Pharmacotherapy Flashcards
What is Pharmacokinetics?
“what the drug does to the body”, describes a drug’s pathway into, through and out of the body
What are the four phases of pharmacokinetics?
Absorption, Distribution, Metabolism and Excretion (ADME)
What could Pharmacokinetics help with?
Define onset, duration and intensity of a drugs effect (which could be impacted by patient related factors and drug properties)
What factors influence drug response?
-physiologic: age, sex, weight
-pathophysiologic: kidney and liver function
-Genetic variability: lack of certain enzymes
-drug interaction
What are the three ways for a drug to cross a cell membrane?
- direct penetration of cell membrane
-channel and pores
-transport systems
Factors affecting drug absorption:
-rate of dissolution
- surface area
- blood flow
- lipid solubility
- pH
What is the bioavailability of IV drugs?
100%
What is bioavailbility?
its amount of drug absorbed / drug dose
What is bioavailability affected by?
Gastric Emptying time, the pH of the Stomach, The speed of the drugs moves through the GI tract
What is Bioequivalence?
2 different drugs products or dosage forms of the same drug produce the same concentration vs. time curves (important for generic products)
What is the First Pass Effect?
The First Pass Effect is when drugs taken orally travel from the GI tract to the liver through the hepatic portal circulation. In the liver, they can be metabolized or inactivated before entering the bloodstream, which can reduce their therapeutic effects. To avoid this, drugs can be administered through other routes like parenteral, sublingual, or transdermal. An example is nitroglycerin.
What are the characteristics, advantages, and disadvantages of the Intravenous (IV) route of drug administration?
Characteristics:
No barriers to absorption, leading to instant and complete drug delivery.
Advantages:
Rapid onset of action.
Precise control over drug administration.
Suitable for dissolving drugs in large fluid volumes.
Allows safe administration of irritant drugs through high-flow veins.
Disadvantages:
High cost and inconvenience.
Safety issues associated with IV administration.
Irreversibility once administered.
Risk of fluid overload.
Potential for infection at the injection site.
Possibility of embolism when not properly administered.
What are the characteristics, advantages, and disadvantages of Intramuscular (IM) and Subcutaneous (SC) routes of drug administration?
Characteristics:
No significant barriers to absorption as drugs can pass freely through the capillary wall.
Absorption pattern depends on drug solubility in water and blood flow.
Advantages:
Suitable for poorly soluble drugs.
Can be used for depot preparations, allowing slow, sustained release of medication.
Disadvantages:
Discomfort and potential pain associated with injection.
Inconvenience compared to oral administration.
What are the characteristics, of the oral route of drug administration, including different dosage forms?
Characteristics:
Barriers to absorption: epithelial cells lining GI tract, capillary wall (most drugs pass freely).
Absorption pattern influenced by: drug solubility and stability, gastric and intestinal pH, gastric emptying, presence of food, co-administration of other drugs, and dosage form (e.g., enteric coating).
Dosage Forms:
Liquids: suspensions, emulsions, elixirs, solutions.
Capsules: hard (can be opened, immediate or controlled release), soft (generally cannot be opened).
Tablets/Caplets: various types (immediate release, enteric coated, extended release, etc.), caution with extended release forms (cannot be crushed, if scored can be halved). Check drug monographs for specific instructions.
What are the advantages, and disadvantages of the oral route?
Advantages:
Easy and convenient administration.
Available in many dosage forms.
Inexpensive compared to other routes.
Generally considered safe.
Disadvantages:
Variability in absorption.
Potential inactivation of the drug during digestion.
Specific patient requirements (e.g., ability to swallow).
Possible local irritation.
