Pharmacology Absorption Concepts

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Questions and Answers

What does the synergistic effect in drug interactions typically indicate?

Two drugs do not interact when taken together.

The combined effect of two drugs is greater than that of either drug alone. (correct)

The combined effect of two drugs is equal to the sum of their individual effects.

The combined effect of two drugs is less than that of either drug alone.

Which of the following describes antagonistic drug effects?

Combination of drugs leads to no observable effect.

Two drugs produce an equal effect to their combined sum.

Two drugs enhance each other's effects.

One drug counteracts the effect of another. (correct)

Which of the following principles is NOT included in the 'Six Rights' of accurate drug administration?

Right drug

Right patient

Right concentration (correct)

Right documentation

What is the role of mucomyst in relation to acetaminophen?

It serves as an antidote for acetaminophen toxicity. Signup and view all the answers

Which of the following combinations exemplifies drug incompatibility?

Heparin with furosemide Signup and view all the answers

What is the purpose of enteric coating on certain drugs?

To dissolve in a high pH environment Signup and view all the answers

Which factor is NOT a contributor to the absorption of oral drugs?

Color of the pill Signup and view all the answers

How does the first pass effect influence drug bioavailability?

It inactivates some of the drug before it reaches systemic circulation Signup and view all the answers

Which of the following drugs would require administration on an empty stomach for optimal absorption?

Micronized glyburide Signup and view all the answers

What is meant by the term 'bioavailability' in pharmacology?

The extent and rate at which the active ingredient is absorbed and becomes available at the site of action Signup and view all the answers

Which condition could lead to decreased absorption of oral drugs?

Sepsis Signup and view all the answers

Why are drugs formulated differently from one another?

To account for differences in absorption and bioavailability. Signup and view all the answers

What role do cytochrome P450 enzymes play in drug metabolism?

They modify a variety of structurally diverse substrates Signup and view all the answers

What does the acronym ADME stand for in pharmacokinetics?

Absorption, Distribution, Metabolism, Excretion Signup and view all the answers

Which factor is NOT mentioned as affecting the absorption of oral drugs?

Condition of the intestines Signup and view all the answers

Which route of administration is likely to provide the fastest absorption?

Intravenous (IV) Signup and view all the answers

Bioavailability is defined as:

The total amount of drug absorbed into the bloodstream Signup and view all the answers

What aspect of drug formulation can influence absorption?

Formulation's water solubility Signup and view all the answers

Which category of pregnancy drugs indicates positive evidence of human fetal risk?

Category D Signup and view all the answers

Which of the following factors would most likely hinder drug absorption?

Administering the drug with food or liquids Signup and view all the answers

What process describes the alteration of a drug within the body?

Metabolism Signup and view all the answers

Study Notes

Enteric Coated Drugs

Enteric coated drugs dissolve in the intestines, specifically at a pH level higher than 7.

Absorption of Oral Drugs

Factors that affect absorption:
- Dosage form and route of administration:
  - Various factors can influence absorption depending on how a drug is administered.
- Status of the absorptive surface:
  - The small intestine's absorptive surface plays a crucial role. If portions are missing or damaged, absorption can be impaired.
- Rate of blood flow to the small intestine:
  - Reduced blood flow to the intestine, as seen in conditions like sepsis, exercise, or labor, can negatively impact absorption.
- Acidity of the stomach:
  - Stomach acidity can influence drug absorption. Food consumption generally increases gastric acid production, reducing stomach pH.
- Status of GI motility:
  - The speed of food and drug transit through the digestive system is crucial. Conditions or medications that alter transit time might affect absorption.
Taking medication with food or fluids:
- Some medications require an empty stomach with a full glass of water for optimal absorption.
- Others benefit from consumption with food to enhance absorption or minimize gastric irritation.
First-Pass Effect:
- Drugs administered orally typically enter the mesenteric blood system and travel to the liver for biotransformation before reaching systemic circulation. This is called the first-pass effect.
- The liver can inactivate a portion of the drug, meaning not all of it reaches its intended action site.
- Drug formulations account for bioavailability, which reflects the amount of drug reaching its target site.
- Different drug formulations might have varying bioavailability.

Cytochrome P450 Enzyme

Many different P450 isoforms exist.
They can modify a wide range of structurally diverse substrates.
One drug might be a substrate for multiple isozymes.

Pregnancy Categories (Pregnancy and Drug Use)

Category C:
- Animal studies have shown adverse effects on the fetus, but no adequate human studies are available.
- Benefits may outweigh risks.
Category D:
- Positive evidence of human fetal risk is available.
Category X:
- Animal or human studies have shown fetal abnormalities or toxicity.
Teratogenic:
- A substance that can cause birth defects.

Pharmacokinetics

Involves drug movement through the body to reach its action site, metabolism, and excretion.
Specific processes include:
- Absorption
- Distribution
- Metabolism
- Excretion

Pharmacologic Principles

Pharmacokinetics (ADME): The science of what happens to a drug from entry into the body until its elimination.
- Absorption:
  - Movement of a drug from its administration site.
- Distribution:
  - Transport of a drug in the bloodstream.
- Metabolism:
  - Alteration of a drug within the body.
- Excretion:
  - Elimination of the drug or its breakdown products from the body.

Absorption

Route of Administration: The route significantly affects the rate and extent of drug absorption.
- Enteral (GI tract):
  - Oral administration
- Parenteral:
  - IV and IM (intravenous and intramuscular) routes
- Topical:
  - Applied to the skin and other locations
Bioavailability:
- The extent of absorption.
- Importantly, not all drug formulations have equivalent bioavailability.

Factors Affecting Oral Drug Absorption

Food or fluids:
- Can either aid or hinder absorption.
- Food might delay transit to the intestines.
- High-fat foods can enhance the absorption of certain fat-soluble drugs.
Dosage formulation:
- Tablets and capsules might dissolve in the stomach or intestines.

Drug Interactions

Synergistic Effect:
- Two drugs combined have a greater effect than either alone.
- Example: HCTZ (hydrochlorothiazide) with enalapril.
Antagonistic Effect:
- Two drugs combined have a lesser effect than either one individually.
- Example: Antacids with tetracycline.
Incompatibility:
- Mixing two drugs causes deterioration of one or both.
- Example: Furosemide and heparin.

Adverse Drug Effects

Drug Dependency:
- When an individual develops a physical or psychological need for a drug.
Idiosyncrasy:
- An abnormal, individual-specific reaction to a drug or food.
Carcinogenicity:
- The ability of a drug to cause cancer.
Teratogenicity:
- The ability of a drug to cause birth defects.

Antidotes for Selected Therapeutic Drugs

Acetaminophen: Mucomyst (N-acetylcysteine)
Digoxin: Digibind (digoxin immune Fab)
Beta Blockers: Glucagon (increases myocardial contractility)
Phenothiazines: Benadryl (diphenhydramine) for extrapyramidal symptoms (EPS)
Coumadin (warfarin): Vitamin K
Heparin: Protamine sulfate
Benzodiazepines: Flumazenil
Cholinergics: Atropine
Calcium Channel Blockers: Calcium gluconate

General Principles of Drug Administration

Six Rights:
- Right patient
- Right drug
- Right dose
- Right route
- Right time
- Right documentation
Other Considerations:
- Proper procedures for preparation and administration must be followed.
- Patients should be monitored for therapeutic outcomes and adverse effects.

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Description

This quiz explores key concepts related to the absorption of oral drugs and the role of enteric coated medications. It covers factors that affect drug absorption, the importance of the intestinal environment, and how different variables impact the effectiveness of drugs. Test your knowledge on these critical pharmacological principles.