Pharmacokinetics Flashcards
What is pharmacokinetics?
What the body does to the drug
What are the origins of some drugs?
Plant
Animal
Mineral
What can drugs be used for?
Treatment
Prevention
Diagnosisi
What are the four pharmachokinetic phases?
Absorption
Distribution
Metabolism
Excretion
What are some of the routes of administration?
Enteral
Parenteral
What are some examples of enteral drugs?
Oral
Sublingual
Rectal
Any drug which goes through the digestive system is enteral
What are some examples of sublingual drugs?
Subcutaneous
Intravenous
Intramuscular
Any drug which avoids the digestive system is sublingual
What are some examples of other drug administration routes?
Topical
Inhalation
Pessary
Transdermal
What does absorption involve?
It is how the drug gets into the blood
It covers the time the blood is administered to the time to drug is available to the tissues for use.
How can drugs be absorbed?
Through passive transport
Through active transport
What is passive transport?
When a drug is lipid soluble and small is can get into the blood quickly and without any need for energy to help the process.
What is active transport?
When a drug is large or polar it is harder for it to get into the blood stream and requires energy to do so. Sometimes carrier proteins are involved in this process.
What factors effect drug absorption?
Drug prep- how the drug is given
Interactions- what the drug interact with such as stomach acid and other foods
Physiological factors- illness or other factors which can effect how fast the drug moves through the digestive system
What does distribution involve?
It is how the drug gets around the body and how fast it does this. It is achieved through the blood stream which transports the drugs
How does blood flow effect distribution?
High/Large blood supply means a high concentration may reach the area
Low/Small blood supply means a lower concentration may reach the area
How does the blood brain barrier affect distribution of drugs?
Drugs which may need to reach the brain are often stopped by the blood brain barrier as it is there to protect the brain and stop toxins and bacteria and often ends up preventing drugs
What effects the availability of drugs when they’re being transported in the blood?
Whether or not they are bound to a plasma protein as that means they will stay in the blood stream and cannot be used. Only free drug is active and can be used
Where does metabolism take place?
The Liver
What is drug metabolism?
Physical and chemical change which can lead to the breakdown of the drug or change into a different substance. It makes drugs inactive so they can go on to be excreted.
What is the first pass effect?
It is the first pass drugs make through the liver. it involves how much of the drug is inactive and how much of the drug will reach the circulation.
It also determines the half-life of the drug and whether bio transformation occurs
What is bio transformation?
It is the conversion of molecules from one form to another . It involves drugs going from inactive to active.
What are drugs that undertake bio-transformation called?
pro-drugs
What is excretion of drugs?
How the body gets rid of the drugs from the body
What are the main organs involved?
Kidneys gut skin lungs salivary glands sweat glands
What is important to consider concerning drug administration in relation to excretions?
Kidney funtion
What is bio availability?
The percentage or fraction of drug that reaches the circulation to then be distributed around the body.
What can affect bio availability?
Route of administration Properties of the drug Absorption Blood flow from administration site First pass effect
What is a therapeutic window?
The window where the drug is effective between being ineffective and causing side effects
How does modified release drugs work?
They slowly release drugs into the GI tract over a period of time
What is drug toxicity?
When a drug has toxic affects on organs.
These drugs are known as latrogenic which is illness caused by medical treatment or examination
What is drug tolerance?
It is the decrease in pharmacological effect a drug has when repeatedly given
What is drug dependency?
When there is a compulsion to take a drug in order to function normally even after it is no longer needed
