1 Pharmacokinetics Flashcards
What is the first pass effect?
After the drug is absorbed in the gastrointestinal track, it is transported directly into the liver, via portal vein, where a large amount of the drug may destroyed prior to reaching its site of action.
What are the advantages of oral administration?
- Easiest way to take medications.
- Self-administration.
- Drugs enter system in a controlled manner.
- Absorbed in small intestine.
What are the disadvantages of oral administration?
• Drugs must have a high degree of lipid solubility to pass through mucosa into bloodstream.
• Nonlipid-soluble drugs are poorly absorbed.
• Drugs may irritate the stomach.
• Acidic environment may cause the drug to be destroyed prior to absorption.
• The amount and rate at which the
drug reaches the bloodstream is unpredictable .
What are the benefits of sublingual and buccal administration of a drug?
- Absorbed through oral mucosa into the venous system.
- Venous system returns blood to heart.
- Drug can reach the circulation w/o first- pass.
- Good for pts who can not swallow.
What are the disadvantages of sublingual and buccal administration of a drug?
- Amount of drug given is limited.
* Drug must be able to pass through oral mucosa.
What are the benefits of rectal administration of a drug?
• Drug can be given to an
unconscious pt.
• When vomiting prevents drug from being given orally.
What are the disadvantages of rectal administration of a drug?
- Drugs are absorbed poorly, or incompletely.
* Irritation of the rectal mucosa.
True or false: paraenteral drugs are not subjected to first pass
True
In which forms can an inhaled medication be taken?
Drugs that exist in a gaseous state, or that can be suspended as tiny droplets in an aerosol form, can be inhaled.
What are the benefits of inhalation for drug administration?
• Large surface are
for diffusion of drug into circulation.
• Rapid entry of drug into blood stream.
• Administer anesthesia.
• Applies medication directly to lungs.
What are the disadvantages of inhalation for administration of a drug?
• May irritate respiratory tract. • Trouble with self- administration. • Drug particles trapped in cilia and mucus. • Hard to predict quantity of drug that reaches lungs.
Where are IVs injected?
Peripheral vein
What are the benefits of intravenous drug administration?
- Known quantity of drug into blood stream over short period of time.
- Peak levels of drug instantaneously.
- Immediate drug effect.
- Can give over long period.
What are the disadvantages of using intravenous drug administration?
- sudden onset of large quantities of drugs in plasma
- adverse reactions
- human error
- trouble with self administration
What are the advantages of inter-arterial drug administration?
- Focused administration of drugs
- Avoids drug to healthy tissue
- Immediate drug effect.
- Can use for dx procedures.
What are the disadvantages of inter-arterial drug administration?
- Sudden onset of a large dose of drugs in specific site.
- Adverse reactions
- Human error
- Difficult and dangerous procedure
When would one use subcutaneous administration of a drug?
When a local response is needed
What are the benefits of subcutaneous injection as a means to administer a drug?
- Easy to perform
- Patients canperform on self
- Slower prolonged release of drug
- Can be used for implantable preparations
What are the disadvantages of subcutaneous administration of a drug?
- only small amounts given
- drugs can irritate subcutaneous tissue
What are the benefits of intramuscular injections of drugs?
- Easy access to site
- Treat problems directly at site
- Steady prolonged release of drug
- Rapid effect of drug
- No increase in plasma levels site
What are the disadvantages of intramuscular drug administration?
- Localized pain at site
- drug can irritate muscle tissue
Where are intrathecal drugs administered?
Subarachnoid space
What are the benefits of intrathecal administration?
- No increase in plasma levels
- Used for narcotic analgesics, anesthetics
- Drugs bypass blood-brain barrier
What are the disadvantages of intrathecal administration of a drug?
- hard to administer
- can irritate spinal tissue
