Pharmacology Exam Review PDF

Pharmacology Exam Review WHAT IS PHARMACOLOGY? The study of drugs. LECTURE 1 DEFINITIONS TO KNOW Unit 1 Package 1: Action and Effects of Medication Unit 1 Package 1: Action and Ef...

Pharmacology Exam Review WHAT IS PHARMACOLOGY? The study of drugs. LECTURE 1 DEFINITIONS TO KNOW Unit 1 Package 1: Action and Effects of Medication Unit 1 Package 1: Action and Effects of Medication Drug Action Terminology Review Drug Effect Terminology Review 1. Site of Action: location within the body where the drug exerts 1. Therapeutic Effect - desired effect, reason drug was prescribed its therapeutic effect i. Curative - cures a disease or condition (antibiotics) 2. Mechanism of Action: how the drug produces its effect ii. Palliative - relieves symptoms, does not affect the progress of 3. Receptor Site: specific point of attachment of drug on cell the disease itself (analgesics) membrane, this attachment initiates a series of biochemical iii. Chemotherapeutic - destroys malignant cells (cancer) changes that lead to drug action iv. Restorative - returns the body to health (vitamins) 4. Agonist: drugs that bind to specific receptor sites and produce 1. Cumulative Effect - the buildup of drug in the body, sometimes a drug action due to impaired and/or excretion 5. Antagonist: drugs that bind to specific receptor sites but do 2. Local Effect - localized effect not distributed systemically (local not produce any drug action, act as a barrier to that receptor site anesthetics, creams, ointments) 6. Affinity: degree of attraction or attachment of a drug to a 3. Systemic Effect - effects occur throughout the body in various receptor site tissues, drug carried through blood system 7. Dose Response Curve: graphed curve that correlates the 4. Drug Tolerance - patient has low physiological response to a dose (amount of drug) given to drug, usually due to prolonged use, and requires increased dosage the response produced, used to predict safe doses to maintain therapeutic response 8. Time Response Curve: relationship of drug response and 5. Allergic Reaction - immunological reaction to drug exposure, duration of action, onset of action, termination of action, used to where a patient responds to drug as an antigen and produces predict dosing times antibodies, reaction may be mild to severe. 9. Half Life: the amount of time it takes for half of the original 6. Idiosyncratic Response – individual - unexpected response, dose that was absorbed to be excreted particular patient may underrespond, overrespond, or 10. Bioavailability: percentage of the drug dosage that is demonstrate unexplained symptoms absorbed and available for biological use 7. Toxic Effect - deleterious effect from drug in a body tissue or 11. Blood Drug Level/Concentration: the amount of drug organ, caused by too much drug present in the plasma 8. Teratogenic Effect - capable of causing fetal malformation, Drug action: activity of the drug at the cellular site (binding site) birth defects (cleft palate) Drug effect: Biological effect of the drug within the body, 9. Iatrogenic Effect - disease/condition that has been caused by therapeutic effect, side effect, adverse effect and toxic effect. medical therapy Subcategories within Pharmacology Pharmacokinetics Pharmaco-therapeutics: study of drugs in treatment of disease The movement/life cycle of the drug through the body: Pharmacodynamics: study of the actions of drugs on living tissues ✓ Absorption Pharma-cokinetics: study of the processes of drug absorption, ✓ Distribution distribution, metabolism and excretion (ADME) ✓ Metabolism Toxicology: the study of harmful effects of drugs on living tissues ✓ Excretion Posology: the study of the amount of drug that is required to produce therapeutic effects Drug Absorption Absorption & Passive Transport The entrance of drug into the bloodstream. Three factors that influence passive transport Drug: 1. lipid solubility of the drug, ✓ Must be dissolved in body fluids 2. the degree of ionization of drug, ✓ With the exception of drugs given IV or via arteries, drugs must 3. drug formulation. then pass through cell membranes. HOW? Cell membranes 1. Lipid Solubility – the greater the lipid solubility of the drug, ✓ composed of protein and lipid and form a semi-permeable the quicker the rate of absorption barrier. 2. Degree of Ionization – if more ionized, more “charged”, and ✓ Drugs pass through cell membranes via filtration, passive harder to pass through transport, or active transport. 3. Drug Formulation – drugs must be in solution to be Most drugs pass through by passive transport. absorbed, drug should be in smallest particle size possible to be in solution and be absorbed, smaller size equals quicker absorption Drug Distribution Drug Metabolism ▪ After absorption, a drug is distributed to various tissues and After distribution (or during) drugs are metabolized: organs. Converted to forms that are useful ▪ Distribution is affected by plasma protein binding of the drug, and/or blood flow, and any specific tissue barriers. Converted to forms that are excreted Drug Distribution Factors Metabolism, aka biotransformation, usually occurs in the liver A. Plasma Protein Binding – only free drug can exert and under the process of oxidation/reduction pharmacological effects, bound drug to albumin and globulin (cytochrome P450 system = enzymes) provides a reserve pool of drug So, how does liver disease affect medications? B. Blood Flow – well perfused organs (liver, kidney, brain) receive Pt with Liver disease: If it can’t get broken down, may large amounts of circulating drug lead to toxic effect and overdose. C. Blood Brain Barrier – drugs must have high lipid solubility to achieve access to the brain (and spinal fluids) Drug Metabolism Terms Drug Metabolism Terms First Pass Metabolism Enzyme Induction drugs are absorbed into the portal circulation from the gut and ▪ metabolism can be quickened or slowed by more or less pass through the liver before distribution to the other organs or involvement of cytochrome P450 enzymes. (example tissues. grapefruit juice) Some drugs are metabolized significantly during this process ▪ The rate at which the enzyme metabolizes drugs can be known as “first pass metabolism” induced by exposure to certain drugs which can increase may reduce the concentration of the drug that reaches the the amount of enzyme present. target tissue ▪ This induction will decrease the duration of action of a Microsomal Metabolizing System drug and the concentration.  takes lipid soluble drugs and makes them water soluble for excretion by the kidney ****Many drug interactions are present because of the involvement of the cytochrome P450 system. Drug Excretion Blood Drug Levels Refers to the drug leaving the body, occurring by renal, GI, and Why perform A BLOOD DRUG LEVELS? respiratory pathways ✓ May be used to determine if drug is within therapeutic A. Renal Excretion – water soluble metabolites or water- range, where effectiveness is maintained, and toxicity is soluble drugs are filtered through the glomerulus of the absent. kidney ✓ Used mostly for drugs with a small therapeutic range or B. GI Excretion – Unabsorbed drug passes in feces drugs with high potential of toxicity. C. Respiratory Excretion – small role in most drug excretion, ✓ May also be used to determine compliance and/or significant role for inhaled gases. effectiveness of therapy How does kidney/renal disease or impairment affectExamples medications in the body? Antibiotics (systemic), specifically aminoglycosides Kidney damage: drugs could go through the kidney and is not Anticonvulsants properly absorbed for excreted properly or isn’t excreted at all. Anti-psychotics Anticoagulants, specifically Drug Indication – therapeutic purpose for administering a drug Affect of Patient Factors on Therapeutic Dosage Contraindication – situation or circumstance under which the WEIGHT: drug should be avoided dosage may have to be adjusted Why? larger weight = larger dose ✓ May often be patient specific disease or underlying condition (heart failure, liver, or kidney disease) AGE. ✓ May be due to taking another type of medication ✓ Consider infants and geriatric patients ✓ May be due to patient factors (pregnancy, allergies, age) ✓ Ability to metabolize drugs may vary ✓ Underdeveloped in infants and depressed in elderly Affect of Patient Factors on Therapeutic Dosage Emotional State: ✓ anxious/excited individual may require higher doses of SEX and % OF BODY FAT: anxiolytics or hypnotics, metabolism may be affected ✓ Effects distribution of drug Placebo Effect: ✓ Water soluble drugs stay in fluid compartment ✓ response to medication because patient believes that ✓ Fat soluble drugs accumulate in body fat therapy will be effective, influence of mindset on outcome ✓ Women higher % body fat, less body water Presence of Disease ✓ Different persons of same sex may have similar issues, ✓ Pre-existing disease stated may affect the ability of drug to lean vs. obese work or produce adverse events ✓ Liver or kidney disease causes accumulation of drug and Genetic Variation: an increase toxicity potential of the medication ✓ Inherit protein and enzyme patterns of parents Patient Compliance: ✓ Some enzymes may be missing ✓ Taking drug exactly as prescribed ✓ Dose according to convenience/compliance Drug Interactions Types of Drug Interactions Occur when the actions of one drug are 1. Incompatibility – physical alteration 4. Synergism – combined effect of two affected by the actions of another drug, when drugs are mixed drugs is greater than the sum of their resulting in: 2. Additive – combination of two drugs is individual effects ▪ Altered absorption, or equal to effect of each drug alone by 5. Antagonism – combined effect of two ▪ Altered distribution, or same mechanism of action drugs is less than the sum of their ▪ Altered metabolism, or 3. Summation – combination of two drugs individual effects ▪ Altered excretion. is equal to effect of each drug alone, 6. Potentiation – a drug which has no different MOA effect enhances the effect of a second drug Secondary Unintended Drug Effects Secondary Unintended Drug Effects 3. Adverse Effects – May be harmful if left untreated and Three “levels” or types: long-term exposure may affect organ function. May be 1. Side Effects – A predictable minor nuisance that may corrected by reducing dosage, if dose related, or by affect compliance with therapy. Generally, not harmful. discontinuing drug and commencing alternative therapy. 2. Toxic Effects – Harmful or life threatening due to poisoning, drug should be stopped and supportive care What is the difference between dose dependent and non-dose initiated. dependent effects? the key difference lies in how the effect of the drug relates to the dose administered. Dose-dependent effects show a clear relationship between increasing dose and increasing effect, while non-dose-dependent effects do not have such a predictable relationship and can be influenced by various factors, often leading to a plateau or increased side effects at higher doses. Understanding these differences is crucial for effective and safe medication management.  LECTURE 2 DEFINITION TO KNOW Terminology Review for Allergies, Antihistamines, and Antiallergens 1. Allergy: an immunologic reaction (hypersensitivity) to an antigen, may be allergic to environmental objects, drugs, animal dander, foods, etc., the reaction may present with sneezing, coughing, itching, headache, respiratory or cardiac failure. 2. Allergen: substance that precipitate allergic reactions, may include dust, mold, pollens 3. Antigen: antigen is derived from the allergen and stimulates an immune response in sensitized persons, repeated exposure to an antigen may result in allergic reactions (signals*) 4. Antibody: protein produced by immune system to attach to specific antigen upon exposure 5. Rhinitis: inflammation of the nasal mucosa 6. Erythema: redness of the skin caused by capillary dilation (i.e. flushing of ears/face) 7. Dermatitis: inflammation of the skin associated with burning, itching, edematous vesicles 8. Urticaria: hive-like rash 9. Anaphylaxis: a severe, whole-body allergic reaction. This reaction happens quickly after the exposure, is severe, and involves the whole body. 10. Histamine: substance that interacts with tissues to produce most of the symptoms of allergy, widely distributed in tissues like lung, skin, intestines, etc., located in mast cells and basophils (wbc) 11. H1-receptor: histamine receptor located in various tissues, specifically blood vessels, bronchioles, and intestinal smooth muscle 12. H2-receptor: histamine receptor located in stomach, heart, blood vessels, uterine tissues, controls secretion of gastric acid 13. Antihistamine: drug that blocks the action of histamine at the target organ 14. Antiallergic: drug that prevents mast cells from releasing histamine and other vasoactive substances 15. Xerostomia: dry mouth due to inhibition of salivary gland, typically side effect of medication Drug Interactions: 1st Generation Advantages of 2nd Generation Common Side Effects ▪ Older generation antihistamines have a ▪ More selective for peripheral More Common SE’s prominent sedating effect H1-receptors( example: ✓ Drowsiness and sedation ▪ Sedation is greatly increased when Reactine ) ✓ Dry mouth (xerostomia) antihistamines taken in combination Therefor a lot less ✓ Dry mucous membranes with: sedating 1st generation antihistamines have higher ✓ Hypnotics Therefor a lot less drying potential for all three ✓ Sedatives ▪ May be useful for patient’s Less Common SE’s (typically only seen in ✓ Anxiolytics refractory to older agents overdose) ✓ Alcohol ▪ Longer half-life, may be Hypotension (decrease in blood pressure ) ✓ Narcotic analgesics dosed once daily Urinary retention (holding in your bladder) ✓ Muscle relaxants Rapid heartbeat (tachycardia) : when your ✓ other CNS depressants blood pressure dops your body reacts to it right away and causes tachycardia Epigastric distress Antihistamines 1. Ethanolamines 3.Phenothiazines (Rx only) most sedating, highest anticholinergic effects high anticholinergic effects, moderate sedation Dimenhydrinate (Gravol) (OTC) Promethazine (1st generation) Diphenhydramine (Benadryl)(OTC) Prescribed when OTC options not effective for maintenance 2. Alkylamines 4.Other first generation highest potential for CNS stimulation, medium for  Hydroxyzine (Rx only) (1st generation) epigastric distress  Very sedating Chlorpheniramine (Chlor-Tripolon) (OTC)  Often prescribed for puritis/urticaria related reactions Antihistamines Groups 1-4 are “First Generation Antihistamines” (older) Second Generation (all OTC) Cetirizine: Reactine Fexofenadine: Allegra Loratadine: Claritin Desloratadine: Aerius Antiallergic Agents Cromolyn Sodium aka Sodium Cromoglycate (and Nedocromil, D/C’d) Dosage Forms and Strengths (use CPS to find) Nalcrom: treat allergic reaction to food Mechanism of Action: 100mg capsule Prevent release of histamine through degranulation of mast cell Opticrom: to relieve and treat eye Also called Mast Cell Stabilizers allergies Preventative strategy only Opth solution 2% Indications: Alocril: eye-related allergy symptoms, Prophylactic in: such as itchiness or watery eye chronic bronchial asthma (oral or inhaled) – adjunct tx Opth Solution 2% allergic rhinitis (nasal inhaler) Antihistamine blocks the histamine that is already food allergies (oral) released and is treatment and antiallergic prevents the allergic conjunctivitis (eye drops) release of histamine  Drug Brand Name Dosage Forms Strengths Prescription? dimenhydrinate Gravol Tablet, liquid, suppository, 25 mg, 50 mg No (OTC) chewable diphenhydramine Benadryl Tablet, liquid, cream, capsule, 25 mg, 50 mg No (OTC) injectable chlorpheniramine Chlor-Tripolon Tablet, liquid 4 mg, 12 mg (ER) No (OTC) promethazine Phenergan Tablet, injectable 25 mg, 50 mg yes hydroxyzine Atarax Tablet, syrup, injectable 10 mg, 25 mg, 50 mg yes fexofenadine Allegra Tablet 30 mg, 60 mg, 120 mg No (OTC) loratadine Claritin Tablet, liquid 5 mg, 10 mg No (OTC) cetirizine Reactine Tablet, liquid 5 mg, 10 mg, 20 mg No (OTC) desloratadine Aerius Tablet, liquid 5 mg No (OTC) Action of Histamine 1. Vascular Effects 2. Extravascular Smooth Muscle ▪ Contraction of smooth muscles (intestines or bronchioles) ▪ dilation of capillaries – transient (GI upset) ▪ Hypotension ( decrease in blood pressure) ▪ erythema in skin (flushing &redness) 3. Cardiac Effects ▪ leaky capillaries – fluid and proteins escape causing ▪ Rapid heartbeat irritation of nasal membranes or hives ▪ At high levels may cause arrhythmias Indications for Antihistamines Acute allergic reactions: hay fever, insect bites, pet dander, minor food/drug allergies rhinitis, dermatitis, itchy eyes, scratchy throat, urticaria, Dry nasal secretions (anticholinergic component) often in cough/cold products Sleep aids (due to sedative properties) Reduction of nausea and vomiting including Motion Sickness