Drug is transformed, mainly in the liver. - **Excretion**: Drugs are removed, primarily by the kidneys. #### Pharmacodynamics: - **Mechanism of Action (MOA)**: How a drug works in the body. - **Indication**: The drug's intended use. - **Contraindication**: When a drug shouldn't be used. - **Agonists**: Stimulate responses at receptors. - **Antagonists**: Block or reduce responses at receptors. #### Onset, Peak, and Duration: - **Onset**: Time to reach minimum effective concentration. - **Peak**: Highest concentration in blood. - **Duration**: Time the drug has an effect. ### Lesson 3: Principles of Drug Administration #### 10 Rights of Medication Administration: 1. **Right Client**: Verify the patient's identity. 2. **Right Medication**: Check prescriptions and labels. 3. **Right Dose**: Ensure correct dose. 4. **Right Time**: Administer at the appropriate time. 5. **Right Route**: Use the proper administration method. 6. **Right Documentation**: Record details post-administration. 7. **Right Education**: Inform the patient about the medication. 8. **Right to Refuse**: Respect patient refusal and document it. 9. **Right Assessment**: Gather necessary data before/after administration. 10. **Right Evaluation**: Check for therapeutic and adverse effects. #### Sources of Drug Information: - Drug handbooks, medical journals, nursing journals, package inserts, and more. #### Legal Aspects: - **Controlled Substances Act (1970)**: Classifies drugs based on abuse potential. - **Generics Act (Philippines, 1988)**: Promotes use of generic drug names. - **Cheaper Medicines Act (Philippines, 2008)**: Focuses on affordable medication access. ### Module 2: Drugs Acting on the Respiratory System #### Lesson 1: Antihistamines & Antitussives ##### Antihistamines - **Function**: Block H1 receptors to decrease nasopharyngeal secretions, treating colds and allergic rhinitis. - **Types**: - **1st Generation**: Causes drowsiness and anticholinergic effects (e.g., **diphenhydramine**). - **2nd Generation**: Less sedation, fewer anticholinergic effects (e.g., **cetirizine**, **fexofenadine**, **loratadine**). ##### Antihistamines Pharmacokinetics: - **Diphenhydramine**: Absorbed from the GI tract; highly protein-bound; metabolized in the liver; excreted in urine. - **Onset**: 15 minutes (oral), immediate (IV/IM). - **Duration**: 4-8 hours. ##### Side Effects: - **1st Generation**: Drowsiness, dizziness, dry mouth, urinary retention, blurred vision. ##### Antitussives - **Function**: Suppress coughing by acting on the medulla\'s cough center. Indicated for nonproductive cough. - **Types**: - **Nonnarcotic**: **Dextromethorphan**. - **Narcotic**: **Codeine**, **Hydrocodone**. - **Combination Preparations**: Both nonnarcotic and narcotic. ##### Pharmacokinetics of Dextromethorphan: - **Absorption**: Rapid; effects begin in 15-30 minutes. - **Metabolism**: Liver; excreted via kidneys. ##### Pharmacodynamics: - **Dextromethorphan**: Suppresses the cough reflex without depressing respiration. - **Benzonatate**: Anesthetizes stretch receptors in the respiratory system. - **Codeine and Hydrocodone**: Act on the medulla's cough center. ##### Drug Interactions: - **Codeine and Hydrocodone**: Can cause dangerous reactions when used with monoamine oxidase inhibitors (MAOIs) or other CNS depressants. #### Lesson 2: Asthma Drugs ##### Methylxanthines (Theophylline) - **Function**: Bronchodilator used for chronic stable asthma and COPD by increasing cAMP levels, leading to bronchodilation. - **Therapeutic Range**: 10-20 mcg/mL. ##### Pharmacokinetics: - Absorbed well after oral administration; metabolized by liver; excreted by kidneys. - **Half-life**: Varies by smoking status, age, and health condition (e.g., smokers: 4-5 hours; non-smokers: 7-9 hours). ##### Side Effects: - Common: Nausea, vomiting, headache, dizziness, tachycardia. - Severe: Cardiac dysrhythmias, seizures. ##### Drug Interactions: - Avoid caffeinated products due to increased diuretic effects. - Rapid IV administration can cause severe hypotension and bradycardia. ##### Other Bronchodilators: - **Pirbuterol**: Beta-2 adrenergic receptor agonist; side effects include nervousness, tremors, headache, palpitations. - **Cromolyn Sodium**: Prevents histamine release and used for preventing bronchial asthma, not for acute attacks. #### Lesson 3: Mucolytics and Expectorants ##### Mucolytics - **Function**: Liquefy and loosen thick mucus secretions to ease expectoration. - **Example**: **Acetylcysteine**. - Used via nebulization and may be combined with bronchodilators. - Side effects: Nausea, vomiting, runny nose, stomatitis. ##### Acetylcysteine as Antidote: - Can be used as an antidote for acetaminophen overdose if administered within 12-24 hours. ##### Expectorants - **Function**: Loosen bronchial secretions, allowing them to be expelled more easily by coughing. - **Example**: **Guaifenesin**. - Hydration enhances the expectorant effect. - Side effects: Nausea, vomiting, diarrhea. ##### Pharmacodynamics: - **Guaifenesin**: Increases respiratory fluid production, reducing mucus thickness and adhesiveness, aiding its clearance. ##### Indications: - Used to relieve coughs from bronchitis, sinusitis, asthma, and respiratory infections. ### Module 3: Drugs Acting on the Cardiovascular System #### 1. Cardiotonic Drugs - **Cardiac Glycosides**: - Mechanism: Inhibits sodium-potassium pump, increasing intracellular calcium. - Effects: Positive inotropic (increased myocardial contractility), negative chronotropic (slowed heart rate), and negative dromotropic (slower conduction through AV node). - Uses: Treats atrial fibrillation and atrial flutter by improving cardiac output and kidney function, reducing edema. - **Digoxin (Lanoxin)**: - - - #### 2. Phosphodiesterase Inhibitors - **Mechanism**: Inhibit phosphodiesterase, increase calcium influx, improve cardiac output, and reduce afterload. - **Drugs**: Inamrinone, Milrinone. - Administered intravenously for acute heart failure; closely monitored due to the risk of severe dysrhythmias. - Drug Interactions: May reduce serum potassium, leading to hypokalemia when combined with potassium-wasting diuretics. #### 3. Antianginal Drugs - **Nitrates**: - Mechanism: Vasodilation of coronary arteries, reduces myocardial ischemia. - Forms: Sublingual (rapid absorption), topical, buccal, IV, aerosol spray. - Side Effects: Headaches, dizziness, hypotension. Risk of reflex tachycardia if administered too quickly. - **Beta Blockers**: - Mechanism: Block beta-adrenergic receptors, reducing heart rate and oxygen demand. - Drugs: Propranolol (non-selective), Atenolol, Metoprolol (selective). - Uses: Anti-anginal, antihypertensive, and antidysrhythmic. - Side Effects: Bronchospasm (non-selective), bradycardia, impotence. - **Calcium Channel Blockers**: - Mechanism: Relax coronary arteries, reduce afterload, decrease cardiac oxygen demand. - Drugs: Verapamil, Nifedipine, Diltiazem. - Side Effects: Hypotension, reflex tachycardia, liver and kidney function changes. #### 4. Antihypertensive Drugs - **Sympatholytic Drugs**: - Mechanism: Inhibit sympathetic nervous system, causing vasodilation and reduced cardiac output. - Drugs: Clonidine, Alpha blockers (Prazosin), Beta blockers, and Mixed Alpha-Beta blockers (Labetalol). - Side Effects: Hypotension, depression, drowsiness, liver dysfunction. - **Vasodilators**: - Mechanism: Directly relax vascular smooth muscle, reducing blood pressure. - Drugs: Hydralazine, Minoxidil, Nitroprusside. - Side Effects: Reflex activation of the sympathetic nervous system, leading to adverse reactions. - **ACE Inhibitors**: - Mechanism: Block RAAS (renin-angiotensin-aldosterone system), reducing blood pressure. - Drugs: Captopril, Enalapril, Lisinopril. - Side Effects: Persistent cough, hyperkalemia, hypotension. - Drug Interactions: Potassium-sparing diuretics may lead to hyperkalemia. #### 5. Antidysrhythmic Agents - **Class I: Sodium Channel Blockers**: - Mechanism: Decrease sodium influx, slow conduction velocity, and suppress automaticity. - Drugs: Quinidine (IA), Lidocaine (IB), Flecainide (IC). - Side Effects: Hypotension, neurological symptoms (e.g., confusion), cardiovascular depression. - **Class II: Beta Blockers**: - Mechanism: Decrease automaticity and myocardial excitability. - Drugs: Propranolol, Esmolol. - Used more frequently than Class I drugs. - **Class III: Drugs that Prolong Repolarization**: - Mechanism: Increase refractory period and action potential duration. - Drugs: Amiodarone, Bretylium. - **Class IV: Calcium Channel Blockers**: - - - ### Module 4: Drugs Acting on the Hematologic System #### 1. Hematinic Drugs - **Purpose**: Provide building blocks for red blood cell (RBC) production, essential for hemoglobin synthesis, which is necessary for oxygen transportation. - **Iron**: - **Indications**: Treats Iron Deficiency Anemia (IDA). - **Common Forms**: Ferrous sulfate, ferrous gluconate, iron dextran (parenteral). - **Pharmacokinetics**: Absorbed in the duodenum and jejunum. - **Pharmacodynamics**: Used for hemoglobin production and erythropoiesis. - **Adverse Reactions**: Gastric irritation, darkened stool, and stained teeth from liquid forms. - **Drug Interactions**: Decreased absorption with antacids and certain antibiotics. - **Vitamin B12**: - **Indications**: Treats pernicious anemia. - **Common Forms**: Cyanocobalamin and hydroxocobalamin. - **Pharmacodynamics**: Replaces vitamin B12, which is vital for RBC production. - **Folic Acid**: - **Indications**: Treats folic acid deficiency; used preventively during pregnancy and conditions like hemolytic anemia and liver disease. - **Pharmacokinetics**: Absorbed in the small intestine, metabolized in the liver, excreted through urine and stool. - **Epoetin Alfa**: - **Indications**: Stimulates RBC production in patients with chronic renal failure and HIV-related anemia. - **Pharmacodynamics**: Boosts erythropoietin production. - **Adverse Reactions**: Hypertension, headache, nausea, dizziness. #### 2. Anticoagulant Drugs - **Heparin**: - **Indications**: Prevents and treats venous thromboembolism and arterial clotting (e.g., in atrial fibrillation). - **Pharmacodynamics**: Inhibits thrombin and fibrin formation by activating antithrombin III, preventing stable fibrin clot formation. - **Administration**: Given parenterally (IV or subcutaneous). - **Adverse Reactions**: Bleeding, reversible with protamine sulfate. - **Drug Interactions**: Increased risk of bleeding when taken with NSAIDs and oral anticoagulants. - **Oral Anticoagulants (e.g., Warfarin)**: - **Indications**: Treats thromboembolism and prevents deep vein thrombosis (DVT). - **Pharmacodynamics**: Inhibits vitamin K-dependent clotting factors. - **Adverse Reactions**: Bleeding. - **Drug Interactions**: Enhanced bleeding risk with aspirin and NSAIDs. - **Antiplatelet Drugs**: - **Drugs**: Aspirin, dipyridamole, sulfinpyrazone, ticlopidine. - **Pharmacodynamics**: Prevent platelet aggregation (e.g., aspirin inhibits thromboxane A2 formation). - **Indications**: Used in patients at risk for myocardial infarction (MI), stroke, and arteriosclerosis. - **Drug Interactions**: Increased bleeding risk when combined with other anticoagulants or NSAIDs. #### 3. Thrombolytic Drugs - **Mechanism**: Converts plasminogen to plasmin, dissolving thrombi, fibrinogen, and other plasma proteins. - **Drugs**: - **Alteplase**: Used for acute MI, pulmonary embolism, and ischemic stroke. - **Anistreplase**: Used for acute MI. - **Streptokinase**: Used for MI, pulmonary embolism, DVT. - **Pharmacokinetics**: Rapid IV distribution, cleared by the liver or plasma. - **Drug Interactions**: Increased bleeding risk when combined with anticoagulants and NSAIDs. - **Adverse Reactions**: Bleeding and allergic reactions (especially with streptokinase). #### 4. Antilipemic Drugs - **Bile-Sequestering Drugs**: - **Drugs**: Cholestyramine, colestipol. - **Pharmacodynamics**: Lowers LDL cholesterol by binding bile acids in the intestines. - **Adverse Reactions**: Reduces the absorption of lipid-soluble vitamins and other drugs. - **Fibric Acid Derivatives**: - **Drugs**: Clofibrate, gemfibrozil. - **Pharmacodynamics**: Reduces cholesterol production, mobilizes cholesterol from tissues, and increases HDL levels. - **Indications**: Primarily used to reduce triglycerides and cholesterol levels. - **Drug Interactions**: Increases risk of bleeding with oral anticoagulants, can displace acidic drugs. - **Cholesterol Synthesis Inhibitors (Statins)**: - **Drugs**: Lovastatin, pravastatin, simvastatin. - **Pharmacodynamics**: Inhibits cholesterol synthesis in the liver. - **Indications**: Used to treat elevated total cholesterol and LDL levels. - **Adverse Reactions**: Gastrointestinal disturbances, headache, liver enzyme elevation. - **Drug Interactions**: Increased risk of myopathy when combined with immunosuppressants, gemfibrozil, or erythromycin.