PT Care LEC 6: Introduction to Pharmacology

Introduction to Pharmacology

• Pharmacology is the study of drugs and their actions on the body.
• The general objectives include defining and describing pharmacology, pharmacokinetics, pharmacodynamics, pharmacy and toxicology, sources of drug information, drug names, FDA, drug sources, pharmacological agents, function and examples, adverse reaction & side effects, universal precautions in drug administration, the prescription and drug order, common forms of medication, drug administration, controlled substance act -1970, posology, and pharmacology abbreviations.
• A drug is any substance or product used to modify physiological systems or pathological states for the benefit of the recipient.
• "Poisons in small doses are the best medicines; and useful medicines in too large doses are poisonous" - William Withering 1789.

Pharmacokinetics and Pharmacodynamics

• Pharmacokinetics describes what the body does to a drug, involving absorption, distribution, metabolism, and excretion (ADME).
• Pharmacodynamics refers to what a drug does to the body.
• Pharmacology includes pharmacotherapeutics, pharmacy, and toxicology.
• Pharmacotherapeutics involves treating disease through drug administration.
• Pharmacy focuses on preparing suitable dosage forms and dispensing medication.
• Toxicology studies the adverse effects of toxins on living organisms.

Sources of Drug Information

• A pharmacopoeia is an official publication listing medicinal drugs with their effects and directions for use
• USP (United States Pharmacopoeia) is a drug standard.
• BP is the British Pharmacopoeia.
• WHO Pharmacopoeia is from the World Health Organization.
• USP-NF (United States Pharmacopeia - National Formulary) contains public pharmacopeial standards for chemical and biological drug substances, dosage forms, compounded preparations, excipients, medical devices, and dietary supplements.
• The Physicians' Desk Reference (PDR) is a compilation of manufacturers' prescribing information, updated annually.

General Uses of Medications

• Diagnostic medications allow for better visualization during a procedure.
• Prophylactic medications are intended to prevent disease.
• Replacement medications replace substances normally found in the body.
• Therapeutic medications restore the body to a pre-symptom state.
• Curative medications seek to cure a disease or illness entirely.
• Palliative medications aim to improve quality of life and relieve pain, focused on comfort, not cure.

Drug Names

• Chemical names state the chemical composition and molecular structure.
• Generic names are selected by the manufacturer during development and assigned by USP/NF, usually being the official name. The generic name for MotrinⓇ is ibuprofen.
• Brand names are trade or proprietary names copyrighted by the manufacturer, followed by ®. The brand name for ibuprofen is MotrinⓇ.

Federal Food and Drugs Agency (FDA)

• The FDA is a government agency established in 1906 through the Federal Food and Drugs Act.
• The original act focused on standards for quality and labeling.
• When a pharmaceutical company first develops a new drug, it is initially sold under a trade name under patent protection for around 20 years of profit.
• Once a patent expires, the drug can be manufactured and sold by other companies as a generic drug with a much reduced price.
• FDA guidelines mandate that generic drugs must be identical to the branded drug in efficacy, safety, usage, route of administration, pharmacokinetics, and pharmacodynamics.

New Drug Development Timeline

• Pre-Clinical Testing, Research and Development
• Phase 1: Clinical pharmacology
• Phase 2: Clinical investigation
• Phase 3: Formal therapeutic trials
• Phase 4: Post licensing (marketing) studies
• Clinical Research and Development
• NDA Review
• Post-Marketing Surveillance

Placebos

• Placebos are devoid of intrinsic pharmacological activity; their effects are psychological (suggestibility).
• Placebos are used in clinical research.

Drug Sources

• Mineral: liquid paraffin, magnesium sulfate, etc.
• Animal: insulin, thyroid hormones, etc.
• Plant: morphine, quinine, digoxin, etc.
• Synthetic: aspirin, sulfonamides, etc.
• Micro-organisms: penicillin, cephalosporin & other antibiotics.
• Drugs produced by genetic engineering: human insulin, human growth hormone, etc.

Pharmacokinetics - ADME

• Absorption: How a drug moves into the bloodstream from the administration site.
• Distribution: How much a drug is moved to various body tissues and organs, depending on blood flow.
• Metabolism: How a drug is altered or broken down.
• Excretion: How a drug is removed from the body.

Absorption Factors

• Biological membranes affect the route of administration.
• Oral Preparations, from Fastest to Slowest: Liquids, elixirs, syrups, suspension solutions, powders, capsules, tablets, coated tablets, enteric-coated tablets
• GI tract absorption occurs through mucous membranes.
• Topical absorption occurs through the skin.
• Intramuscular absorption happens through muscle tissue.

Distribution

• Distribution is a branch of pharmacokinetics describing the transfer of a drug from one location to another within the body.
• The cardiovascular system is the main system for medication distribution.

Metabolism Details

• Metabolism is also known as biotransformation, converting one chemical form to another for easier excretion.
• The liver is the main organ for drug metabolism.
• Other tissues with metabolizing enzymes include adipose tissue, intestines, kidneys, and lungs.
• Metabolism can inactivate drugs or convert inactive drugs (prodrugs) into active forms.
• Not all drugs undergo metabolism.

Key Metabolic Effects

• Genetic factors: Variations in genes can affect enzyme activity, influencing drug metabolism.
• Age: Newborns and the elderly often have slower drug metabolism due to immature or declining enzyme systems.
• Sex: Hormonal differences between males and females can impact drug metabolism rates.
• Health Conditions: Liver diseases, kidney dysfunction, or other illnesses can impair the body's ability to metabolize drugs.
• Diet and Nutrition: Certain foods and nutrients can either enhance or inhibit drug metabolism.
• Drug Interactions: Concurrent use of multiple drugs can lead to competition for metabolic enzymes, altering the metabolism rate.
• Environmental Factors: Exposure to toxins or chemicals can affect enzyme activity and drug metabolism.

First Pass Metabolism

• First-pass metabolism reduces drug concentration before systemic circulation.
• Swallowed drugs travel from the digestive system to the hepatic portal system and the liver for metabolism before entering the rest of the body.

Bioavailability

• Bioavailability is the fraction of an administered drug dose that reaches systemic circulation in an unchanged form.
• Oral Drug Dose: Destroyed in gut, Not absorbed, Destroyed by gut wall, Destroyed by liver, to systemic circulation

Effect of First-Pass Metabolism

• First-pass metabolism is a phenomenon where drug concentration is greatly reduced before reaching systemic circulation.
• Medications given orally are typically exposed to significant first-pass metabolism.
• First-pass metabolism reduces bioavailability.
• Nitroglycerin is given sublingually or parenterally to avoid being inactivated by first-pass metabolism.

Excretion Routes

• Drugs and/or their metabolites are irreversibly eliminated from the body
• Kidneys: They are the main route for many drugs, including Contrast Madia
• Liver Bile
• GIT - Stools
• Salivary glands - Saliva
• Skin - Perspiration, sweat
• Eyes - Tears
• Lungs: breathing - Volatile medications

Drug Half-Life (t1/2)

• Half-life is the time required to reduce plasma concentration to 50% of its original value.
• Half-life determines dosing requirements, and it also determines how long a drug will remain in the body.
• Half-life is used to determine dosing intervals to keep a steady drug level (plateau).
• After 1 half-life, 50% of the drug is eliminated; after 2 half-lives, 75% is eliminated; after 3 half-lives, 87.5% is eliminated; after 4 half-lives, 93.7% is eliminated.
• Nearly complete drug elimination occurs in 4-5 half-lives.
• If a drug's half-life is 2 hours, complete elimination occurs in 8 - 10 hours.

Pharmacodynamics: Agonists vs. Antagonists

• Pharmacodynamics studies what the drug does to the body.
• It quantitatively studies the biological and therapeutic effects of drugs.
• Drug + Receptor = Effect
• Drug + Receptor = Maximum Effect
• Drug = Full Agonist
• Drug + Receptor = Less than maximal effect
• Drug = Partial Agonist
• Drug + Receptor = Block Effect
• Drug = Antagonist

Drug Combinations

• Addition (1 + 1 = 2): The effect of two drugs equals the mathematical sum of their effects.
• Synergism (1 + 1 = 3): Two drugs with the same effect produce a response greater than the sum of individual responses.
• Potentiation (0 + 1 = 2): A drug with no effect enhances the effect of a second drug.
• Antagonism (1 + 1 = 0): A drug inhibits the effect of another drug; the antagonist has no inherent activity.

Pharmacological Agents Functions and Examples

• Analgesics relieve pain without causing loss of consciousness (e.g., acetaminophen/Tylenol).
• Anesthetics produce a lack of feeling locally or generally (e.g., lidocaine/Xylocaine).
• Antibiotics destroy or inhibit the growth of harmful microorganisms (e.g., ciprofloxacin/Cipro).
• Antidiabetics lower blood sugar or increase insulin sensitivity (e.g., insulin/Humulin).
• Antifungals destroys or inhibits fungal growth (e.g., ketoconazole/Nizoral).
• Antihistamines slows allergic reactions (e.g., diphenhydramine/Benadryl).
• Nonsteroidal Anti-inflammatory drugs counteracts inflammations (e.g., ibuprofen/ Motrin, Advil).
• Antivirals controls the growth of viral microorganisms (e.g., zidovudine/ AZT, Retrovir).

Other Medication Classifications

• Antihypertensives decreases blood pressure.
• Anti-infectives treats infections.
• Bronchodilators dilates the bronchi and bronchioles.
• Diuretics increases excretion of water/sodium.
• Laxatives loosens stools and increases bowel movements.
• Miotics constricts pupils of the eye.
• Mydriatics dilates the pupils.
• Narcotics/analgesics relieves pain.
• Antacids reduces hydrochloric acid in the stomach.
• Antianemics increases red blood cell production.
• Anticholinergics decreases oral secretions.
• Anticoagulants prevents the formation of clots.
• Anticonvulsants manages seizures or bipolar disorders.
• Antidiarrheals reduces water in bowels/ gastric motility.
• Antihistamines blocks the release of histamine.

Adverse Drug Reactions

• Adverse Reaction:
  • Adverse reactions are unpredictable responses to a drug.
  • Adverse reactions include drug-induced allergies.
  • They can be harmful, noxious, unintended, and undesirable.
  • Some adverse reactions are life-threatening.
• Side Effect:
  • Side effects are unavoidable, unintended but predictable pharmacodynamic effects that occur at a therapeutic dose.
  • An example is flushing with contrast media.

Additional Adverse Reaction Types

• Drug Allergy:
  • It may involve an immune response that lead to an allergic reaction.
  • An example is an allergy to penicillin or contrast media.
• Idiosyncrasy
  • It is an unusual adverse reaction to a drug in most patients, it is unpredictable and can be life-threatening
• Toxic Effects:
  • Toxic effects result from excessive pharmacological action due to overdose or prolonged use. -Hepatic necrosis from acetaminophen (Tylenol) overdose
• Drug intolerance are toxic effects from a drug individual that causes vomiting.
• Drug Tolerance:
  • Over time the drug causes a decreased response after repeated administration.
  • This happens with narcotic analgesics (morphine or fentanyl).
• Tachyphylaxis:
  • Rapidly occurring tolerance to a drug.
• Cumulative effect is increased effectiveness when a drug is given in several doses. It is found with digoxin and amiodarone.
• Drug dependence is when the body has accustomed to the drug is there in the body. Narcotic analgesics (fentanyl)

Mutagenic and Photosensitivity Effects

• Mutagenic alterations of the genotype.
• Cyclophosphamide
• Photosensitivity is when cutaneous reaction resulting from drug-induced sensitization of the skin to UV radiation. Quinolones

Teratogenicity

• Teratogenicity is the ability of a drug to cause fetal abnormalities or birth defects.
• One example is Thalidomide (katergan).
• Pocomelia can result when exposed to Teratogenicity.

Additional Pharma Definitions

• Over-the-counter (OTC): sold without a prescription.
• Legend drug: requires a prescription.
• Pharmacist: dispenses prescription drugs.
• Indication: the approved use for a drug.
• Contraindication: a medical condition making a drug inadvisable.

Six Rights of Medication Administration

• Right Drug
• Right Dose
• Right Patient
• Right Route
• Right Time
• Right Documentation including patient response.
• Remember, contrast agents are drugs!

Documenting Medication Administration

• Name of drug
• Dose
• Route
• Time & Date
• Technologist initials & signature
• Response of the patient.

Precautions in Drug Administration

• All drugs are potentially harmful.
• Never be careless while administering drugs.
• Administer drugs, as prescribed, understanding action
• Adhere to the Six Rights of drug administration.

Other Precautions

• Read the label carefully at least 3 times before administering.
• If the medication is in cloud form or has sediment discard it
• Check Expiration dates and discard if Expired
• Don't administer left over Medication unless there is a multiple use
• Check allergies of patient before
• Don’t leave patient unattended when having reaction.
• Patient must not drive .
• Child that's sedated may not leave until fully awake.
• Observed patient for an hour prior to release.
• Not administered a drug that not prepared
• Document drug with details.

Medication Errors

• health care workers take responsibility for their actions and if drug and or order is incorrect and or misinterpreted radiographer will bare the liabitliy

Prescription Information

• Superscription: date, patient name, address
• Inscription: name and quantities of medication
• Subscription: directions to pharmacist
• Signatura: directions to patient
• Doctor signature, address, registry #
• Doctor DEA # for controlled substances

Drug Order

• A written order in a hospital or inpatient facility
• patient name, hospital name, birthdate, date, and time of order, name of drug, dosage and how delivered, and signature of the doctor or professional

Verbal Order

• All telephone and face-to-face orders
• Authorized prescriber
• Licensed individual who receives order
• Cosigner/authenticator

Common Medication Forms

Tablets- chews or dissolved
Capsules- shells that contain in liquid Liquids- solutions for those with swallowing Topical - creams, lotions, gels Inhalers and Nebulizers- delivered to lungs Injectable- injections Suppositories- rectum or vagina and urethra Patches -adhesive transdermal skin Sublingual - against cheek or tongue

Drug Formulations

• Elixir- oral liquid dissolved in alcohol
• Tincture- topical liquid dissolved in alcohol
• Solution- drug dissolved in liquid
• Suspension- drug particles suspended in liquid that you must shake well before administration
• Emulsion- drug particles with oil or fat in the water
• Lozenge- drug in a candy-like base, dissolves slowly and coats the oral pharynx
• Syrup- oral liquid drug in a thick solution

Drug Administration Routes

• Enteral Route
• Parenteral Route
• Topical Route

Topical Methods

• Skin
• Intranasal
• Eyes
• Ears
• Mucosal
• Inhalational
• Transdermal

Types of Drugs

• Systemic: Travels through the bloodstream . ( Entreal/Parenteral transdermal patches, Inhalation
• Local: Affects only a certain area. ( concentration and absorption negligable

Routes

• enteral oral
• enteralsublingual
• enteral buccal
• enteral rectal

Oral Route Details

• Oral administration involves swallowing for absorption along the gastrointestinal (GI) tract into systemic circulation.
• Common dosage forms include tablets, capsules, and liquids.
• The abbreviation "po" (per os) indicates the oral route. Advantages to administration: Convienent, Absorbs down tract, Cheap Disadvantages of administration: Too slow of efffect, can't use on unconscious person, soem drugs are are ruined(insulin), 1st past affects and destroyed drugs

Sublingual administration

• When dosage against tongue for rapid absorbance Advantages: Economical , no first past effect Disadvantage: Bitter , oral mucosa irritation and limited of drugs are applied

Buccal Administration

• Dosage placed against gums Advantages: avoid first past effect, rapid absorption, and keep drug stability Disadvantages: advantages lost with small dose

Rectal Route

• Drugs placed through rectal and high concentration Advantages: good for unconcious patient, faster results limited first past effect/vomitting Disadvantages: term long use not recommended

Parenteral Injection Types

• Intradermal (ID) injection into skin dermis
• Subcutaneous (SC) injection into SC tissues
• Intramuscular (IM) drug injected into skeletal muscle
• Intravenous (IV) placing drug directly to bloodstream

IM Injections

-Injection to the muscle

• Prompt absorbtion
  -The usage sizes are 18-to23 1to1.5-inch

Intradermal Injections

• The Tuberculin syringe is used and tested for 5_to 15%
• Used to inject at 25to257 1/2 inlength

Subcutaneous injections

• Hypodermal is involved and it's injecti fatly tissue and used 45 degree

IM -Intramuscular injection sites

• deltoid/gluteus maximus are used

Injection Methods

• Intraeteral: the drug that is through bloodstream that used 30-60 time until affect and can use intramuscular Subq and transdural

Needle Gauge Explanation

• The size of the size of the lumen affected by fluid inject determine the length and the smaller size the bigger the gauge 30 gauge is snaller than 12.

IV (Intravenous)

Median Cubital vein 1 Cephalik vein 2nd option Basilix is 3 option Anterior to the Wall of the bevel

IV (Intravenous): Advantages and Disadvantages

• Advantages: BBA and blood concentraction is achieved and large Q
• Disadvantages: infection and nerve damage with assist and not much affordable , and lead cellulist and faster reaction

Intravenous

• extraversation due a small are in neesed area with compresess and stoppage immediately after with swelling and hotness

Injection Details

• IV the used in push IV or direct , and IV for slow delivery , with PUMP to control rate delivery and DIP uses the flow

Medication Containers

• One time use for Ampules, and dispose of that
• For multi use use viols with rubber and discard if precipitation or damage

Effects after Injection

• Iv takes 30-60 second and intermusculares has 10to 20 minutes sub Q after that and oral for long times with 30 up to 90 Minutes -transudural are variable and depend of time

Stocked Carts

• crash cart is fully stocked and located in everywhere because it the contrast and need a quick response