Pharmakokinetics Flashcards
Test I Review
The study of the movement of drugs throughout the body.
Pharmacokinetics
When solid drugs are administered, it is dissolved in ______ before it is absorbed into the blood.
Gastric or intestinal fluid.
True or False?
Administering a fluid with a solid drug speeds up the rate of absorption.
True
The term used to describe the efficiency of absorption into the blood of a particular drug form.
Bioavailability
If two different drug formulations go into the blood with the same efficiency they are said to be?
Bioequivalent
Pharmacokinetics involves four(4)processes :
i. absorption
ii. distribution
iii. metabolism
iv. excretion
Pharmacokinetics involves four processes that determines? (6)
i. serum drug levels
ii. onset of drug action
iii. peak serum level
iv. duration of action of a drug
v. drug half-life
vi. therapeutic and toxic effects of drugs
The process by which a drug passes from its site of administration into fluids of the body that will take it to the site of action
Absorption
The routes mainly used for drug administration.
Oral and parenteral routes
Factor that affect absorption in:
Oral route
i. Presence of food
ii. Food from some food groups
iii. Acidity of stomach
Factor that affect absorption in:
Parenteral routes
i. IV administration
ii. subcutaneous administration
iii. intramuscular
True or False:
In parenterally applied medication, application of heat or massage decreases absorption, while cold packs or compression increase absorption.
False. Heat/massage increase absorption, cold/compression decreases absoprtion.
Injection of ________ at the site of the injection (of the medication) constricts blood flow to the area and thus decreases absorption.
epinephrine
True or False?
Too long needles used for intramuscular drug administration delivers the drug to the subcutaneous tissue not the muscle.
False. Too “short”.
______________ has an unpredictable absorption pattern, so this route is only used when others are not feasible (e.g. in the presence of severe nausea, vomiting) or the drug is require in the lower intestine. To ensure correct absorption, the nurse must check the drug label for correct drug insertion technique.
Rectal administration of drug
Other routes of administration include __(4)__. These routes are useful to protect drugs from chemical decomposition in the stomach and liver.
- Sublingual
- Translingual (on the surface of the tongue) and 3. Buccal and
- Transdermal routes.
Factors that affect Absorption of a drug include: (13)
I. Size of drug molecules II. Physical state III. Properties of the drug IV. Environmental temperature V. State of absorption site VI. Membrane thickness VII. Surface area of body VIII. Blood supply at absorption site IX. Route of administration X. Compliance XI. Presence of food or other drugs in GIT XII. Formulation – enteric, slow release Xlll. Drug forms
True or False?
Liquid drug forms are faster absorbed than capsule and pills.
True
____ alllows absorptions into systemic circulation.
Mucosa
- Involves the transport of drug molecules within the body from the site of absorption to the site of drug action.
- It depends on adequacy of blood circulation: organ with extensive blood supply receives the drug very quickly (e.g., heart, liver, kidney and brain), areas such as muscles, skin and fat receive body supply more slowly.
DISTRIBUTION
Flow of Distribution of the Drug
Drug -> Blood Plasma and/or Tissue fluid -> Site of action of drug
Distribution in the CNS is limited by the?
Blood-Brain-Barrier.
True or False?
Most drug cross the placenta and can affect the foetus.
True
True or False?
Route of administration affects drug distribution.
True
Oral drug go to the liver first and the liver starts breaking down the drug. Hence, less active drug goes into the general circulation for distribution to tissue. This phenomenon is known as the?
“first pass effect.”
Drugs that are highly soluble in fats may accumulate quickly in _____.
Fats
True or False?
Many drugs enter breast milk.
True
Factors that affect distribution: (5)
i. Plasma protein binding
ii. Regional blood flow (vascularity)
iii. Anatomical barrier – blood-brain or blood-placental barrier
iv. Disease
v. Lipid solubility
The _____ route is used to administer certain medications which cannot cross barriers when given intravenously or orally.
- For example, in the administration of gentamicin for meningitis, this antibiotic is administered intrathecally because it cannot cross the blood-brain- barrier when given by IV route.
The intrathecal route.
_____ drugs form a complex with plasma protein, particularly albumin.
Lipid drugs
Drugs bound to protein are _______; they do not leave the blood stream.
Pharmacologically inactive