Lesson 1 – Intro to Pharmacology PDF

LESSON 1 – INTRO TO PHARMACOLOGY Four Basic Terms in Pharmacology Term De nition Drug Any chemical that can a ect living processes Pharmacology The study of chemicals and their interactions with living...

LESSON 1 – INTRO TO PHARMACOLOGY Four Basic Terms in Pharmacology Term De nition Drug Any chemical that can a ect living processes Pharmacology The study of chemicals and their interactions with living systems Clinical Pharmacology The study of drugs in humans Therapeutics The use of drugs to diagnose, prevent/treat disease or to prevent disease; in other words, it is the medicinal use of drugs Characteristics of an Ideal Drug In theory, these would be the big three characteristics of a perfect drug: – E ective Most important property a drug can have – Safe Aatsafe drug is one that cannot high doses very long time produce harmful e ects – even – Selective Elicits only the response for which it is given TAKE NOTE: there is NO perfect drug Additional Characteristics of Ideal Drugs Reversible Action Predictability Ease of Administration Freedom from Drug Interactions Low Cost Chemical Stability Because No Drug is Ideal…..our therapeutic objective should to provide maximum bene t with minimal harm; in other words, We should aim maximize our bene t-to-harm ratio Factors that Determine Drug Response Intensity Think About It… 1. Which of the previously stated routes of administration do you think is the most commonly prescribed route?
2. What are other routes of administration can you think of that wasn’t stated in the previous slide? Drug – Our body has many di erent Receptor receptors with many di erent functions (ex: beta-1 receptor in Interactions the heart regulates heart rate) Drugs bind to these receptors to either activate or inhibit its function Note: chemicals bind selectively to speci c receptors (refer to gif)  Agonists vs Partial Agonists vs Antagonists Agonists receptors are molecules that mimic endogenous compounds which activate – Ex: dobutamine mimics norepinephrine which activates beta-1 receptors in the heart Antagonists are molecules that produce their e ects by preventing receptor activation. the lock) (Think of how blocking the key hole prevents the key from unlocking – Ex: metoprolol blocks the binding of norepinephrine, thus, blocking the receptors action Partial Agonists are like agonists but does not produce the maximal e ect that a regular agonist can – Take note: in the presence of an agonist, partial agonists competes with receptors, thus, becoming an antagonist Drug Interactions Drug-to-drug Interaction – Types Additive (1+1 = 2) – Their combined e ect is equal to the sum of their individual e ects – Example: Combining two non-opioid analgesics such as paracetamol + ibuprofen Potentiation (1+0 = 2) – One drug has a di erent action than the other drug but when combined together they enhance the e ect of each other – Example: Amoxicillin + Clavulanic Acid (aka Co-amoxiclav) Synergistic (1+1 > 2) – Their combined e ect is greater when given together – Example: Sulfamethoxazole + Trimethoprim (Co-trimoxazole) Antagonistic (1+1 = 0) – These drugs cancel each other out – Example: Morphine + Naloxone Drug Interactions Drug-to-Drug Interactions – CYP450 System Certain drugs may cause an increase or decrease of levels of certain drugs Remember! – CYP450 Enzyme inducers = decreased drug levels – CYP450 Enzyme inhibitors = increased drug levels – CYP450 Inducers (CRAP GPS) Carbamazepine, Rifampicin, Alcohol, Phenytoin, Griseofulvin, Phenobarbital, Sulfonylureas – CYP450 Inhibitors (SICKFACES.COM) Sodium Valproate (aka Valproic Acid), Isoniazid, Cimetidine, Ketoconazole, Fluconazole, Alcoholism & Grapefruit Juice, Chloramphenicol, Erythromycin, Sulfonamides, Cipro oxacin, Omeprazole, Metronidazole – For a more complete list, please refer to page 57 of our textbook Before we proceed…. …let’s test your understanding! If drug X is taken with an enzyme inducer like Phenytoin, levels of drug X within the body will most likely: (a) increase, (b) decrease or (c) have no e ect? If drug Y is taken with an enzyme inhibitor like Sodium Valproate, levels of drug Y within the body will most likely: (a) increase, (b) decrease or (c) have no e ect? More Drug Interactions! Drug-to-Food Interactions – Certain foods can cause interactions with di erent medications: Green, leafy vegetables – May interact with anticoagulant e ects of aspirin and warfarin Grapefruit Juice – Please refer to next slide for a complete table of interactions Dairy Products such as milk, yogurt and cheese – May decrease absorption of certain antibiotics – Cheese may cause hypertensive crisis when taken together with antidepressants under the family of Monoamine Oxidase Isocarboxazid, Phenelzine and Selegiline) Inhibitors (Ex: Tranylcypromine, Alcohol – A ects excretion of insulin and other oral antidiabetic agents; may cause hypoglycemia – Interacts with diphenhydramine to cause severe drowsiness The Modi ed Nursing Process in Drug Therapy Drug Nomenclature Drugs have three (3) di erent names 1. Chemical Name Uses nomenclature based on the chemical structure of the drug – Ex: para-acetyl-amino phenol 2. Generic Name Also known as the non-proprietary name – Ex: paracetamol 3. Brand Name Also known as brand name or trade name – Ex: Biogesic®, Tylenol®, etc Remembering Di erent Drug Classes Generic vs Branded Drugs Let’s end the generic vs branded debate once and for all Please refer to this screenshot from the textbook Lehne’s Pharmacology for Nursing Care (2018): Term De nition Adverse Drug Reactions Example Side E ect Nearly unavoidable secondary drug e ect Drowsiness produced by traditional antihistamines produced at therapeutic doses Toxicity The degree of detrimental physiologic e ects Severe hypoglycemia from insulin overdose by excessive drug dosing Allergic Response An immune reaction that is independent of Anaphylaxis from Penicillin administration drug doses Idiosyncratic An uncommon drug response from a genetic Red blood cell hemolysis from aspirin administration E ects disposition in patients with G6PD de ciency Paradoxical E ect A response that is the opposite of the Drowsiness from ca eine administration intended drug response Iatrogenic A disease that occurs as a result of medical Parkinson-like symptoms from taking anti-psychotic Disease care or treatment drugs Carcinogenic Ability of certain medications and Ironically, anticancer drugs have the greatest E ect environmental chemicals to cause cancers capacity to cause cancer Teratogenic A drug-induced birth defect Renal dysgenesis caused by giving captopril during E ect pregnancy (See following slides for more info on pregnancy and lactation) Medication Errors Estimated to injured over 1.3 million patients in the United States, yearly Caused over 400,000 patient deaths in 2016 (According to the FDA) One way of preventing medication errors is to simply know the causes – Refer to the following slides for a list of medication errors Medication Errors Causes – Human Factors Human Factor Example Performance De cit Improper administration technique that resulted in SQ administration instead of IV Knowledge De cit Administering two drugs that interact with each other simultaneously Dosage Giving 500 ml of drug X instead of 650 ml due to miscalculation Miscalculation leading to underdosing Drug Preparation Failure to adequately dilute intravenous medication leading to Error phlebitis Transcription Error Accidentally reading ”300 ml” as ”800ml” due to illegible writing Lifestyle Factors Decreased concentration on tasks resulting in patient overdose (Stress, Lack of Sleep, Fatigue) Medication Causes – Communication Mistakes Communication Example Mistake Written Illegible handwriting contributed to misinterpretation of a drug order, so the miscommunication patient received the wrong drug. Oral A verbal order for cefuroxime, a second- generation cephalosporin, was transcribed as miscommunication cefotaxime, a third-generation cephalosporin. Medication Errors Causes – Name Confusion Communication Example Mistake Brand Name Celebrex, an analgesic to manage pain, was confused with Celexa, a drug used to manage Confusion depression. Generic Name Chlorphenamine, an antihistamine present in nasal decongestant medications, is mistakenly Confusion given to a pediatric patient from Chloramphenicol, an antibiotic that may cause gray baby syndrome Medical Abbreviations More Abbreviations Conversions Factors Sample Problem 1 Physician’s Orders: Give rosuvastatin 20mg bid PO ac Available Dosages: Rosuvastatin 10mg Question: How many tablets will you administer in 12 hours? Sample Problem 2 Physician’s Orders: Give metformin 500 mg tid PO ac Available Dosages: Metformin 500 mg Question: How many tablets will you administer in 3 days? Sample Problem 3 Physician’s Orders: Infuse 1.5L of D5NSS over 12 hours. Drop factor is 20 drops per ml. Question: Calculate the drops per minute needed. Sample Problem 4 Patient Information: 7 years old, male, 40kg Physician’s Orders: Infuse 0.5L of D5IMB over 12 hours. Question: Calculate the drops per minute needed. Sample Problem 5 Physician’s Orders: Give 20 mg per kg of amoxicillin suspension PO tid for 7 days. The baby weighs 7 kg. Available Dose: 125 mg per 5 ml Question 1: How many ml should we give the baby for EACH DOSE? Question 2: If the bottle is only 60ml, how many bottles do we need to complete the antibiotic therapy?  Sample Problem 6 Physician’s Orders: Give paracetamol syrup 15 mg/kg PO q4h prn for fever Patient’s Weight: 25kg Available Dose: Refer to image → Question: How many ml of Tempra® syrup will you administer per dose? Sample Problem 7 Physician’s Orders: Give ceftriaxone 1g IV q12h Available Dose: Ceftriaxone 500mg/ ampoule Question: How many total ampoules will you give to the patient within a 24-hour period?  Things to Remember when Administering Drugs pt. 1 Administer READ KNOW Do NOT leave Check Only administer medications READ KNOW your meds Do NOT leave Check medication YOU have medication medications at compatibility if prepared label carefully Why is this patient receiving this med? the bedside administering IV What changes should I observe? meds What are the nursing actions speci c to this med? Things to Remember when Administering Drugs pt. 2 Medications prepared for one route may di er in concentration for a di erent route Use AT LEAST TWO identi ers to check determine the correct patient before administering any type of medication Have another nurse check medication calculations Do NOT inject more than 3 mL at one time For IM injections Use the smallest gauge necessary  HOW DO WE APPLY THIS KNOWLEDGE, THEN? Application of Pharmacology in Patient Care Pre-administration assessment – Three (3) Basic Goals Include: 1. Collecting baseline data to evaluate therapeutic and adverse responses – Ex: Baseline blood pressure before administration of BP meds 2. Identify high-risk patients – Ex: Identifying patients with penicillin allergies before administering Amoxicillin 3. Assessment of patient’s capacity for self-care – 1 & 2 cannot be achieved without understanding pharmacology Application of Pharmacology in Patient Care Dosage and Administration – Guidelines to ensure correct administration: Read medication order carefully – Verify with prescriber if unclear Verify identity of the patient Read medication label – Verify identity of drug, amount of drug and suitability for administration Verify dosage calculations Implement special handling requirements Don’t its useadminister any drug if you don’t understand the reason for Application of Pharmacology in Patient Care Promotion of Therapeutic E ects – Drug therapy can often be enhanced by non- pharmacological measures like: 1. Enhancing drug therapy of asthma through breathing exercises and emotion support 2. Enhancing drug therapy of arthritis through exercise, physical therapy and rest 3. Enhancing drug therapy of hypertension through weight reduction and smoking cessation Application of Pharmacology in Patient Care Minimizing Adverse E ects – To help reduce adverse e ects, nurse must know the following: Major adverse e ects of the drug When these reactions are likely to occur Early signs that an adverse reaction is developing Interventions that can minimize discomfort or harm – Ex: administration of glucose to a patient with insulin- induced hypoglycemia Application of Pharmacology in Patient Care Minimizing Adverse Interactions – As a nurse, you can help reduce the incidence and intensity ways by: of adverse interaction in several Taking a thorough drug history Advising the patient to avoid OTC meds that can interact with prescribed medication Monitor for adverse interactions that are known to occur Be alert to the possibility of unknown interactions Application of Pharmacology in Patient Care Making PRN decisions – PRN = pro re nata meaning “as needed” Ask yourself: “does the patient need this right now?” – More pharmacology knowledge = better PRN decisions Application of Pharmacology in Patient Care Evaluating Response to Medication – Evaluation is the process that tells us whether a drug is producing a bene t or is causing harm – In order to make proper evaluations, the nurse must understand the reason for its use Application of Pharmacology in Patient Care Managing Toxicity – To minimize harm, a nurse must know the early signs of drug toxicity and the procedure for toxicity management Announcement! We will be having a quiz next meeting before class starts Any questions? → See you next week!