Pharmacology Long Exam Reviewer

Pharmacology

Pharmaco (drugs); ology (study) Study of drugs

Pharmacology

Study of substances that interact with living systems through chemical processes, especially by binding to regulatory molecules and activating or inhibiting normal body processes

Drug

Substance that alter physiologic function in the organism, regardless if beneficial or harmful

Toxicology

Study of harmful effects of chemicals

Toxicology

Deals with undesirable effect chemicals on living systems, from individual cells to complex ecosystems

Medical Pharmacology

Science of substances used to prevent, diagnose, and treat diseases

Pharmacotherapeutics

Use of specific drugs to prevent, treat, or diagnose disease

Pharmacokinetics

Study of how the body deals with the drug in terms of the way the drug is absorbed, distributed, and eliminated in our body

Pharmacodynamics

Analysis of what the drug does to our body, including the mechanism by which the drug exerts its effect

Mechanism of action of the drug

Pharmacy

Deals with the preparation and dispensing of medications

17th Century

Reliance on observation and experimentation replaced theorizing in medicine

Materia Medica

Science of drug preparation and the medical use of drugs began to develop as the precursor to pharmacology

Late 18th and 19th Century

Francois Magendie and later his student Claude Bernard began to develop methods of experimental physiology and pharmacology

18th, 19th, and Early 20th Century

Advances in chemistry and further development of physiology laid the foundation needed for understanding how drugs work at the organ and tissue levels

50 Years Ago

Concept of rational therapeutics - controlled clinical trial were introduced, if not approved, drugs should not be released to the public

Last Half of the Century

Many fundamentally new drug groups and new members of old groups were introduced

Last 3 Decades

More rapid growth in understanding the molecular basis for drug action

Pharmacogenomics/Pharmacogenetics

Study of the genetic variations that cause differences in drug response among individual or populations

Chemical Name

Refers to the specific structure of the compound and is usually fairly long and cumbersome

Generic Name

Often derived from the chemical name

Official or Non-proprietary

Trade Name

Assigned to the compound by the pharmaceutical company and may or may not bear any reference at all to the chemical and generic terminology

Propriety or Brand

Pre Clinical testing

Initial laboratory tests to determine drug effects and safety

Subjects are laboraty animals

usually 1-2 yrs

Human (clinical) Testing/Phase I

Determine effects, safe dosage, pharmacokinetics

Small number of < 100 (healthy) volunteers

Phase II

Assess drug’s effectiveness in treating a specific disease/disorder

Limited number of 200-300 pt.s with target disorder

2 yrs

Phase III

Assess safety and effectiveness in larger patient population

Large number of 1000-3000 patients targeted

3 yrs

Phase IV

Monitor any problems after NDA approval

General patient population

Indefinite

Thalidomide

Magic Drug

Treatment for threatened abortion

Phocomelia

a rare condition that affects babies at birth that causes the UE or LE to be underdeveloped or missing

8 years

time it takes for a drug to get NDA approved

Other vaccines/Normal Drugs

Drugs that are not considered as “for emergency use”

Orphan Drugs

Drugs that treat rare diseases

May be indicated for only the relatively small population with the disease that is fewer than 200,000 people in the United States

Orphan Drugs

It is used to treat rare diseases

More expensive

Longer processes as the subjects are limited

The researchers who developed these kinds of drugs are also few because the market is also limited

Off-Label Prescribing

It is the use of a drug to treat conditions other than those that the drug was originally approved to treat

OTC Medications

Used to treat relatively minor problems and to make the consumer more comfortable until the condition is resolved

Judged to be safe for use by the consumer without direct medical supervision

OTC Medications

Chances of toxic effects are usually small when the medications are taken in the recommended amounts

have a much lower pharmacologic impacts than their prescription counterparts

OTC Medications

Does not require prescription from doctors or dentists

Prescription Medication

May be ordered or dispensed only by an authorized practitioner (i.e. Physician or Dentist)

Requires prescription

Header

Physician’s name

Clinic

Contact number

Clinic schedule

Affiliated hospital (sometimes included)

Patient’s Data

Name

Age

Address

Sex

Date of Consultation

Symbol

Rx- “recipere” in latin, “recipe” in english

Number Sign

It will tell you how many capsules or bottles you need to buy

Special instruction

How to prepare the drug

Sig or Signetur (Latin)

Instruction on how to take the medicine

Professional Tax Receipt (PTR)

A license that physician’s usually get, review, and pay every year

In the Philippines, this is in the benefit of senior citizens who are asking for a prescription for them to be able to enjoy their 20% discount. Drug stores usually look for this

Yellow Prescription

Other name for prescribing Controlled Substances

Anesthesiologists

Can also give special prescriptions

Schedule I

group of drugs with the highest potential for abuse. Legal use of these agents is restricted to approved research studies or therapeutic use in a very limited number of patients

Schedule I

Heroin, LSD, Tetrahydrocannabinois

Schedule II

drugs that are approved for specific therapeutic purposes but still have a high potential for abuse and possible addiction. We use these medically, it is prescribed to patients. These drugs belong to the Opioid group.

Schedule II

Morphine, Phenobarbital

Schedule III

these drugs have a lower abuse potential than S.1 and S.2 but there is still the possibility of developing mild to moderate physical dependence or strong psychological dependence or both

Schedule III

Opioids such as Codeine and Hydrocodone.

Schedule IV

these drugs supposedly have a lower potential for abuse than S.3 drugs, with only a limited possibility of physical dependence, psychologic dependence, or both.

Schedule IV

Diazepam, Chlordizepoxide

Schedule V

\- type of drugs that have the lowest relative abuse potential. Drugs in this category consist primarily of low doses of Opioids that are used in cough medications and antidiarrheal preparation.

Teratogenic

agents/substances are extremely dangerous during prenatal development

Category A

controlled studies in women fail to demonstrate a risk to the fetus in the first trimester Page 1 of 9 (and there is no evidence of a risk in late trimesters), and the possibility of fetal harm appears remote.

Category B

either animal production studies have not demonstrated a fetal risk, but there are no controlled studies in pregnant women, or animal reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the first trimester (and there is no evidence of risk in later trimesters).

Category C

either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal or other) and there are no controlled studies in women, or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus

Category D

There is positive evidence of human fetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drugs are needed in a life threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective)

Category X

studies in animals or human beings have demonstrated fetal abnormalities or there is evidence of fetal risk based on human experience or both. The risk of the use of the drugs in pregnant women clearly outweighs any possible benefit. The drug is contraindicated in women who are or may become pregnant.

Threshold Dosage

Starting Dose

Maximal Efficacy

Highest or peak effect of drug

Plateau

indicates that there will be no further increment in the response even if the dosage continues to be increased

Ceiling Effect

Maximal Dose (just like plateau)

Potency

related to the dosage that produces a given response in a specific amplitude. It refers to the fact that less of the compound is required to produce a given response.

Quantal Dose Response Curve

percentage of the population who exhibit a specific response as the dose is increased

Median Effective Dose (ED 50)

dose at which 50% of the population respond to the drug in a specified manner

Median Toxic Dose (TD 50)

dosage at which 50% of the group exhibits the adverse effect

Median Lethal Dose (LD 50)

dose that causes death in 50% of the animals studied

we do not do this in humans

Therapeutic Index

used as an indicator of the drug’s safety; relates the dose of a drug required to produce a desired effect to that which produces an undesired effect

Alimentary/Enteral

oral, rectal

Non-alimentary/Parenteral

inhalation, injections, topical, transdermal

Injection

Insulin

First-Pass Effect

after absorption from the alimentary canal, the drug is transported directly to the liver via the portal vein, where a significant amount of the drug may be metabolized and destroyed prior to reaching its site of action

Iontophoresis

an electric current “drives” the ionized form of the medication through the skin

Phonophoresis

also known as sonophoresis

uses ultrasound waves to enhance transmission of medication through dermis

Intravenous

antibiotics

(variant of injection)

Intra-arterial

difficult and dangerous procedure E.g., contrast during diagnostic tests

(variant of injection)

Intramuscular

useful for treating problem located directly in the injected muscle

E.g., vaccines, antibiotics

(variant of injection)

Subcutaneous

injected directly beneath the skin

E.g., insulin, diabetic medicines

(variant of injection)

Intrathecal

deliver medication within a sheath

E.g., anesthesia, spinal block

(variant of injection)

Bioavailability

a parameter expressed as the percentage of drug that reaches your bloodstream

depends on the route of administration and drug’s availbility to cross membrane barriers

defined as the fraction of unchanged drug reaching the systemic circulation following route administration

Lipids

actually phospholipids that acts as a water barrier

Protein

interspersed throughout the lipid bilayer which exist primarily in the outer or inner portion of membrane

Passive Diffusion

movement occurs without any energy being expended (No ATP)

Rate of Diffusion

Depends on the ff:

a. Magnitude of the concentration difference

○ ↑ concentration difference = faster diffusion

b. The size of the diffusion substance

○ smaller=faster diffusion

c. The distance over which diffusion occurs

○ shorter distance=faster diffusion

d. The temperature

○ ↑temp= faster diffusion

Effect of Ionization on Lipid Diffusion

drug will diffuse more rapidly thru the lipid layer if they are in neutral and ionized form

most drugs are weak acids or weak bases but have a potential to be charged depending on body fluids

Diffusion Trapping

changes in lipid solubility caused by ionization can also be important when the body attempt to excrete a drug in the urine

Diffusion between Cell Junction

drug may diffuse across the barrier by diffusing first into and then out of the other side of the cells comprising the barrier

Osmosis

refer to special case of diffusion

diffusing substance is water

certain drugs may diffused thru the process of “ bulk flow”

Active Transport

also called “carrier-mediated transport”

membrane proteins shuttle substances from one side to the other side

Facilitated Diffusion

presence of protein carrier but no net energy expended

inability to transport substances “uphill

Endocytosis

drug is engulfed by the cell via invagination of the cell membrane

Exocytosis

substances synthesized within the cell can be encapsulated in vesicles, merged with the inner surface of membrane, and extruded thru membrane and out of cell

Tissue Permeability

A highly lipid soluble drug can potentially reach all the different body compartments and enter every cell it reaches

Tissue Permeability

The blood-brain barrier limits the movement of drugs out of the bloodstream and into the CNS tissue

Blood Flow

Drugs will gain greater access to tissues that are highly perfused

Binding to Plasma Proteins

Certain drugs will form reversible bonds to circulating proteins in the bloodstream such as albumin

Binding to Plasma Proteins

Only the unbound or “free” drug is able to reach the target tissue and exert the pharmacologic effect

Binding to Subcellular Components

Drugs bound to specific cells are unable to leave the cell and be distributed through other fluid components