How Drugs Work Flashcards
Dosage Form
The means by which a drug is avaliable for use. This form is mostly chosen by which method will be the most effective. There are 3 types of ways drugs get into our body: Enternal (GI tract), Parenteral (Injected into tissues), and Topical (applied to skin or mucous membrane)
Receptor
The cellular material directly involved in the action of the drug. (lock) They are located on the surfaces of the cell membrane and inside cells. Most receptors are found throughout the body, although some occur in only a few places.
Drug Molecule
The key
Site of action
The place where the drug causes an effect to occur
Drugs are ____
Selective. Meaning that its action is specific to certain receptors and tissues they affect.
How drugs Interact with site of action
Act through physical action
React Chemically (antacids)
Modify the metabolic activity of pathogens (antibiotics)
Change the osmolarity of blood and draw water out of the tissue and into the blood (diuretics)
Join with other chemicals to form a complex that is more easily excreted
Modify the biochemical or metabolic process of the body’s cells or enzyme systems
Agonists
Activate receptors to accelerate or slow normal cellular function
Antagonists
Binds with receptor to block action at receptor site.
Extended stimulation of cells with an antagonist can cause…..
an increase to the number of the sensitivity receptors.
Extended stimulation of cells with an agonist can cause…..
a reduction of the number or sensitivity of the receptor.
Pharmacokinetics
Encompasses the many different components of the actions of the body on a drug.
Levels of the drug throughout the blood and tissues
Absorption of the drug throughout the body
Overall distribution
The reaction of the drugs with other drugs
Patient compliance
Life of the drug (bioavailability, half-life, bioequivalence, and elimination)
Pharmacodynamics
The effects of the drug on the body.
Absorption
Medications are made to get through natural body barriers, such as skin, stomach, instestines, blood-brain barrier, and other membranous tissues. The absorption is a factor that determines a drug’s effectiveness.
Distribution
After a medication is absorbed, it is distibuted throughtout the body via the bloodstream into tissues, membranes, and ultimately organs. Distribution may not be equal throughout the body. Most drugs bind to blood proteins to some degree.
Metabolism
Takes place in the liver, changes the chemical structure of the original drug. Different factors contribute to metabolism (age, gender, genetics, diet, and other chemicals ingested)
First-Pass Effect
For some drugs, the dose travels to the liver, and part of it is metabolized before the drug has a chance to be distributed throughout the body
This first-pass effect lowers a drug’s bioavailability
First-pass drugs are given in larger doses
Elimination
Last phase of a drug’s life in the body.
Can be excreted in many ways (kidneys, feces, exhalation, sweat glands, and breats milk)
Urination and bowel movements are the most common.
Bioavaliability
The rate at which a drug makes it to its destination and becomes available to the site of action for which it is intended. Different drugs clear in different ways and a different times.
Half-life
The amount of time it takes the body to break down and excrete 1/2 of the drug. An important factor in the creation of drugs bc it tells the manufacturer how long it takes the body to get rid of the drug
Bioequivalence
The comparison between drugs either from different manufacturers or in the same company but from different batches of a drug. Generic drug manufacturers strive to achieve bioequivalence to compete with brand name manufacturers.
Excipients
All medications are prepared with additives (coloring, flavoring, fillings, and preservatives). Some patients may be allergic or intolerant to these. Other types of excipients: Increase the dispersion of a drug once it reaches the intestines, or release the medication over a longer period
Packing and storage requirements
All dosage forms must be approved by the FDA. They are packed according to the manufacturer’s specifications to ensure the effectiveness and shelf life of the drug. All meds have a package insert that describes the storage and stability of the drug.
Classification of meds
Can be based on: Pharmacology Intent of use Route of administration Mechanism of action Body System affected
