Pharmacology PT020D Lecture 2

Course Objective #14 Identify medications commonly prescribed for D.D. clients by both generic and trade names.

Commonly prescribed meds Vitamins Cardiac meds Muscle relaxants Anti-anxiety Anti-convulsants

Course Objective #15 Describe the following mechanisms of drug action: – Altering existing cellular functions – Altering cellular environment

Alteration in Cellular Function Drugs CANNOT create new function! Drugs CAN alter existing cellular function

Receptor-mediated drug action Agonist – Enhances Antagonist – Blocks

What are the 2 types of Antagonists? Competitive Non-competitive

Drug Action Alter function AgonistAntagonistCompetitive Non- competitive Alter environment PhysicallyChemically

Alteration in Cellular environment Physically Osmotic pressure Lubrication Absorption Surface conditions Chemically Alter body fluids

Course objective #16 Differentiate between commonly used drugs according to: A.Name B.Classification C.Mechanism of action D.Indications for use E.Contraindications F.Adverse drug effects G.Drug interactions H.Drug incompatibilities

The name game Chemical name Generic name Official name Trade name / brand name

The NAME game ChemicalScientific terms – describes the molecular structure GenericGeneral name used by any company “non-proprietary” OfficialName given by FDA TradeSpecific company – marketing name

Classification “Class” Common action Frequently common – Side-effects – Adverse reactions

Mechanism of Action Pharmacodynamics – “The study of the drug mechanism that produce biochemical or physiologic changes in the body”

Mechanism of Action / Pharmacodynamics Admin. Rx  Systemic circulation  Entire body

Mechanism of Action 1 o Effect – Desired / therapeutic 2 o Effect – All other effects – + / - – “side-effects” – expected

Mechanism of Action Affinity for certain organs“Target Sites”Alt. functionAlt environment

Course Objective #17 Describe the following indications for use of drugs: – Primary – Adjunctive – Non-labeled use – Investigative use

Indications for Use Valid reason What is the opposite of indication? – Contraindication

Indications Primary – Main use

Indications Adjunctive – Used along with

Indication Non-labeled use – Supported by research

Indications for use Investigative use Only in FDA approved studies

Contraindication Published When to Avoid or D/C

Adverse Drug Reactions Undesirable Rx effects

Types of Adverse Rx effects Allergic

Adverse Drug Reactions Allergic Reaction – Hypersensitivity – Immune response “antigen” –  Anaphylactic Shock

S&S Anaphylactic Shock RespDyspnea, bronchospasm C/V  B/P +  P = Cardiac Arrest SkinUrticaria + Pruritus G/IN/V

Adverse Drug Reactions Rx Idiosyncrasy – Unusual reaction

Adverse Drug Reactions Rx Tolerance –  response to Rx

Adverse Drug Reactions Cumulative Rx Effect –  metabolism of Rx  –  levels

Adverse Drug Reactions Toxic Reaction –  levels  – Toxic / harmful

Adverse Drug Reactions Teratogenic – Rx + PG = – Congenital defects

Drug interactions Drug – Drug – When 1 Rx interacts with other Rx Drug - Food

Drug-to-drug Additive Rx reaction – = 2

Drug-to-drug Synergistic Rx reaction – = 3

Drug-to-drug Antagonistic Rx reaction – = 0 (or 1)

What should you do? You are mixing drugs in a syringe to give a parenteral injection when you notice white particles forming in the syringe. What should you do? Do NOT give the drug!

Drug-to- Food Food  – +/- absorption

Rx bottle reads: Take on an empty stomach What are the rules???? (tell your neighbor) – 1hr ac – 2hr pc

Rx bottle reads: Take with meals Minimize GI irritation

Insoluble Food-Rx mix Rx + Food = Insoluble – (Cannot be absorbed) –  absorption   effect

Course Objective #18 Explain how absorption, distribution, biotransformation and excretion effect: – The concentration of drug at body sites – The concentration of drug metabolites at body sites – The time for drug concentration to develop or change

Pharmacokinetics What the body does to the Rx – Absorption – Distribution – Metabolism Half-life – Excretion Biotransformation

Absorption How Rx is “made available” Most PO Rx are absorbed into the body from the…. – Small intestine

Factors that Affect Absorption Route Solubility

Distribution Rx carried from absorption site  tissue – *C/V system!

Course objective #20 Explain how distribution of a drug is effected by the blood-brain barrier.

Blood-brain Barrier Selective permeability Impermeable to MOST Rx

Hypertension Hyperosmolar Radiation Infection Trauma Development

Blood-Brain Barrier makes the brain impermeable to Most drugs

Metabolism What is the other name for Rx metabolism? – Biotransformation – Breakdown of the drug

Half-life Time required for body to eliminate 50% of the drug

Excretion Elimination of Rx from body

Explain how… Absorption Distribution Biotrans- formation Excretion Rx concentration in the body Effect

Course Objective #19 Describe how the rate of absorption of a drug is affected by: – Route of administration Oral Sublingual Parenteral Subcutaneous Intramuscular Intravenous – Interfering factors Stomach contents and acids Tissue problems at site of injection, topical, inhalant

2 biggest variables affecting absorption? Route Circulation

Categories of Rx administration Enteral Parenteral Percutaneous

Enteral Directly into GI – Oral – Rectal – Nasogastric

Parenteral Bypasses GI – Subcutaneous (Subcut) – Intramuscular (IM) – Intravenous (IV)

Percutaneous Skin – Inhalation – Sublingual – Topical

Enteral - With fluids – 8 oz water Food

Parenteral Correct tissue Reconstitute Assess tissue Heat  –  absorption Cool  –  absorption

Percutaneous Topical – Skin thickness – Hydration – Newborns   absorption Inhaled – Depth of breath – Fineness of droplet – Hydration

Course Objective #21 Describe how biotransformation facilitates elimination of drug metabolites.

Turn to your neighbor… Define the term biotransformation – Metabolism

Course objective #22 List the four body processes through which drugs or their metabolites are eliminated.

Course Objective #23 Explain how the following factors which influence individual pharmacological response: – Age – Gender – Body weight – Basal metabolic rate – Disease states – Genetic factors – Time/route – Tolerance – Nutrition – Smoking

Age Infant / Child – < dose Elderly – < dose – Polypharmacy

Gender Male vs. Female – Dose amount??? Male > Female – WHY???? – Fat:Water

Body Weight Dosing based on – 170 lbs

Basal Metabolic Rate  BMR  – __?___ dose – 

Disease State What diseases might effect pharmacological responses the most? – C/V Distribution – Liver Metabolism – Kidney Excretion

Genetic Factors

Time/Route Place the following in order of Speed: – IV – PO – IM – Subcut

Time/Route Place the following in order of Speed: – 1. IV – 4. PO – 2. IM – 3. Subcut

Tolerance What is the difference between drug tolerance and drug dependen ce?

Tolerance Requires  dose to produce same effect

Dependency AKA: Addiction – Cannot control ingestion – Physical Withdrawal – Psychological Emotionally attached

Nutrition

Smoking What effect does smoking have on BMR? – __?___ dosing

Course Objective #24 Calculate accurate medication dosages using dimensional analysis.