Lecture 2: Basic Principles of Pharmacology II Flashcards
What forms of drugs can easily diffuse?
Nonionized forms
What forms of drugs do not diffuse?
Ionized forms
What are the 2 types of routes of administration?
- Enteral (Oral, Rectal, Sublingual)
2. Parenteral (Intravenous, Intraarterial, Intramuscular, Subcutaneous, Intrathecal, Topical, Inhalation)
What are some of the advantages of oral administration?
Easy, safe, prolonged absorption causing prolonged effect
What are some of the disadvantages of oral administration?
- Absorption may be too slow
- Absorption variable and unpredictable
- Drugs can be completely metabolized on first pass through liver
- Not available for comatose, vomiting patients.
What are some advantages of rectal administration?
- Useful for infants, comatose, vomiting pts
- Useful for foul-smelling, distasteful drugs
- Useful for drugs destroyed in upper gastrointestinal tract
- Avoids immediate metabolism liver
What are some of the disadvantages of rectal administration?
- Nuisance - poor compliance
- Absorption may be erratic, incomplete
- Rectal irritation
What are some of the advantages of sublingual administration?
- By-basses liver when first absorbed
2. Rapid absorption
What are some of the disadvantages of sublingual administration?
- Must be soluble in saliva, have appropriate pKa rapid absorption
- Tablets must be small
Advantages of intravenous administration?
- Rapid effect
- Can watch response and titrate dose
- For drugs given in large volumes of fluid and continuous monitoring
What are some of the disadvantages of intravenous administration?
- Cost
- Danger of infection
- Possible anaphylactic rxn
- Danger of embolus formation due to air, drug precipitation, RBC agglutination
- Danger of adverse cardiovascular effects if administration too rapid
Advantages of intraarterial route?
- Administration of radioopaque material for visualization of circulatory tree
- High conc. of drug going to local when desirable
Disadvantages of the intraarterial administration?
As for iv administration
What are some of the advantages of intramuscular?
- When oral route is not available
- Absorption less variable than with oral route
- Absorption more rapid with s.c. route
- Possibility of slowing absorption to prolong effect
Disadvantages of intramuscular route?
- Possible local necrosis
- Accidental i.v. injection possible
- Should not be used after anticoagulant administration
Advantages of subcutaneous route?
- Absorption usually slower than after i.m., and effect more prolonged
Disadvantages of subcutaneous route?
As for i.m. administration
Advantages of intrathecal?
When local effect on CNS required other route unsatisfactory
Disadvantages of intrathecal?
- Skill
2. Danger of spinal cord injury
Advantages of topical?
- for local action on or under skin
2. non-invasive
Disadvantages of topical route?
- Difficulty of absorption through skin
2. Danger of excessive absorption through membranes and systemic toxicity
Advantages of inhalation route?
- Rapid absorption for systemic action
- High conc. attainable for local effect
- Self administration possible