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Unit 5 Basic Pharmacology and Contrast Media Chapters 20 & 21 Pharmacology Chapter 20 Introduction • Pharmacology – Study of drug actions on & drug interactions within living organisms • Drugs – Chemical substances that are not required for normal sustenance & that produce a biological effect in an organism – All drugs, if misused, are poisons Scope of Practice • Radiographer’s ability to administer drugs & perform venipuncture vary from state to state • Expected to know safe dosage, safe route of administration, limitations of drug, side effects, potential adverse & toxic reactions, indications & contraindications for its use Scope of Practice • If drug administration errors occur because of lack of knowledge, the person who administers the drug is legally liable • Errors associated with drug administration are the most common legal problem for RTs • Drug administration must be charted! – Name and dose of drug – Route of administration (& site) – Date and time Drug Standards • Food & Drug Administration (FDA) – Enforces strict standards for control of drug safety – New drugs must be tested on animals and/or humans – Properties regulated • Purity, bioavailability, potency, efficacy, safety & toxicity Drug Nomenclature • A classified system of names – By name – By action – By method of legal purchase • Drugs have 3 different names – Chemical name – Generic name – Trade name Classification by Name • Chemical name identifies the chemical structure of the drug – Ex: 7-chloro-1,3dihydro-1-methyl-5-phenyl-2H-1,4benzodiazepin-1-one • Generic name (aka “nonproprietary name) is simpler, easier to pronounce, not capitalized – Ex: diazepam • Brand name is specific to the company (trademark); always capitalized – Valium Classification by Action • Drugs with similar chemical actions are grouped into categories called drug families – Ex: analgesics, antihypertensives, antiinflammatories Legal Classification • Prescription vs. Nonprescription • Prescription drugs require an order by a physician. – Dispensed only by a pharmacist • Nonprescription drugs = over-the-counter (OTC) drugs – Also dietary supplements Drug Control • Over-the-counter drugs (OTC) – Drugs that are considered safe for selfadministration – May be prescribed drugs sold in lesser potency – Must be deemed safe by FDA • Dietary supplements not controlled by the FDA! – Important to note OTC drugs in patient history • Some interact with prescription drugs! Pharmacology: Reliable Sources of Information • Reference books (examples) – Physicians’ Desk Reference (PDR) – United State Pharmacopeia – Updated yearly Dose Forms • The manner in which the drug is prepared or transported into the human body • A single drug may have several dose forms • Determines speed or onset of the drug’s therapeutic effect. – Ex: tablets, capsules, suppositories Dose Forms - Tablets • • • • Most common oral dose form Compressed granules Easiest to administer Single dose units – May be scored – May be coated • to delay absorption or • protect mucosa Dose Forms - Capsule • Powder or liquid drug contained in a gelatin shell. • Can be time released Dose Forms - Inhalant • Can be used for local or systemic effects – Local – ex: asthma – Systemic – ex: general anesthesia Dose Forms – Suppository • Used for insertion into a body orifice – Ex: rectum, vagina • May have local or systemic effect Dose Forms – Solution • One or more drugs are dissolved in a liquid • Usually rapidly absorbed • May be administered orally or parenterally (injected) Dose Forms – Suspension • One or more drugs (small particles) are suspended in a liquid • Administered only orally • Must be shaken well Dose Forms – Transdermal patch • Permits drug application on the skin – Absorbed into the bloodstream Drug Administration – The 5 Rights 1. The Right Drug – Check the label 3 times! 2. The Right Amount 3. The Right Patient – Check the armband! 4. The Right Time 5. The Right Route Drug Administration – The 5 Rights • Read the label 3 times – Before drawing up, while drawing up, before administering to patient • Check expiration date • Discard cloudy solutions • Identify patient; explain what medication is being administered • Ask patient drug history • Do not leave unattended a patient who may be having a drug reaction Routes of Drug Administration • Oral – taken by mouth & swallowed into the stomach (PO) – Most efficient & most cost-effective method – Used if the drug will not be destroyed by secretions in the GI tract – Used when slower absorption & longer duration of drug activity are desired – Disintegrates & dissolves in stomach, then travels to small intestine where most absorption takes place – Patient must be conscious Routes of Drug Administration • Reasons for not giving drug orally – – – – – – – Unpleasant taste May cause nausea & vomiting May be destroyed by digestive juices May be danger of aspiration Patient may be uncooperative Rapid absorption may be desired May irritate gastric mucosa • May be given in enteric-coated form • Patients informed not to chew tablet before swallowing Routes of Drug Administration • Sublingual – drug is placed under the tongue; allowed to dissolve – Ex. Nitroglycerin tablets • Topical – application directly on the skin; absorbs through the bloodstream – Ex. Transdermal patch Routes of Drug Administration • • Administered by injection Requires aseptic technique and standard precautions • • 3 most common routes: Intramuscular (IM) 1. Subcutaneous (SC) 2. Intravenous (IV) Routes of Drug Administration • Subcutaneous (SC) – into the subcutaneous tissues • Intramuscular (IM) – into the muscle • Intravenous (IV) – into the vein • Intrathecal – into the spinal subarachnoid space • Epidural – into the spinal on or outside the dura mater surrounding the spinal column Routes of Drug Administration • Intra-articular – within the joint • Intra-arterial – into an artery • Pulmonary – into the lungs • Intradermal – beneath the skin surface – Ex: PPD test for TB Routes of Drug Administration • Subcutaneous – Administered below the epidermis – Absorption is through the capillaries at a fairly rapid rate – Dosage should be no more than 1-2 mL Routes of Drug Administration • Intramuscular – Absorption is variable depending on the drug & the muscle into which the drug is injected – Deltoid, gluteal, & vastus lateralis muscles are most frequently used – Deltoid – blood flow is more rapid than the gluteal muscles – Gluteal – larger amount of drug can be administered – Solutions absorb most rapidly – Suspension & oil-based emulsion absorb more slowly Routes of Drug Administration • Intravenous – Most rapid systemic response – no barrier to absorption – Method selected if rapid effect is desired or if drug cannot be injected into body tissues without damaging them – One of the most hazardous routes – reaction is immediate Routes of Drug Administration • Intrathecal, epidural, intra-articular, & intra-arterial – Used to achieve high local concentration of a drug for pain relief, treatment of neoplasms, to inject contrast media for diagnosis, or to administer anti-infective drugs – Intrathecal – bypass blood-brain barrier Routes of Drug Administration • Pulmonary – Used to administer drugs in the forms aerosols or gases – Used to assist with normal oxygen-carbon dioxide exchange in the lungs – Used to treat patients in respiratory distress Routes of Drug Administration • Topical – Used for local treatment of skin ailments as well as systemic treatment – When unbroken, skin is slow to absorb drugs into systemic circulation • Rate of absorption is accelerated if there is an open lesion or if the drug is applied to mucous membranes or to the area behind the ear (postauricular area) Routes of Drug Administration – Administered to the eye, nose, throat, respiratory mucosa, vagina, or sometimes rectum – Transdermal • Drugs applied to the skin for intended systemic effect • Absorbed slowly; constant blood level of the drug is achieved Equipment for Drug Administration • Needles – – – – Range in length from 3/8 – 2 inches for average use Longer needles used for special procedures Made of stainless steel Parts • • • • Hub – part that attaches to the syringe Shaft – elongated part of the needle Lumen – hollow tube that runs length of shaft Bevel – sharp, angulated tip of the needle Equipment for Drug Administration • Size of needle – Smaller the lumen, the larger the gauge of the needle • 18 gauge – lumen larger than 25 gauge – Viscosity of fluid determines the gauge selected – Area for injection & condition of patient determines the length of the needle chosen Equipment for Drug Administration Tip Barrel Plunger • Syringes – Vary in size from 1 – 60 ml – Parts of syringe • Tip – end of the syringe to which the needle is fastened • Barrel – body of the syringe • Plunger – inner part that fits into barrel – Calibrated in ounces & ml (cc’s) Equipment for Drug Administration • Needles & syringes – – – – – – Packaged to maintain sterility Some have safety locks to prevent needle-stick injuries Disposable – should not be reused Should be disposed of in sharps container Needles used on a patient should never be recapped Do not place used needles & syringes back onto tray to be disposed of later • Could cause potential needle-stick injury Equipment for Drug Administration • Angiocath is the safest device to use for venipuncture • After insertion, needle is extracted through a sheath • Less chance of accidental injury Packaging of Parenteral Medications • Packaged to maintain sterility • Small amounts – Ampules, vials • Larger amounts – Glass or plastic container Packaging of Parenteral Medications • Vial – Glass container with rubber stopper circled by a metal band – Band holds rubber stopper in place – Generally available in 5-, 10-, 20-, 30-, 50-mL sizes – On label • Name of med, dosage per mL, route by which it may be administered Packaging of Parenteral Medications • Cleanse top of rubber stopper with alcohol wipe • Draw air equivalent to the amount of fluid to be withdrawn from vial into syringe • Insert needle into vial & inject air in the syringe • Fluid in vial will replace air in syringe rather quickly • Plunger of syringe can be drawn back until exact amount of drug needed is obtained Packaging of Parenteral Medications • Ampule – Made up of glass & contains a single dose of a drug – Indented area at the neck can be opened by snapping it off with a sterile gauze pad – Label contains same info as vial – Single use only Packaging of Fluids & Medications for Intravenous Use • Large volume (50-1000 mL) packaged in either heavy plastic or glass containers – Plastic bags • Collapses under atmospheric pressure as fluid leaves • 2 ports – one for IV tubing, one to use if other drugs are to be added to the infusion – Glass bottles • Do not collapse • Must be constructed with an air vent so that air can replace fluid as it infuses into the vein • Rubber stopper like vial Abbreviations • Review common abbreviations in the text! Methods of Drug Administration • Parenteral Drug Administration – All equipment that penetrates skin must be sterile – Patient must be correctly identified – Explain procedure to patient; identify medication to be administered – Skin at injection site is cleansed with an antiseptic solution to be as free of microorganisms as possible Methods of Drug Administration • All persons administering parenteral drugs must wear gloves • Must be a physician’s order for medication • Five rights must be followed • Patient must be observed for 1 hour after drug administration for adverse or allergic reactions • Patient who has had a sedative, tranquilizing, or hypnotic drug may not drive him- or herself home Intradermal Administration • Also called intracutenous injections • Used for testing for sensitivity to a drug or antigen and local anesthesia administration – – – – Tuberculin syringe used Skin cleansed with alcohol Insert needle bevel side up at a 5-10° angle Inject drug – small raised area, or wheal, should be seen Subcutaneous Administration • Medications are injected into tissues beneath the dermis at a 45° angle • Tuberculin syringe may be used if amount is less than 1 mL • Given in the outer aspect of the upper arms, abdomen, scapulas, or the anterior thigh Intramuscular Administration • Chosen when prompt absorption of drugs is desired because there is a rich blood supply to muscles • Chosen when medication given SC would be irritating to the tissues & when a larger amount of a drug is needed – Amount of medication given = 1-5 mL Intramuscular Administration • Sites commonly used – Dorsal gluteal, ventrogluteal, rectus femoris, deltoid – Dorsal gluteal • Have patient in prone position with entire gluteal muscle exposed • Use iliac crest as superior boundary • Gluteal fold – inferior boundary • Divider buttock into 4 quadrants – Injection given into upper outer quadrant Intramuscular Administration • After cleansing site, place non-dominant hand on muscle to be injected to support patient • Quickly insert the needle into the muscle at a 90° angle • Aspirate to ensure no blood return – Blood return would indicate entrance into blood vessel • If no blood, inject fluid into muscle & quickly withdraw needle Peripheral IV Drug Administration • Immediate effect • One of the most hazardous routes – Drug is injected directly into circulatory system; reaction instantaneous • Must not leave a patient receiving an IV drug or contrast agent alone Peripheral IV Drug Administration • Piggyback – Small IV infusion which is attached to an adjoining or already existing line • Bolus – Designated amount of a drug that is administered at one time, over a period of several minutes • (Drip) Infusion – Larger amount of a drug, fluid, or fluid containing a drug or electrolytes that is administered over a longer period of time ranging from hours to days Peripheral IV Drug Administration • Extravasation (infiltration) – seepage of drug into the tissues surrounding the vessel. – – – – Immediately remove needle Apply pressure Apply warm moist heat to relieve discomfort If drug is corrosive, apply cold compress instead • Physician/pharmacy should be notified The Medication Order & Documentation • No health care worker may take it on him- or herself to prescribe or administer drugs that are not ordered by a person licensed to do so • 3 ways in which orders may be given by a doctor – Written, verbal, standing The Medication Order & Documentation • Order must be dated, written, & signed by physician • Info needed on an order – Patient’s full name, date, & time order is written – Date & time(s) that the drug is to be administered – Generic or trade name of drug – Dosage form & route of administration – Physician’s signature The Medication Order & Documentation • Stat orders – immediately • prn (pro re nata) – As the occasion requires – Standing order for pain medication • Single order – written for a medication to be given only once at a designated time Medication Errors • It is your legal & ethical obligation to be knowledgeable about any drug you feel competent to administer • If you administer a drug incorrectly or misinterpret an order from a physician, you are legally liable & have violated your code of professional ethics Medication Errors • Medication error or adverse reaction – Notify physician – Note in patient’s chart – Fill out incident report UNIT 5 Contrast Media and Introduction to Radiopharmaceuticals Chapter 21 Contrast Media • Purpose: To visualize anatomic detail in areas which lack inherent subject contrast; to increase the differential absorption of radiation in adjacent anatomic structures. • Contrast Media – agents instilled into body orifices or injected into various anatomic regions to enhance subject contrast – Classified as negative or positive Contrast Media • Positive contrast - high atomic number – Radiopaque - Increases x-ray absorption in the structure- Appears white on the image • Negative contrast - low atomic number – Radiolucent – Decreases x-ray absorption in the structure - Appears dark on the image – Often used in combination with positive contrast Negative Contrast Media • Composed of low atomic number elements • Administered as gas (air) or gas-producing tablets, crystals (carbonation) • Rarely used alone • Used in combination with positive contrast agents • Ex: Laryngopharyngography, air contrast barium enema Positive Contrast Media • Composed of high atomic number elements • Ex: Barium Sulfate (used primarily in GI tract imaging) • Ex: Water soluble Iodine (used in vascular, urographic and arthrographic studies. • Some complications/adverse reactions possible Barium Sulfate • • • • • • • Barium has atomic #56 Radiopaque Used to examine GI tract BaSO4 Not water soluble Suspension Flocculation – clumping; comes out of suspension • Administered orally or rectally • Mixed with cold (cool) water to reduce irritation, spasm and cramping • Often used with air Barium Sulfate • Contraindication: suspect perforation of GI tract; water soluble contrast is used instead • Complications: rupture; peritonitis; constipation; obstruction; Water Soluble Iodinated (Positive) Contrast Media • • • • Iodine has atomic # 53 Radiopaque Water soluble Most frequently used intravascular contrast agents contain iodine • Administered by injection (intravenous & intraarterial), orally, rectally • Adverse reactions possible – need allergic history • Ionic vs. Nonionic – Ionic results in more adverse reactions as compared with nonionic Water Soluble Iodinated (Positive) Contrast Media • Ex: Anaphylactoid effect (urticaria, wheezing, edema in throat/lungs bronchospasm, nausea, vomiting) • Increased risk for patients with renal disease/diabetes • Some drug interactions can cause contrast reactions – Ex. Beta blockers; calcium-channel blockers; Metformin (Glucophage) should be discontinued 48 hours prior to exam Water Soluble Iodinated (Positive) Contrast Media • Never leave patient unattended • Informed consent required • Contrast should be administered at body temperature • Excreted through kidneys - Instruct patient to increase fluid intake after procedure Oil-based Iodinated (Positive) Contrast Media • Insoluble in water • Viscous • Decompose when exposed to light, heat, air • Do not use plastic syringes • Disadvantage: persist in the body • Application: hysterosalpingography, bronchography, sialography, lymphography Reactions to Contrast Agents • Classifications of adverse reactions – Mild • • • • Complaints of itching of nose & eyes Anxiety Cough Hives or rash Reactions to Contrast Agents • Intermediate – Coughing that results from laryngospasm or angioedema of the upper respiratory tract leading to a feeling of tickling in the throat – Dyspnea & wheezing resulting from edema – Initial symptoms of shock • Anxiety, rapid pulse, rapid respirations, hypotension – Chest pain Reactions to Contrast Agents • Major – Shock – Seizures – Cardiac arrest • Vasovagal reaction – Patient experience high anxiety about procedure & its result – Symptoms include pallor, cold sweats, syncope, tachycardia or bradycardia, hypotension Patient Assessment & Care • Examples of history questions – – – – – Liver disease Kidney disease Hypersensitivity reactions (allergies) Heart disease Previous reactions Sponsored by: • This workforce solution was funded by a grant awarded under the President’s Community-Based Job Training Grants as implemented by the U.S. Department of Labor’s Employment and Training Administration. 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