Pharmacokinetics Flashcards
Difference between PK and PD?
PK: what the body does to a drug
PD: what the drug does to the body
Components of PK
Absorption
Distribution
Metabolism
Excretion
What happens in passive distribution?
Movement of drugs from area of high concentration to low concentration
What happens in active transport?
Drugs are moved across the gut wall via transporter proteins - requires energy
Drug absorption pathway when given orally vs IV
Oral –> stomach –> small intestine –> hepatic portal vein –> liver –> systemic circulation
IV –> systemic circulation
Disintegration vs dissolution
During which is the active ingredient released?
Disintegration - when a drug is broken into smaller pieces
Dissolution - when a drug dissolves; this is when active ingredient is released
Dosage forms fastest to slowest rate of absorption
IV SL ODT IR tablet ER tablet
What is a “micronized” medication? What is the benefit?
Drug with very small particle diameters
Increased dissolution rates over other oral formulations of the same drug
What is bioavailability?
The extent to which a drug is absorbed into the systemic circulation
What is considered a high bioavailability?
70% or higher
What is considered a low bioavailability?
10% or lower
Bioavailability calculation
100 x (AUC extravascular/AUC intravenous) x (Dose intravenous/Dosse extravascular)
What is drug distribution?
The process by which drug molecules move from systemic circulation to the various tissues and organs of the body
What factors favor greater drug distribution?
High lipophilicity
Low molecular weight
Unionized status
Low protein binding
If a medication is highly protein bound, what will make it’s distribution higher?
Low albumin (higher percentage of drug will be unbound from albumin and able to move extravascularly)
