Pharmacology Chapter on Drug Problems

Questions and Answers

What does the term pharmacokinetics refer to?

The effects of drugs on the patient.

The movement of medicine through the body. (correct)

The chemical properties of drugs.

The study of drug interactions and side effects.

Which of the following is NOT part of the pharmacokinetic process?

Absorption

Metabolism

Concentration (correct)

Distribution

What does pharmacodynamics primarily focus on?

The chemical composition of drugs.

The movement of drugs in the body.

The routes of drug administration.

The effects produced by administered drugs. (correct)

Which route of drug administration is mentioned as the most common?

Oral Signup and view all the answers

What is one of the main treatment modalities mentioned for the problems of excess output in infants?

IV fluid containing glucose Signup and view all the answers

Which of the following best describes the undesirable effects of medication?

Unwanted side effects Signup and view all the answers

What is the impact of metabolism within the pharmacokinetic process?

It converts drugs into an inactive form. Signup and view all the answers

What does the 'E' in ADME stand for?

Elimination Signup and view all the answers

Which of the following factors is NOT related to drug absorption?

Drug expiration date Signup and view all the answers

Why are drugs generally absorbed more effectively in the small intestine than in the stomach?

Presence of villi in the small intestine Signup and view all the answers

How does food intake generally affect drug absorption?

Can either enhance or reduce absorption Signup and view all the answers

What is bioavailability mainly defined as?

Quantity of drug absorbed relative to administered amount Signup and view all the answers

Which of the following drugs may be better absorbed when taken with fatty food?

Accutane Signup and view all the answers

What is the effect of a fatty meal on gastric emptying?

Slows down gastric emptying Signup and view all the answers

Which statement accurately describes drug absorption via intravenous administration?

It results in rapid and almost complete absorption Signup and view all the answers

What role does lipid-water solubility play in drug absorption?

Affects the ability of a drug to cross cell membranes Signup and view all the answers

Where is most drug absorption likely to occur when a drug is administered orally?

Small intestine Signup and view all the answers

What characteristic of weakly acidic drugs aids in their absorption in the stomach?

They are more readily absorbed in acidic mediums. Signup and view all the answers

Which factor does NOT affect oral drug absorption?

Time taken to swallow the drug Signup and view all the answers

What happens to peptide drugs such as insulin when taken orally?

They do not survive gastrointestinal enzymes and are poorly absorbed. Signup and view all the answers

Why does the small intestine allow for increased drug absorption compared to the stomach?

It possesses villi that increase the surface area. Signup and view all the answers

What is a likely outcome for weakly basic drugs when absorbed?

They are more readily absorbed in the small intestine. Signup and view all the answers

Which of the following statements about gastrointestinal absorption is true?

The luminal pH varies along the GI tract and affects drug absorption. Signup and view all the answers

What is a significant barrier for drug absorption in the stomach?

Thick mucous layer. Signup and view all the answers

What happens to the plasma drug concentration when a larger average volume concentration (AVC) is administered to Patient A?

Plasma drug concentration increases. Signup and view all the answers

Which statement is true regarding T max following intravenous bolus administration?

T max is shorter with higher AVC. Signup and view all the answers

What aspect of drug administration is absent when drugs are given via intravenous bolus?

Drug absorption. Signup and view all the answers

How is drug administration via intravenous bolus often compared to other methods?

It is like administering a drug in a bag, slowly. Signup and view all the answers

What occurs immediately after administering a drug intravenously?

The entire dose enters the bloodstream. Signup and view all the answers

What is one effect of having a smaller Area under the curve (Arc)?

Decreased drug concentration over time. Signup and view all the answers

Faster elimination of a drug typically correlates with which outcome?

Lower concentration at T max. Signup and view all the answers

Following intravenous administration, what does the graph generally depict in terms of plasma drug concentration over time?

Immediate peak followed by a decline. Signup and view all the answers

What type of drug is less likely to be administered orally due to its difficulty in crossing membranes?

Hydrophilic drugs Signup and view all the answers

Which of the following factors does NOT affect oral drug absorption?

Skin permeability Signup and view all the answers

When might a weak acid drug be most effectively absorbed in the body?

When in a highly acidic environment Signup and view all the answers

What happens to a weak base drug when placed in the stomach?

It remains fully ionized and poorly absorbs Signup and view all the answers

The pKa of a drug is crucial because it determines the ratio of which types of forms?

Ionized and non-ionized forms Signup and view all the answers

Under which condition does a weak acid primarily exist in its un-ionized form?

When the pH is lower than the pKa Signup and view all the answers

Which characteristic aids in the absorption of drugs across the phospholipid bilayer?

Lipid solubility Signup and view all the answers

What is the result of a drug's ionization status on its oral absorption?

Decreased ionization enhances absorption Signup and view all the answers

Study Notes

Pharmacology Overview

Pharmacokinetics studies how drugs move through the body, involving absorption, distribution, metabolism, and excretion (ADME).
Pharmacodynamics refers to the effects produced by drugs, differentiating it from pharmacokinetics.

Drug Administration

The most common drug administration route is oral, although topical routes are also utilized.
Routes and methods significantly influence drug absorption and bioavailability.

Drug Absorption Factors

Drug-related Factors: Includes drug formulation, molecular size, lipid solubility, and ionization status.
Individual-related Factors: Encompasses absorptive surface area, pH of the gastrointestinal tract, and food intake.

Absorption Mechanisms

Oral drugs must withstand low pH and gastrointestinal secretions to be absorbed effectively.
Absorption is primarily through the small intestine due to a larger surface area facilitated by villi, compared to the stomach.

Influence of pH on Drug Absorption

Weakly acidic drugs are better absorbed in acidic conditions (stomach), while weakly basic drugs absorb better in more alkaline conditions (small intestine).
Ionization status is influenced by the pH relative to the drug's pKa; un-ionized drugs are more easily absorbed.

Bioavailability Insights

Bioavailability measures the fraction of the drug that reaches systemic circulation unchanged.
Intravenous (IV) administration has nearly 100% bioavailability, unlike other routes where absorption is incomplete.

Food Interactions

Food can slow gastric emptying and alter absorption rates; some drugs are better absorbed on an empty stomach while others may benefit from food, particularly fatty foods.

Drug Excretion and Elimination

After IV administration, drugs do not experience an absorption phase, as the entire dose enters circulation directly.
Factors such as surface area and gastrointestinal blood flow affect the extent of drug absorption and subsequent therapeutic effects.

Key Points on Drug Forms

Acidic drugs remain un-ionized in the stomach, facilitating absorption, while basic drugs tend to be ionized.
The ionization level influences lipid solubility and the ability of the drug to cross cell membranes.

Pharmacokinetic Parameters

Plasma concentration over time shows that rapid absorption leads to a shorter time to reach maximum concentration (T max) compared to slower absorption profiles.
The pharmacokinetic profile guides dosage and administration strategies for effective treatment.

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Description

Explore the challenges faced in pharmacology, focusing on drug issues related to excess output in infants and reduced input in adults. Understand how IV fluids containing glucose can be crucial in treatment. This quiz covers key pharmacokinetic principles and their applications.