Pharmacology: The Study of Drugs

Pharmacology:

• Pharmokinetics: Study of how the body absorbs distributes and eliminated chemical compounds

• Pharmacodynamics: investigation of how the drug affects the body and how it exerts its effect

Drug Nomenclature• Drugs can be identified according to:

– Chemical name: refers to the specific chemical structure of the compound

– Generic name: official “nonproprietary” name (often shorter and derived form the chemical name

– Trade Name: name assigned by the drug manufacturer

• Several companies may make an identical generic product but assign different names to it (Advil, Motrin)

Drug Classifications

• Over-the-counter: The type of drugs you, yourself may by in the drug store – Ibuprofen, Aleve7, Aspirin etc.

• For minor problems

• Prescription: The type of drugs a Dr. must give you a prescription for (monitored and distributed by pharmacists, must have a license to dispense)– Prednisone, Cortisone, Naprosen

Prescriptions

• Prescriptions are further classified according to their potential for abuse – called controlled substances– Further divided into schedules I-V (V has the

lowest relative abuse potential)– All controlled substances has laws defining

distribution

Methods of Drug Administration: Enteral (alimentary)

• Enters body through digestive system– Oral medication (metabolized through the liver)– Sublingual– rectal

Advantages of Enteral Drug Administration

• Oral - easy

• Sublingual– Rapid onset– Don’t have to pass through the liver for

metabolism

• Rectal - Alternate for Oral if stomach problems

Disadvantages for Enteral Drug Administration

• Oral– absorbed in the intestine - if not liquid soluble

may cause stomach pain– absorption rate varies– Passage through liver may nullify effects

• Sublingual: must be soluble in fatty tissue/mucosa

• Rectal: Incomplete absorption

Drug Administration: Parenteral

• Inhalation

• Injection

• Topical/Transdermal application

• Effects occur within 15 seconds

Drug Absorption

• Bioavailability: the extent to which (expressed in %) the drug actually reaches the blood stream– Further distribution entails crossing cell

membranes, tissue barriers to the target tissue– Greater blood flow around target tissue greater

amount of drug into target tissue.

Drug Absorption Cont.

• Passive diffusion: Drug moves from areas of higher concentration to lower concentration

• Lipid diffusion: ability of drug to pass through lipid portion of cell membrane (degree of lipid solubility will allow access to many tissues)

Drug Absorption Cont.

• Most drugs are weak acids or bases: have the ability to become negatively or + charged depending on the PH of body

• Compounds must diffuse in cell junctions (spaces between cells): – Blood Brain Barrier: spaces may allow or prohibit

passage example capillary walls of brain impenetrable to liquid solubles but permeable to lipid solubles

– This is why the more lipid-soluble the drug is the more tissues are affected

Drug Elimination

• Occurs through either: Metabolism or Excretion

• Metabolized– Chemically changed into compounds that are less

effective and more water soluble– occurs primarily in the liver but also in the lungs,

kidneys, GI or skin.– Conditions that alter these sites may alter the

elimination of the drug

Two Factors Considered in Drug Elimination

• Drug interactions: drugs which when metabolized stimulate or depress the metabolism of other drugs

• Drug tolerance: drugs when used over a prolonged period are metabolized more rapidly than normal

Drug Half Life• Half Life: The amount of time needed to reduce the

drug concentration to 50%– This is important to understand how often the drug can be

administered

• 5 Half Lives - a steady state wherein the amount administered is = to amount eliminated

• Loading dose: first administration of the drug is twice the normal dose to allow concentration levels to reach effective levels more rapidly (example prendizone)

Pharmacodynamics

• Agonist drugs: act with the receptor site to produce an effect (drug acting to increase the normal activity of the cell).

• Antagonist drug: acts to suppress the activity of the cell (activity that is the cause of discomfort or disorder)

• Efficacy: how well the drug does the above

Pharmacodynamics

• Potency: not-related to effectiveness - may have the same effect as another drug but requires a smaller does

• Tolerance: cells have built up a resistance requiring increased amount of the drug to achieve the same effects.

• Side Effects: non-desired effects of a drug

• Drug Allergy: itching, burning, skin rash or severe reactions (anaphylactic shock)

Common Drugs in Athletic Training

• NSAIDS

• Antispasmodic

• Asthma Medications

• Gastrointestinal distress

• Dermatologic Medications

• See common drugs chart

NSAIDS

• Antipyretic: fever reducing (Asprin, acetaminophen)

• Anti-inflammatory (ibuprofen, naproxen)

• Analgesic

• All decrease prostaglandin synthesis: primarily responsible for causing pain and inflammation– Also been found to decrease

neutrophils (decrease collagen synthesis possible weakness result),

NSAIDS: Contraindications

• Over 60 years old

• History of peptic ulcers

• high doses of NSAIDS or more than one

• smoking

• heavy alcohol consumption

• Current use of corticosteroid

• taking anticoagulants

NSAIDS: Salicylates• Properties

– Analgesic, antipyretic, anti-inflammatory, antiplatelet’

• Types– Asprin– Choline Salicylate (Athropan)**– Magnesium Salicylate (Doan’s, Mobidin)**– Sodium Salicylate (Alka Seltzer)**– **These are methods of absorption

NSAIDS: Salicylates• Topical Salicylates: Icy Hot, Ben Gay, Myoflex

(used to relieve pain)

• General Dose:– 650 mg every four hours within 24 hours not to exceed

4000mg

– loading does of 975 mg may be acceptable for fast pain relief

– Chlorine Saliculate 435-870 mg every 4 hours

– Magnesium Salicylate 377-754 mg every 4 hours

– Sodium Salicylate 325-650 mg every 4 hours

Side Effects of Salicylates:• Gastrointestinal

• Hemtologic Effects

• Nephotoxicity

• Allergic reactions

• Reye’s Syndrome (viral infections in children)

• Overdose (coma, circulatory failure, respiratory failure)

• Found to have no effects on athletic performance

NSAIDS Non-Salicylate

• for relief of headache, myalgia, arthralgia

• Three types– ibuprofen (Advil7)– Ketoprofen (Ketopron7)– naproxen sodium (Aleve7)

CO2H

CH3

H3CO

naproxen

CO2H

CH3

ibuprofen

O

CO2H

CH3

ketoprofen

NSAIDS Nonsalicylate

Generic Name Duration RX/OTCDiclofenac (cataflam,voltaren)

Short RX

Etodolac (lodine) Short RX

Fenoprofen (Nalfon) Short RX

Ibuprophen (Advil, Motrin,Nuprin)

Short Rx/OTCC

Idomethacin (Indocin) Intermediate RX

Flurbioprfen (Ansaid) Short RX

NSAIDS Nonsalicylate

Generic Name Duration RX/OTCKetorolac (Toradol) Short RX

Mefenamic acid (ponstel) Short RX

Naproxen (Alieve, Naprosyn) Intermediate RX/OTC

Nabumetone (Relafen) Long Rx

Idomethacin (Indocin) Intermediate RX

Piroxicam (Feldene) Very Long RX

Oxaprozin (Daypro) Long RX

NSAIDS Nonsalicylate

• General Does 200 mg tablets

• 400 mg every 4-6 hours not to exceed 1200mg

• Side Effects– Similar to Sailcylates (no reye’s syndrome)

• Not Banned by any athletic governing bodies

• No effect on athletic performance

Anti-inflammatory Drugs: Corticosteroids

• Corticosteroids: steroid hormones from adrenal cortex (may be synthetic)

• Anabolic steroids: derivations from testosterone

• Corticosteroids: exert their influence in the cytoplasm of affected cells, affective DNA transcription of selected genes.– Researchers believe the drug allows the attraction of

leukocytes into the affected area

Corticosteroids

• Indications:Skin disordersNasal inflammationRespiratory ailmentsRheumatic disordersChronic inflammation

Corticosteroids

• Administration– Oral (nasal infections, respiratory ailments)– Injection (chronic inflammation)

• Athletic Governing bodies have strict regulations of its usage

Corticosteroids

• Side Effects– Optic - eye pain– Gastrointestinal– Circulatory: lasting skin hives, discoloration,

burning itching– Menstral irregularities– Softening of cartilage (Delayed - over time)

Non-Anti-Inflammatory Systemic Analgesics

• acetaminophen (Tylenol) analgesic OTC/RX mild to moderate pain

• Opiate Agonists - for severe pain– Morphine– Codeine– Tramadol (Ultram): for moderate to severe pain– Combination products for mild to moderate

pain (Tylenol with codeine)

Non-Anti-Inflammatory Systemic Analgesics

• (Flexifil, Robaxin, Soma): muscle relaxants, decrease spasm

• all cause drowsiness• Good in combination with NSAIDS• Side Effects

– drowsiness– overdose– addiction (opiates) - and/or tolerance

Asthma Medications:

• Beta 2 agonists: relax smooth muscle – bronchiodialazters– risk drug interactions due to protein bonds

• Corticosteroids: Inhaled or Oral– Oral is for severe asthmatics– adverse reactions only 10-20% reach bronchi– Take more than 1-2 doses can cause opposite

effects

Asthma Medications:

• Cromolyn: few side effects for prevention only– acts by inhibition of bronchiole constriction– beneficial for prevention, not attack

• Leukotrienes, Anti-cholinergics, Theophyllines– Not effective for prevention– for severe asthmatics– only 10-20% reach bronchi

Asthma Medications - Consideration for Use

• Heart disease

• Other prescription medications

• If OTC drugs are ineffective within 1 hour seek prescription

• Banned substances

Asthma Medication Side Effect• Coughing after the use of any inhalers is common• Beta-2 agonists: “jitters” irritation irritability,

tachacardia (specifically after repeated use), tolerance

• Orally administered Leukotrienes, Anti-cholinergics, Theophyllines can be extremely toxic resulting the seizures and cardiac arrhythmia.

• Ephedrine: may cause heart attacks seizures and psychosis

GI Distress

• H2 blockers prevent acid secretion (Tagamet, Zantax, Pepcid)– May use pre-participation– May be beneficial in preventing “stitch”

• Antacid

Dermatological

• Antifungal (topical cortizone)

• Anti-virus (herpes)

• Anti-bacterial (ringworm)

• Anti-viral and bacterial are prescription medications