Introduction to Pharmacology PDF

Introduction to Pharmacology Drugs and The Body A drug taken by mouth goes through three phases:  Pharmaceutic  Pharmacokinetic  Pharmacodynamic If the drug is given IM, IV, SC… there is no pharmaceutic phase! Drug Action   First phase of...

Introduction to Pharmacology Drugs and The Body A drug taken by mouth goes through three phases:  Pharmaceutic  Pharmacokinetic  Pharmacodynamic If the drug is given IM, IV, SC… there is no pharmaceutic phase! Drug Action   First phase of drug action  Drugs must be in a solution form to be absorbed by the GI tract.  Acidity, food, and tablet form may interfere with drug absorption.  Rate Limiting Pharmaceutic Phase The process of drug movement to achieve drug action. Absorption Distribution Metabolism Excretion/ elimination Pharmacokinetic Phase Absorption Movement of drug particles from GI tract to body fluids by: passive absorption active absorption pinocytosis.  Lipid or water  Route of soluble (blood- administration brain barrier)  First pass effect  Blood flow (hepatic first pass)  Temperature  Bioavailability  Food, hunger, fasting  Stress  Pain  Ph Factors affecting absorption  Percentage of administered drug that reaches the systemic circulation.  Rate at which the drug is absorbed affects the bioavailability.  Rapid absorption → ↑ bioavailability  Slow absorption → ↓ bioavailability  IV administration = 100 % bioavailability BIOAVAILABILITY  Process by which the drug becomes available to body fluids and tissues.  Protein- binding effect  Free drugs Distribution Protein binding percentage Plasma protein and albumin levels Liver disease Kidney disease Malnourished Elderly (hypoalbuminemia) Factors affecting Distribution  Liver is the primary site for metabolism Metabolism  Liver disease can cause decreased drug metabolism rates thus toxicity.  Half Life- t1/2: the time it takes for one-half of the drug concentration to be eliminated.  Main route through the kidneys  Drug accumulation can occur with kidney disease.  Creatinine Clearance- lab test to determine kidney function: nml= 85- 135ml/min.  Decreases with age thus may need to decrease doses for the elderly. Excretion/ elimination  Study of drug concentration and its effect on the body.  Dose-response and Maximal efficacy  Onset, Peak, Duration of action Pharmacodynamic phase  Drugs act through receptors by binding to the receptor to produce a response or to block a response.  Agonists (produce a response)  Antagonists (block or prevent a response)  Nonspecific and nonselective drugs Receptor Theory Receptor Theory  Adrenergic  Adrenergic agonists blockers ◦ Dilate pupil ◦ Constrict pupil ◦ Dilate lungs ◦ Constrict ◦ Increased HR bronchioles ◦ Constrict blood ◦ Decreased HR vessel ◦ Vasodilation ◦ Relax bladder, ◦ Contracts uterus GI, uterus Agonists vs. Antagonists- Adrenergic Drugs (Covered wk 11)  Cholinergic  Cholinergic agonists antagonists ◦ Constrict pupil ◦ Dilated pupils ◦ Constrict bronchioles ◦ Dilated bronchioles ◦ Decreased HR ◦ Increased HR ◦ Vasodilation ◦ Urinary retention ◦ Contracts bladder ◦ Constipation ◦ Increased peristalsis ◦ Dry mouth and ◦ Increased salivating, mucous membranes sweating, tears Agonists versus Antagonists- Anticholinergic Drugs (Week 11) Nonspecific drug effect Nonselective drug effect  Stimulation or depression  Replacement  Inhibition or killing of organisms  Irritation Categories of drug action  Peak  Pharmacogenetics  Trough  Tachyphylaxis  Loading Dose  Placeboeffect  Side effects  Therapeutic  Adverse window (range) reactions  Therapeutic index  Toxic effects/ toxicity Additional terminology Summary Practice Question #1 Mr. Jones has liver and kidney disease. He is given a medication with a half-life of 30 hours. You expect the duration of action of this medication to: A. increase. B. decrease. C. remain unchanged. D. dissipate. In the older adult and those with renal dysfunction, the creatinine clearance is usually: A. substantially increased. B. slightly increased. C. decreased. D. in the normal range. Practice Question #2 Toxic Effects of Drugs  Drug interaction  Drug-food  Adverse drug interactions effect  Drug-drug  Drug interactions incompatibility  Drug-laboratory  Pharmacokinetic interactions interactions  Drug induced  Additive effect photosensitivity  Synergistic effect  Drug abuse (potentiation) *** Always must look up drugs in a current drug guide before  Antagonistic effect administering DRUG INTERACTIONS  Dermatological Reactions  Superinfections  Blood Dyscrasia  Toxicity  Alterations in glucose metabolism  Electrolyte imbalances  Sensory effects  Neurological Effects  Teratogenicity Drug induced Tissue and Organ Damage The Nursing Process and Patient Safety C. 4 The Nursing Process (ADPIE)  Assessment Subjective data  Current health history  Client symptoms  Current medications  Past health history  Client’s environment Objective data Do not forget about cultural considerations! Nursing Process  Knowledge deficit about drug action, administration, side effects r/t language difficulties  Ineffective health maintenance r/t not having recommended preventive care  Ineffective protection r/t effects of anticoagulants on clotting factors  Ineffective therapeutic regimen management  Noncompliance r/t forgetfulness  Risk for injury r/t side effects of drug therapy Nursing Diagnosis  Characterized by goal-setting ◦ Example: Mrs. Smith will independently administer prescribed dose of albuterol by the end of the first session of instruction  Characteristics of a goal ◦ Client centered; clearly states the expected change ◦ Realistic and measurable ◦ Realistic deadlines Planning  Nursing actions necessary to accomplish the goals  Client teaching ◦ General ◦ Self-administration ◦ Diet ◦ Side effects ◦ Cultural Considerations Implementation  The effectiveness of health teaching about drug therapy  Goal attainment  If goals not met… nurse needs to determine the reasons and revise the plan. Evaluation Which of the following is a correctly written goal? A. EZ will administer the prescribed dose. B. EZ will learn to administer insulin. C. EZ will know how to take insulin correctly. D. EZ will independently administer prescribed dose of insulin at end of 1 hour of instruction. Practice Question #1  Right client  Right  Right drug documentation  Right dose  Right  Right time assessment  Right route  Right to education  Right evaluation  Right to refuse “five plus five rights”  Absorption  Time of  Distribution administration  Metabolism  Emotional factors  Excretion  Preexisting  Age disease state  Body weight  Drug history  Toxicity  Tolerance  Pharmacogenetics  Cumulative effect  Route of  Drug–drug administration interaction  Drug–food interaction Factors that modify drug response  Tablets and  Instillations capsules  Inhalations  Liquids  Nasogastric and  Transdermal gastrostomy  Topical tubes  Suppositories  Parenteral Forms and routes  Use TWO identifiers  Reconciling  Timely Reporting of Medications across critical tests and the continuum critical results  Providing patient  Safe Labeling with reconciled  Anticoagulation medication list Safety  Patient Knowledge  Hand Hygiene  Preventing Infection National Patient Safety Goals  QSEN (Quality and Safety in the Education of Nurses)  Disposal of medications  Counterfeit Drugs  Pill splitting  Internet consumerism  Do not crush  High Alert Medications  Look Alike-Sound Alike  Pregnancy Categories  Prevention of Medication Errors Culture of Safety Challenges to effective drug therapy C. 6  Cultural Considerations  Over the counter Medications  Geriatric Considerations Challenges to effective Drug Therapy   Ethnopharmacology  Pharmacogenetics  Efficacy  Adherence  High-risk behaviors Transcultural Considerations  Caution required OTC cold and cough remedies OTC sleep aids OTC weight-control drugs Polypharmacy OTC DRUGS Cautions with Use of OTC Medications  Delay in professional diagnosis and treatment  Symptoms may be masked  Read labels  Consult health care provider before use  Inactive ingredients may cause adverse reactions  Potential for overdose  Intentions of Rx and OTC medicines Aging population Physiologic changes Polypharmacy Pharmacokinetics Pharmacodynamics Adherence/ Nonadherence Geriatric Pharmacology  Too many meds at many different times  Knowledge Deficit  Memory Deficit  Impaired Mobility  Sensory Deficits  Cost  Side effects or adverse reactions Barriers to effective medication use in the older adult Cost of health care Off Label Uses Environment consideration Emergency Preparedness Alternative therapies Drug Abuse Media Influence Internet Consumerism Additional Challenges Health Teaching: Special Considerations Senses as sharp as possible: clean eyeglasses; working hearing aids in Provide place, etc. Communicate Speak in tones client can hear; face client when speaking Respect Treat client with respect; expect that he/she can learn Engage Use large print, bright colors in teaching aids Health Teaching: Special Considerations (cont’d)  Review all medications at each visit  Encourage simple dosing schedule  With onset of confusion or disorientation, suspect recently prescribed medication(s)  Encourage client to report if the new drug is not improving the condition for which it was prescribed Adverse reactions and drug interactions occur frequently in the older adult due to which of the following: SELECT ALL THAT APPLY A. consumption of numerous drugs due to multiple chronic illnesses. B. drugs ordered by several health care providers. C. increased incidence of allergic responses. D. self-medication with OTC preparations. Practice Question CENTRAL NERVOUS SYSTEM DEPRESSANTS: SEDATIVES- HYPNOTICS Review of Sleep/ Disorders  NREM  REM  Insomnia Treatment  Nonpharmacological - Arise at the same time - Avoid daytime naps - Avoid caffeine 24h STEROID CONSIDERATIONS  Do not stop abruptly; important to be tapered; gradually weaned off  May elevate blood sugars (hyperglycemia)  Causes immunosuppression  Lab Interactions: Elevated blood glucose, elevated WBC’s DISEASE-MODIFYING ANTIRHEUMATIC DRUGS (DMARDS)  Uses: As anti-inflammatory for Rheumatoid Arthritis (RA)  Types: Immunosuppressive, Immunomodulators, Antimalarials DMARD: IMMUNOSUPPRESSIVE  Action: primarily used to suppress cancer growth and proliferation, but might also be used to suppress the inflammatory process of RA  Imuran, Cytoxan, methotrexate DMARD: IMMUNOMODULATORS  Disrupt the inflammatory process and delay disease progression  Predispose patient to severe infection  TNF Blockers  Bind to TNF and block it from attaching to TNF receptors on synovial cell surfaces  Etanercept (Enbrel), influximab (Remicade), (Humira)  Interleukin (IL-1) receptor antagonists  IL-1 is a proinflammatory cytokine that contributes to synovial inflammation and joint destruction  Anakinra (Kineret) ANTIMALARIALS  Action:anti-inflammatory, analgesic for RA (Rheumatoid Arthritis)  Response: May take up to 4-12 weeks May be used in combination with NSAIDS GOUT  Inflammatory process  Attacks joints, tendons, other tissues (gouty arthritis)  Cause: uric acid metabolism disorder and defect in purine metabolism that leads to hyperuricemia  Complications of hyperuricemia: pain, urinary calculi, gouty nephropathy ANTI-INFLAMMATORY GOUT DRUG: COLCHICINE  Action: Inhibits migration of leukocytes  Side effects: N, V, D (75% taking high doses)  Contraindications: Severe renal, GI problems  Nursing Implications:  Avoid foods rich in purines (wine, alcohol, organ meats, sardines, salmon, gravy)  Increase fluid intake  Take acetaminophen for pain; Not ASA URIC ACID INHIBITOR – ALLOPURINOL (ZYLOPRIM)  Action: lowers serum uric acid  Frequently used prophylactically to prevent gout; Not used for acute gout  Interactions:  Nursing Implications:  Increase water intake  Avoid alcohol, caffeine, & thiazide diuretics  Yearly eye exam URICOSURICS  Action: Increase rate of uric acid excretion by inhibiting its reabsorption  Use: chronic gout  Nursing Implications:  Increase water intake  Avoid ASA (may cause uric acid retention)  Take with food OTHER DRUGS  NSAID: Indomethacin (Indocin) for short-term management of acute gout  Immunosupressants  Uses: refractory RA, cancer  Names: azathioprine (Imuran), cyclophospanide (Cytoxan), methotrexate (Mexate)  Etanercept (Enbrel) Approved April 2004 for advanced rheumatoid arthritis  Costs up to $12,000/year treatment Analgesics ⚫ Prescribed for the relief of pain ⚫ Nonnarcotic and narcotic ⚫ Prescribed based on type of pain Pathophysiology 1. Tissue damage occurs 2. Release of chemical mediators (bradykinin, serotonin, prostaglandins) 3. Affect the exposed nerve endings of the nociceptors (pain receptors) 4. Nociceptors found in all body tissues… body organs have few but are more sensitive. Types of pain ⚫ Acute- mild, moderate, severe (non-narcotic and narcotic) ⚫ Cancer- pressure on organs/ nerves, mets to bone (narcotic) ⚫ Chronic- > 6 months, difficult to treat/ control (non-narcotic preferred, narcotic if meets criteria) ⚫ Somatic- skeletal muscle, ligaments, joints (NSAIDS) ⚫ Superficial- mild, skin, mucous membranes ⚫ Vascular- h/a, migraines (non-narcotic, others) ⚫ Visceral- smooth muscle and organs (narcotics) Nonnarcotic ⚫ Salicylates and NSAIDS ⚫ Acetaminophen ⚫ Antipyretics ⚫ Not addictive ⚫ Less expensive ⚫ OTC ⚫ Mild to moderate pain Acetaminophen ⚫ Uses: analgesic, antipyretic ⚫ Point of interest: Does not cause REYE syndrome, gastric irritation, or blood thinning. Does not have anti-inflammatory properties ⚫ Overdose is life threatening. Hepatotoxicity- early symptoms = n/v/d, abdominal pain Narcotic Analgesics ⚫ Narcotic agonists, act on CNS, suppress pain impulses. ⚫ Also suppress coughing and respirations ⚫ Uses- Moderate/ severe pain, antitussive, antidiarrheal effects ⚫ Common side effects- n/v, constipation, decrease BP, urinary retention (with older adults), decreased coughing, tachycardia, mental clouding, drowsiness ⚫ Adverse effects- orthostatic hypotension, respiratory depression. Tolerance, dependence, abstinence syndrome. ⚫ Contraindications- head injuries, respiratory disorders, shock, hypotension. Morphine ⚫ Opiod ⚫ AMI, CA, acute pain, severe pain ⚫ Antidote is NARCAN (narcotic antagonist) ⚫ Frequently used for PCA’s ⚫ Sustained release, IV, PO, SC, IM, liquid preparations. ⚫ IV Push over 4-5 minutes! Hydromorphone ⚫ Six times more potent than Morphine ⚫ Shorter duration of action ⚫ Faster onset ⚫ IV Push 2-5 minutes ⚫ Must dilute with Normal saline. Others ⚫ Combination drugs- (hydrocodone/acetaminophen) Vicoden, (codeine/ acetaminophen)T#3 ⚫ Transdermal opiod analgesics- ATC coverage, fentanyl ⚫ Narcotic antagonists- Nalaxone ⚫ Methadone treatment program ⚫ Patient Controlled Analgesia Adjuvant Therapy ⚫ Anticonvulsants (~gaba) ⚫ Muscle spasm (baclofen, cyclobenzaprine) ⚫ Antidepressants ⚫ Corticosteroids (~one) ⚫ Antidysrhythmics ⚫ Local anesthetics (~caines)  View Image Muscle relaxants ⚫ Cyclobenzaprine, baclofen ⚫ Decrease spasticity and pain related to muscular hyperactivity. ⚫ Dizzy, drowsy, do not take with other CNS depressants, alcohol ⚫ Contraindicated if MG or glaucoma ⚫ Hepatotoxic- monitor liver enzymes. ⚫ Taper dose, no longer than 3 weeks. WHO- Pain relief ladder