Pharmacokinetics 1 Flashcards
studying how the body handles drugs.
What is Pharmacology divided into?
Classically - divided into
Pharmacokinetics and Pharmacodynamics
Summarize the essence of pharmacokinetics.
Pharmacokinetics involves studying the time course of drugs and their metabolites in the body, focusing on what the body does to the drug.
What are the key processes involved in pharmacokinetics?
The key processes in pharmacokinetics include administration, absorption, distribution, metabolism, and excretion.
What does administration refer to in the context of drugs?
Administration is the delivery of a drug to the body.
: Define absorption in relation to drug pharmacology.
Absorption is the movement of a drug across membranes.
How would you describe distribution in the context of drug pharmacokinetics?
Distribution is about how a drug spreads and enters different compartements of the body.
What is metabolism when it comes to drugs?
Metabolism refers to the chemical alteration of a drug.
Explain elimination in the context of drug pharmacokinetics
Elimination is the transfer of the drug from inside the body to the outside.
What does pharmacokinetics help to describe?
pharmacokinetics helps to describe the absorption from the site of administration, delivery to the site of action, elimination from the body, time to onset of effect, duration of effect, accumulation on repeat dosage, and drug interactions.
What are the 7 various surfaces and orifices through which the medical profession can administer medications?
The medical profession can exploit the following surfaces and orifices:
Oral (including buccal and sub-lingual)
Rectal
Skin (topical)
Lungs (including nose)
Eye, Ear
Urethra
Injection (if no convenient orifice is available)
What are the different routes of administration for injections?
Injections can be administered through the following routes:
Intramuscular
Subcutaneous
Intradermal
Intraperitoneal
Intrathecal
Intra-arterial
Why do we give a large dose of Paracetamol (1g) when 90% of it gets metabolized?
We use a large dose of Paracetamol because even though most of it gets broken down in the body, the liver’s ability to process it is limited. Giving a bigger dose ensures there’s enough to provide effective pain relief.
What is the function of the hepatic portal vein (HPV)?
The hepatic portal vein conducts blood from the GI tract to the liver.
Where do drugs administered orally usually pass through before reaching the liver?
Most drugs administered orally pass through the duodenum to the ileum before being transported to the liver by the hepatic portal vein.
What is the significance of the liver in drug administration?
Within the liver, drugs undergo First Pass Metabolism before entering the general circulation.
Define First Pass Metabolism in the context of drug administration.
First Pass Metabolism refers to the metabolic process drugs undergo within the liver before entering the systemic circulation.
Give an example of a drug that is completely metabolized during the first pass.
Glyceryl trinitrate is an example of a drug that undergoes complete metabolism during the first pass and may require alternative routes of administration.
What is a good indicator of how much drug is in the body?
Plasma [drug]
What factors determine the ability of drugs to reach systemic circulation when not administered intravenously?
1) Lipid solubility, 2) Area available for absorption, 3) Possible specific carriers.
What is “first pass” metabolism, and how does it affect the effectiveness of a drug?
“First pass” metabolism is a Biochemical change in the liver.
It Reduce the concentration of the active drug before it reaches the bloodstream.
Result: Compromises the amount of the drug that reaches the target site.
What are the advantages of the oral route of administration?
The oral route is safer and more convenient than injection. Drugs are absorbed through either passive or active transport.
When is the rectal route of administration useful?
The rectal route is useful in patients who are vomiting or unconscious. The rectal wall is well vascularized, allowing for drug absorption.
What is the advantage of buccal, sublingual, or nasal routes of administration?
These routes help avoid presystemic metabolism of drugs.
What is a route of administration that is becoming more popular and helps in avoiding presystemic metabolism?
Transdermal
Which organ provides a large surface for gaseous exchange, making it suitable for the administration of volatile anaesthetics?
Lungs
What is the advantage of administering drugs through the transdermal route?
It avoids presystemic metabolism.