RNSG 1100 Pharmacology Course Lecture 2

All body functions, all disease processes and most drug actions occur at which level?

cellular level

Drugs are:

chemicals that alter basic processes in body cells

Drugs given for _________ must reach adequate concentrations in the blood and other tissue fluids surronding the cells

systemic effects

systemic effects

happens when a substance, medicine, or disease affects the entire body instead of just a single, small spot

Pharmacokinetics

• involves drug movement through the body to reach sites of action, metabolism, and excretion

• what the body does to a drug

Pharmacodynamics

what the drug does to the body

Local

a drug that acts where it is applied

Specific processes of pharmacokinetics include:

• absorption

• distribution

• metabolism

• excretion

ADME

Absorption

process that occurs from the time a drug enters the body to the time it enters the bloodstream to be circulated

Onset of drug action is determined by what?

rate of absorption

Factors that affect rate and extent of drug absorption

• dosage form

• route of administration

• administration site blood flow

• GI function

• presence of food or other drugs

Distribution

after a drug is injected or absorbed in the bloodstream it is carried by the blood and tissue fluids to its sites of action, metabolism and excretion

Metabolism

method by which drugs are inactivated or biotransformed by the body before they are excreted

Elimination

to have effective excretion there must be adequate function of the circulatory system and the organs of excretion (kidney, bowel, lungs and skin)

Most drugs are excreted by the _____ and eliminated in the ________

kidneys, urine

Agonists

drugs that produce effects like those produced by naturally occurring hormones, neurotransmitters, and other substances

Antagonists

drugs that inhibit cell function by occupying receptor sites. It prevents natural body substances and other drugs from occupying the receptor sites

Aspirin

wonder drug that treats pain, inflammation, and fever and helps to prevent blood clots

Aspirin is excreted through _____

the kidneys

Aspirin is absorbed in the ______ then distributed to all body tissues

GI tract

What does aspirin inhibit, and how does it act?

Aspirin inhibits prostaglandin cyclooxygenase (COX) and acts as an antagonist

What effects result from aspirin inhibiting prostaglandin cyclooxygenase?

Analgesic, anti-inflammatory, and platelet aggregation-inhibiting effects

How does aspirin help decrease fever?

It acts on the temperature-regulating system in the brain

What does aspirin promote to decrease fever?

Vasodilation and sweating, which help decrease fever

Serum half-life (elimination half-life)

time required for the serum concentration of a drug to decrease by 50%

Serum half-life is determine by what?

metabolism, excretion

Serum drug level

laboratory measurement of the amount of a drug in the blood at a particular time

Serum drug levels reflect:

• dosage

• absorption

• bioavailability

• half-life

• rate of metabolism

• excretion

Toxic concentration

• single large dose

• repeated small doses

• slow metabolism

Variables that affect drugs

• dosage

• route of administration

• drug-diet interactions

• drug-drug interactions

• age, weight

Physiologic

relates to the normal functions and processes of living organisms

Physiologic changes may alter all pharmacokinetic processes in:

older adults (65 and older)

Beers list

a list of medications where risks may outweigh benefits in older adults

Adverse effects

any undesired responses to medication administration

What drugs can produce adverse effects

all drugs

Black box warnings

strongest warning the FDA can give consumers to improve the safety of using drugs

Drug toxicity (poisoning or overdose)

occurs when there is an excessive amount of a drug and may damage body tissues

common in both adults and pediatrics

Activated charcoal is considered the “universal antidote” for

drug overdoses

What can drugs do to normal cellular activities?

drugs can stimulate or inhibit normal cellular activities, but they cannot change the type of function that normally occurs

Drug-related variables that affect drug action:

• dosage

• route

• drug-diet

• drug-drug interactions

Patient-related variable that affect drug action

• age

• body weight

• genetic and ethnic characteristics

• sex

• pathologic conditions

• psychological status

Rights of medication administration

• right drug

• right dose

• right patient

• right assessment

• right route

• right time

• right reason

• right to refuse the medication

• right documentation

• right patient education

• right evaluation

Preventing Medication Errors

• unit-dose system

• automated, computerized, locked cabinets

• computerized provider order entry

• bar coding

• limiting use of abbreviations

• computerized medication orders

• medication reconciliation

Dosage Forms

• regular

• chewable

• enteric coated

• extended release (XL)

• sustained release (SR)

• long acting (LA)

• sublingual

• buccal

Regular routes of administration

PO, gastrointestinal (GI) tube (crushed and mixed with water)

Chewable route of administration

PO colored and flavored/children

Enteric coated route of administration

PO dissolve in small intestine/used for meds that cause gastric irritation

Extended release (XL) sustained release, (SR) long acting (LA)

PO slowly absorbed, effects prolonged 12-24 hours

Sublingual

under tongue, dissolve quickly

Buccal

held in cheek, absorbed directly into the blood stream - rapid systemic effects

Oral route of drug administration

• Advantages: simple, convenient, inexpensive

• Disadvantages: unknown absorption and generally sloe drug action

Regular Capsules

• PO contain active drug, fillers, and preservatives (take with 8oz fluid)

• gelatin dissolves in gastric fluid and release medication

Extended release (XL); sustained release (SR), long acting (LA)

• slowly absorbed, effects prolonged 12-24 hours

• don’t bite, chew, or empty these capsules

Oral solutions

PO, GI tube absorbed rapidly, use appropriate measuring device

Parenteral solutions

• IV, IM, Sub-Q, intradermal Sterile, IV rapid effects, sub-q for heparin and insulin, IM few drugs, intradermal inject skin test.

• Insulin syringe for insulin, TB syringe for measuring small amounts

Suspensions

PO, sub-q

e.g.; NPH insulin - rotate or shake

Dermatologic Creams, Lotions, Ointments

minimally absorbed through skin and exert local effect

some (ex: skin patches) exert systemic effects

dispose properly

Solutions and powders for oral or nasal inhalation including metered dose inhalers (MDIs)

oral inhalation mainly for asthma, nasal sprays for allergic rhinitis, deliver specified dose

correct use essential

Eye solutions/ointment

sterile, can have systemic effects

Throat Lozenges

cough and sore throat

Ear solutions

ear infections

Vaginal creams and suppositories

vaginal infections

Rectal suppositories and Enemas

suppositories: sedative, analgesic, laxatives

enema: constipation or inflammatory bowel diseases

The rate of absorption depends on the ______

route

GI tubes (e.g.; nasogastric, gastrostomy)

Advantages: uses GI tract, avoid injections

Disadvantages: aspiration, clogging

Proper precautions and preparations. Liquid preferred over crushed and emptied capsules. If crushing, give meds one at a time and don’t use long-acting formulations. Tube should be rinsed before and after med. Request liquid form of drug where possible

Subcutaneous (SQ)

Advantages: small, less painful needles used (insulin, heparin)

Disadvantages: small amount of drug (up to 1 mL), slow absorption

irritating to sub-Q tissue-pain, risk of necrosis and abscess

Intramuscular (IM)

Advantages: rapid absorption

Disadvantages: small amount can be given (up to 3mL)

risk to blood vessels or nerves

use anatomical landmarks for sites

Intravenous (IV) Directly into blood stream

Advantages: bypass barriers, rapid action

Disadvantages: skill needed, phlebitis and thrombosis, increased risk of adverse reactions

gloves worn, prevent damage to sites

Topical skin or mucous membranes: nasal or oral inhalation, instillation into lungs, eyes, or nasal under tongue (sublingual) into cheek (buccal); into vagina or rectum

Advantages: intact skin-site of application. Some drugs given topically for system effects )ex: mucous membranes-rapidly absorbed)

Disadvantages: irritation to skin or mucous membranes. Mucous membranes may cause systemic effects

Preferred over oral or injected - fewer and/or less severe systemic effects

Parenteral

by some other means than through the gastrointestinal tract

Parenteral administration methods

• intramuscular (IM)

• subcutaneous (subq)

• intradermal (ID)

• intravenous (IV)

Subcutaneous Injection sites

Anatomic Landmarks and Intramuscular Sites

Intramuscular insertion angle

90 degrees

many vaccines

Subcutaneous insertion angle

45-90 degrees

insulin, heparin

Intradermal insertion angle

15 degrees

TB skin tests