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Class 1
HCC 2008 Pharmacology
Question | Answer |
---|---|
Pharmacology | The study of chemicals (drugs) that alter functions of living organisms |
Pharmacotherapy | (drug therapy) The use of drugs to prevent, diagnose, or treat signs, symptoms and disease processes. |
Pharmacokinetics | drug movement through the body. What the body does to the drug. Includes: Absorption, distribution, metabolism, excretion |
Pharmacodynamics | Drug actions on target cells and the resulting alterations in cellular biochemical reactions and functions. What the drug does to the body. |
Drugs | chemical substances that affect cellular function |
Medications | drugs given for therapeutic purposes |
Local effect | works on a specific area of body |
Systemic efect | works on various body tissues throughout the body (most meds) |
Immediate or Long-term effects | Immediate- like an infectionLong-term- parkinsons disease |
Sources of drugs | Plants (morphine), Minerals (iron), Animals (insulin), Synthetic (less allergies, biotechnology (DNA&RNA manipulation) |
Names of drugs in 3 categories | Chemical name (Salicylic Acid), generic name (Aspirin), trade/brand name (Bayer) |
Classification | Major: according to body system, which one it effects(cardiovascular)Minor: indicates use or purpose (antianginal) |
Prototype | drugs that represent groups of drugs (first drug-standard for comparison) ex. morphine for opioids |
Role of the FDA? | *regulates and monitors drug approval process*enforces drug dispensing laws (can change Rx to OTC) |
USP | US Pharmacopeia- provides drug standards for quality strength and purity. |
Phase 1 Drug approval process | given to healthy volunteers |
Phase 2 drug approval process | given to persons with disease or symptoms |
Phase 3 drug approval process | given to larger group of people with disease (blind & DB studies occur w/ use of placebo |
Phase 4 drug approval process | drug is marketed for general use (adverse effects, MEDWATCH, drug could still be removed) |
Controlled substances | Narcotics, depressants, stimulants, hallucinogens. High potential for abuse/ dependency. physical(withdrawal) or psychological(addiction) |
Controlled substance act | regulates the manufacturing and distribution of these drugs |
DEA | Drug Enforcement Administration: enforces controlled substance act |
Schedules 1-5 | the lower the #, the higher potential for abuse. These differ in dispensing regulations. EX:schedule II-72 hr stop date-no refills |
nursing responsibilities | Keep drugs locked, sign-out procedure for narcotics, record drug removed, record amount used and amount left |
wasting narcotics must be: | witnessed and co-signed by another nurse |
Drug Action on the Cell | drugs stimulate or inhibit normal cellular function. Drugs can't add functions. Drugs must reach adequate concentration in blood in order to act on cells. Drugs must be eliminated from body. |
Absorption | time drug enters the body to time drug enters the bloodstream to be circulated. |
Factors affecting absorption: | dosage:too small, too large, correct dose, loading dose, form of dose, route,food. |
Loading dose | 1st dose for maximum effect |
Forms of dosage | Liquid (absorb faster then tablets), Tablets, gases |
Kinds of tablets | Enteric coated- broken down in intestine, can't crush, highly irritating.EXtended release- breakdown in stomach, CR,SR,LAScored- line through it, can break. |
Routes | Enteral: GI tract (oral, NGT, GT)Parenteral: Non-GI tract (injection, IV, topical) Absorbed faster in blood |
Food and Absorption | Food SLOWS down absorption and may decrease amount of drug absorbed. Some drugs good, some bad |
Distribution | drugs transported from bloodstream to site of action. Determined by bloodflow. Decrease in CO or circulation will reduce it. |
Protein binding | Drug binds to albumin. When bound to protein, drug is inactive. Only the free/unbound portion of drug acts on cells. |
What does 30% bound to plasma proteins mean? | 70% of the drug is active, 30% inactive. |
What does protein binding allow? | It allows part of the drug to be stored and released as needed. |
What is normal range for serum albumin level (primary protein)? | 3.5 to 5.0g/dl |
What happens when the albumin level is too low? | *higher amount of free drug*greater potential for toxic & adverse effects |
Ability for drug to cross certain membranes? | blood-brain barrier: protects CNS, impermeable to most drugs. Drugs must be lipid soluable for CNS distribution.Placenta: most drugs can cross throughBreast milk: many drugs |
Metabolism | The breakdown to inactivate the drug |
Main organ of metabolism? | Liver |
How does Metabolism work? | It converts fat-soluable drugs into water-soluable metabolites. Enzymes also inactivate drug. |
WHy are oral doses generally larger than parenteral? | It breaks down and absorbs a lot into the GI tract before reaching body. |
First-pass effect | Oral drugs travel to portal vein and liver before entering general circulation |
What happens with impaired liver function? | Delayed metabolism, drug accumulation, adverse reactions/toxicity, dose reduced. Larger dose should be used. |
Excretion | Elimination from body. Primarily kidneys. |
What happens with impaired kidneys? | Impaired kidneys-impairs excretion- drug accumulation-ADR/toxicity. Reduce the dose, monitor kidneys (creatinine levels and I&O) |
What is purpose of serum drug levels? | Measures the amount of drug in the blood. |
Toxic concentration | an excessive level of drug in blood where toxicity occurs |
Therapeutic range | drug concentration that produces the desired effect |
Half-life of a drug | The time required for the serum concentration of a drug to decrease by 50%. |
Importance of half-life | So you don't overdose patient, and it determines the dose scheduling (drugs w/short life require frequent dosages) |
How do drugs perform effects on the body? | CHemically by binding with receptors at the cellular level. Drug fits into receptor sites like key and lock. Can inhibit of stimulate cell function. |
Receptors | proteins on the surface of cell membranes or in the cell |
Intensity of drug on the cells depends on what? | *How well it fits into the receptor sites*How many receptor sites are occupied |
How do drugs cause depolarization of cells? | By changing the permeability of the cell membrane to one or more ions causing depolarization(excitation) of cell: opens or closes ion channels ex. Na+ Cl+ |
What is the action of drugs on neurotransmitters? | they can modify the release, synthesis, or inactivation of neurotransmitters (regulate physiologic processes) ex.norepinephrine, seratonin, acetylcholine |
Drug-drug interactions | drug action may be increased or decreased when 2nd drug taken. Caused by altered drug metabolism or competition for binding sites. |
Additive effect | occurs when 2 drugs are taken with similar action causing an increase in effects. ex. morphine w/alcohol=decreased RR & increased sedation |
Antagonistic effect | drug effects are decreased. ex. tetracycline and antacid=decreased absorption of tetracycline |
Synergistic effect | 2 drugs with different actions produce greater effect than either given alone. ex.codeine and tylenol=greater pain relief |
Interference | when one drug interferes with the metabolism or elimination of a 2nd drug causing an increased effect of the 2nd drug. ex. tagamet and theophylline=decreased theophylline metabolism |
Agonist | a complete attachment and cellular response occur. Similar to natural processes of neurotransmitters or hormones (morphine stimulates supression of pain signals) |
Partial agonist | cause a small response in cell and block other responses |
Antidote | a drug given to reduce the toxic effects of another drug. ex. Narcan to relieve effects of morphine |
Antagonist | drugs that inhibit cell functions by attaching and blocking receptor sites to natural body substances or other drugs. ex. Narcan- wakes you up |
Food can alter:tetracycline,warfarin/coumadin, calcium channel blockers in what ways | *Dairy products reduce absorption of tetracycline.*Foods high in vitamin K can interact w/ anticoagulants*Grapefruit juice |
Unit dose | pre-measured, individual packaged dose |
Variables that effect druge action | Age- young &old sensitiveweight- dosagegenetics- enzymes differentdisease processpregnancy/breastfeeding |
Hepatotoxity | liver damage (adverse effect) |
Nephrotoxicity | renal damage (adverse effect) |
Tolerance | larger doses needed to produce same effect (withdrawal symptoms can occur but doesn't mean addicted) |
idiosyncratic | first dose- unexpected reaction |
allergic | antigen/antibody reaction |
cumulative effect | 1st dose not fully metabolized before another dose is given. can cause permanent or temporary damage to body tissues. Promote elimination, ABCs, IV, etc. |
Controversial | Giving Ipecac, gastric lavage, charcoal |
Maintenance therapy | drug taken on regular schedule to maintain steady drug level. ex. antihypertensive medication |
Prophylactic therapy | drug given to prevent illness from occurring ex. low dose heparin to prevent clots after surgery |
therapeutic index | ratio of drugs lethal dose to its therapeutic dose. Lower the therapeautic index, the more narrow range. |
Pregnancy category | Pc-A- no riskPC-X- contradicted (teratogenic effects)PC B ex.morphine is safe to give |
Narcotic analgesics | Action: relieve pain, inhibits the transmission of pain signals from peripheral tissues to the brain. It prevents of relieves acute/chronic pain |