Pharmacology Quiz 1 (CH 1-5)

Pharmacology

study of drugs that alter functions of living organisms

Drug therapy

used of drugs to prevent, diagnose, or treat signs, symptoms, and disease processes

Medications

drugs given for therapeutic purposes

-given for local or systemic effect

Type of effects of medications

local and systemic

Local

act mainly at the site of application (ex: sunscreen, hydrocortisone creams)

Systemic

taken into the body, circulated via the bloodstream to sites of action in various body tissues (ex: intravenous antibiotic therapy)

T/F: Pharmacology is the use of drugs to prevent, diagnose, or treat signs, symptoms, and diseases.

False

Pharmacotherapy (clinical pharmacology)

The use of drugs to prevent, diagnose, or treat signs and symptoms and diseases

- Focuses on the drug effect on the body and the bodies response to the drug**

Drug sources

plants, animals, minerals, synthetic compounds, semisynthetic

Synthetic compounds

•manufactured in laboratories

•More standardized in chemical compounds, more consistent in affect, less likely to produce allergies

Semisynthetic

naturally occurring substances that have been chemically modified

ex: many antibiotics

Classifications

classified according to effects on

- specific body systems (ex: morphine- CNS depressant)

- therapeutic uses (ex: morphine- potent analgesic)

- chemical characteristics (ex: morphine- narcotic)

** drugs often overlap classifications

Prototypes

Individual drugs that represent groups of drugs

- Often the first drug of a particular group to be developed

* Ex: morphine (represents opioid analgesics)

* Ex: penicillin (represents beta-lactam antibacterial drugs)

Drug names

chemical name, generic name, brand/trade name

T/F: Over-the-counter medications are not regulated by law.

False

Prescription

Written by a licensed health care provider, such as a physician, dentist, or nurse practitioner

Over-the-counter (OTC)

- drugs available without a prescription

- regulated by various laws

Orphan drugs

Drugs that are not financially viable and not adopted by a drug company.

Which law (and its amendments) requires that official drugs meet standards of purity and strength?

Food, Drug, and Cosmetic Act of 1938

Controlled Substances Act (1970)

-regulates manufacturing and distribution of narcotics, depressants, stimulants, hallucinogens, and anabolic steroids

-developed categories for ranking the abuse potential of various drugs

Drug Enforcement Administration (DEA)

- Enforces Controlled Substances Act

- Registers individuals and companies legally empowered to handle controlled substances

- Regulates documentation and handling of controlled substances

Schedule 1 drugs

- Highest potential for abuse

- no currently accepted medical use in the U.S.

- Lack of accepted safety for use of the drug under medical supervision

Schedule 2 drugs

• High abuse potential

• Accepted medical use

• Severe physical and/or psychological dependence

Schedule 3 Drugs

- potential for abuse less than schedule 1 and 2 drugs

- currently accepted medical use in the US

- abuse may lead to moderate or low physical dependence or high psychological dependence

Schedule 4 Drugs

• Lower abuse potential than schedule 3 drugs

• Accepted medical uses

• Abuse may lead to limited physical or psychological dependence relative to schedule 3 substances

Schedule 5 Drugs

- Low potential for abuse relative to schedule 4 substances

- Currently accepted medical use in the U.S.

- Abuse may lead to limited physical or psychological dependence relative to schedule 4 substances

Legal regulation of Drugs

- FDA regulates the development and sale

- Local laws further regulate/approves Prescription and OTC

- Nurses must know the laws of the area in which they practice

Federal Food, Drug, and Cosmetic Act of 1938

standards for testing drug toxicity and monitoring labeling

FDA Pregnancy Categories

A= No risk to fetus

B= Little risk to fetus

C= Risk to fetus; must evaluate risks vs benefits

D= Proven risk to humans

X=Risks outweigh benefits

Cells

dynamic factories that

- take in raw materials

- manufacture products to maintain bodily functions

- deliver those manufactured products to the appropriate destination within the body

- differ from one tissue to another

- exchange materials with immediate environment

- obtain energy from nutrients

- reproduce

- communicate with one another via biologic chemicals

T/F: While all cells differ from one tissue to another, they share certain common characteristics.

True

How do drugs transport through the cell membranes?

drugs must reach and interact with cell membrane to affect cellular function

Most drugs are given for...

systemic effect

What moves drug molecules through the body?

transport pathways and mechanisms

Pharmacodynamics

reactions between living systems and drugs/drug actions on target cells and the resulting alterations in cellular biochemical reactions and functions

4 ways drugs work

1. replace or act as substitutes for missing chemicals

2. To increase or stimulate certain cellular activities

3. To depress or slow cellular activities

4. To interfere with the functioning of foreign cells leading to cell death (chemotherapeutic drugs)

Drugs exert their effects by chemically binding with receptor cells through...

- Activation, inactivation, or alteration of intracellular enzymes

- Changes in the permeability of cell membranes to one or more ions

- Modification of the synthesis, release, or inactivation of neurohormones

Receptors

specialized protein structures that are found on cell membranes

Drugs designed to target specific types of receptors to...

initiate, limit, or prevent a biologic response

Response to a drug will depend on...

the affinity or attraction to a receptor and the concentration of the drug already at the receptor site

Drugs are considered ______ or ________ depending on receptor response

agonists or antagonists

Agonists

drugs that produce a response or prolong activity

Antagonists

drugs that block a response

- can be competitive for the receptor site

Nonreceptor drugs

drugs that do not act on receptor sites

What are some examples of nonreceptor drugs?

antacids, osmotic diuretics, several anticancer drugs, and metal chelating agents

Nonspecific drug effect

work on certain receptors but those receptors may be in different organs or tissues. (Ex/cholinergic receptors)

Nonselective drug effect

not selective to just one type of receptor, it can act on different receptors throughout the body.

Pharmacokinetics

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

- specific processes involves

* absorption

* distribution

* metabolism (biotransformation)

+ excretion

Absorption

process that occurs from the time a drug enters the body to the time it enters the blood stream to be circulated to tissues

- Process: Active and Passive transport

Onset of drug action is determined by...

the rate and extent of drug absorption

Factors that affect rate and extent of drug absorption

- dosage, form, route of administration

- administration site blood flow, GI function (gastric pH)

- The presence of food or other drugs

Absorption of enteral medications (meds given through mouth, or any GI tubes) are altered by...

- GI motility

- presence of food in stomach

- pH of stomach

- amount of bowel surface area

- influenced by pain, stress that could divert blood from GI/stomach

Absorption of Parenteral (outside of GI tract)

- Includes routes of administration such as IV, IM, Sub Q

- altered by blood flow to area

- altered by tissue type (fat/muscle)

What is important with Sub Q or IM med injection?

- muscle tissues have more blood vessels, so absorption is faster

- subcutaneous (fatty) tissue has less blood vessels, so absorption is slower

What is not affected by absorption rules?

intravenous administration as the drug immediately enters the circulation via the blood vessel.

Distribution

the transport of drug molecules within the body

Drugs are carried by blood and tissue fluids to...

- Action sites/Metabolism sites/Excretion sites

*Depends on adequacy of blood circulation

Distribution process is affected by?

1. protein binding

2. blood-brain barrier

3. pregnancy

4. lactation

5. drugs lipid solubility

6 drug's ionization

7 perfusion of reactive tissue

Protein binding

drugs attach to protein molecules and travel to site of action (mostly bind to albumin)

- When drug is bound to protein it is inactive unbound drug is free, active drug

- Only unbound drug is able to move through capillaries.

Plasma proteins (mainly albumin) act as carriers for...

drug molecules

Metabolism

the method by which drugs are inactivated or bio transformed by the body

How does metabolism effect drugs?

- can be changed into new, less active chemicals to be excreted

- from active to inactive metabolites then excreted

- inactive prodrugs that become active when metabolized

Drug-metabolizing enzymes are located within...

- kidneys

- liver (most important)

- red blood cells, plasma

- Lungs

- gastrointestinal mucosa

What is the most important site for drug metabolism?

liver

First-pass effect

The initial metabolism in the liver of a drug absorbed from the gastrointestinal tract before the drug reaches systemic circulation through the bloodstream.

enzyme induction

process by which the presence of a chemical that is biotransformed by a particular enzyme system in the liver causes increased activity of that enzyme system

enzyme inhibition

the decrease in hepatic enzyme activity that results in reduced metabolism of drugs

Excretion

elimination of a medication from the body

What organs function during excretion?

- kidneys (most important)

- skin

- saliva

- lungs

- bile

- feces

Factors affecting excretion

- glomerular filtration rate

- urine acidity

T/F: Absorption is the transport of drug molecules within the body.

False

Variables influencing drug therapy

* Clinical factors - age and weight, health disorder, other diseases, client drug compliance

* Administration - Drug form, route of drug administration, multiple drug therapy, drug interactions

* Pharmacokinetics - absorption, distribution, metabolism, excretion

* Pharmacodynamics - Onset, peak, and duration, therapeutic range/window, side effects, adverse reactions.

Onset

time it takes to produce a response

Peak

time to reach highest effect concentration

Trough

Lowest level of concentration reached before next scheduled dose

Duration

Length of time that the concentration is great enough to produce a response

Plateau

maintained level of concentration with repeated fixed doses

Half life

the time it takes for the amount of the drug in the body to decrease in one half (50%) of the peak level it previously achieved

Patient related variables include

Pharmacogenomics,

genetics, ethnicity, sex, pre-existing conditions, psychological factors, tolerance and cross-tolerance

Pharmacogenomics

study of genetic variations in drug responses

Serum drug level

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

what does serum drug level reflect?

-dosage, absorption

-bioavailability, half-life

-rates of metabolism, excretion

What does half-life determine?

appropriate timing and dosing

Factors affecting half-life

- Absorption rate

- Distribution

- Speed of biotransformation

- Rate of excretion

Therapeutic index

the margin between effectiveness and toxicity of a medication

Narrow TI medication

very dangerous r/t the margin of the level of acceptable blood levels is very narrow

What is an example of a narrow TI medication?

digoxin (cardiac glycoside) and inotropic medication that improves the heart muscle contractility in heart failure patients.

- patients taking Digoxin must have their serum blood levels drawn to be sure they are within the acceptable level IE: not subtherapeutic/ therapeutic/ not toxic (TI=0.5-2ng/ml)

____________ must be present for efficacy of serum drug level

minimum effective concentration (MEC)

Toxic concentration

excessive level of medication in the blood stream

What causes toxic concentration?

-single large dose

-repeated small doses

-slow metabolism of medication

Dosage

frequency, size, and number of doses

Route of administration

influences absorption and distribution

Drug-diet interactions

When elements of ingested nutrients interact with a drug and this affects the disposition of the drug

Drug-drug interactions

when the effect of a medication is changed, enhanced, or diminished when taken with another drug, including herbal substances

Interactions that can increase therapeutic or adverse effects include...

- additive effects

- synergism

- interference

- displacement

Interactions in which drug effects are decreased include...

- antidote medication

- decreased intestinal absorption of drugs

- increased metabolism rate of drugs

Adverse effects

any undesired responses to medication administration

- all drugs can produce this.

- can occur with usual therapeutic dosing

- most likely to occur or be more severe with high dosing.

- especially likely to occur with specific drugs and in older adults who take multiple drugs .

Common or serious adverse drug effects

•Central Nervous System

•Gastrointestinal

•Hematologic

•Nephrotoxicity

•Hypersensitivity

•Serum Glucose Levels

drug fever

fever assoc with admin of a drug. Usually because of allergic reaction but can cause by damaging tissues, increasing body heat or interfering with its dissipation or acting on temp regulating center in brain.

Idiosyncrasy

qualitatively abnormal or unusual response