Pharmacokinetics I: Drug Administration and Absorption

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Questions and Answers

What is a primary benefit of encapsulation techniques for drug administration?

They allow oral administration of drugs that were previously limited to parenteral routes. (correct)

They ensure faster drug absorption compared to injection.

They eliminate the first-pass effect encountered with oral medications.

They completely prevent degradation of drugs by gastric proteases.

Which of the following is a key drawback associated with oral drug administration?

The potential for drug degradation due to stomach acidity and digestive enzymes. (correct)

The controlled and predictable absorption into the bloodstream.

There is minimal to no impact of the first-pass effect on the drug.

Drugs bypass the liver, leading to increased drug concentration.

What is the 'first-pass effect' in the context of oral drug administration?

The initial rate of drug absorption in the intestines.

The degradation of the drug in the bloodstream after absorption.

The direct transport of the drug to the heart via the superior vena cava.

The metabolism of the drug in the liver following absorption from the GI tract, before it reaches its target site. (correct)

Why is absorption of orally administered drugs considered unpredictable compared to direct routes of administration like injection?

Absorption is influenced by factors such as intestinal infection, food presence, gastric emptying rate, and blood flow in the viscera. Signup and view all the answers

How does sublingual and buccal administration differ from oral administration?

They both utilize the oral mucosa for absorption from areas draining into the superior vena cava, bypassing initial liver metabolism. Signup and view all the answers

What is a primary limitation of rectal drug administration?

Poor or incomplete drug absorption. Signup and view all the answers

Which of these is a main disadvantage of the parenteral route of drug administration??

The potential for infections if sterility is not maintained. Signup and view all the answers

What characteristic of IV bolus injection results in a rapid peak drug level in the bloodstream?

Immediate introduction of a known drug quantity to the bloodstream. Signup and view all the answers

What is the primary reason why rectal administration is advantageous in specific situations?

It is suitable for administering drugs to unconscious individuals. Signup and view all the answers

Which route of administration is NOT categorized as parenteral?

Oral administration. Signup and view all the answers

What is the main focus of using inhaled drugs as mentioned in the text?

To improve drug delivery through the oral mucosa. Signup and view all the answers

What is a disadvantage linked to all forms of injection?

The risk of infection if sterility is not ensured Signup and view all the answers

What distinguishes parenteral drug administration from other methods?

It directly delivers drugs to the target site. Signup and view all the answers

What is the primary focus of pharmacokinetics?

The analysis of how the body processes and removes pharmacological substances. Signup and view all the answers

Which factor is NOT explicitly mentioned as a consideration when maximizing a drug’s ability to reach target tissues?

The drug’s binding affinity to plasma proteins. Signup and view all the answers

Why is the oral route of drug administration considered relatively safe?

Drugs enter the system more gradually, preventing large spikes in plasma levels. Signup and view all the answers

What is a key benefit of oral drug administration?

It is the simplest method, particularly for self-administration. Signup and view all the answers

What is the potential risk associated with routes that are NOT oral?

Sudden high plasma drug concentration. Signup and view all the answers

What must be understood in order to be aware of possible problems with drug metabolism?

How the body processes and eliminates a drug. Signup and view all the answers

Why is it important to understand pharmacokinetic principles?

To understand why drugs are administered through specific routes. Signup and view all the answers

What will be covered after the discussion of drug administration, absorption, and distribution in the text?

Drug metabolism. Signup and view all the answers

What is the primary benefit of administering drugs via inhalation?

Rapid entry of the drug into the bloodstream through a large alveolar surface. Signup and view all the answers

Why are drugs administered parenterally not subject to first-pass inactivation?

They directly enter the bloodstream bypassing the liver. Signup and view all the answers

In what setting is the use of an indwelling IV cannula most advantageous?

When controlled steady infusion of a drug is needed over time. Signup and view all the answers

What is a primary disadvantage of parenteral routes, such as intravenous injection?

The sudden appearance of high drug concentrations can cause adverse reactions. Signup and view all the answers

Which route of drug administration is MOST likely to be used by anesthesia providers for volatile general anesthetics?

Inhalation Signup and view all the answers

Why is intra-arterial drug administration considered a difficult and dangerous procedure?

It is difficult to perform and there is a higher risk of complications. Signup and view all the answers

What is a key advantage of intra-arterial drug administration, despite the risks?

It permits a large amount of medication to reach a specific tissue or organ. Signup and view all the answers

Which of the following characteristics is NOT an advantage of administering a drug through the inhalation route?

It will bypass the first pass metabolism. Signup and view all the answers

What is a primary limitation of subcutaneous (SC) injections?

The injected drugs must not irritate or inflame tissues. Signup and view all the answers

Why is the intramuscular (IM) route beneficial for the administration of botulinum toxin?

It allows for targeted delivery directly to the affected muscles. Signup and view all the answers

What advantage does IM injection have over intravenous (IV) injection in terms of drug plasma levels?

IM injection provides a more consistent and sustained release, avoiding large spikes in drug plasma levels. Signup and view all the answers

Which of the following best describes how topical medications are used to treat eye and ear problems?

Applied locally using eyedrops and eardrops, for localized effect. Signup and view all the answers

How can topical administration on mucous membranes be used to achieve systemic effects?

Through rapid absorption of the drug across the mucous membrane. Signup and view all the answers

What potential risk is associated with using topical drugs on mucous membranes for systemic effects?

Potential for adverse systemic effects from excessive absorption. Signup and view all the answers

Which route of administration provides a relatively rapid effect while preventing a sudden spike in plasma drug levels?

Intramuscular injection. Signup and view all the answers

Which of these is NOT a common example of a topical drug?

Medroxyprogesterone used as a contraceptive Signup and view all the answers

What is the primary mechanism by which phonophoresis enhances medication delivery?

Employing ultrasound waves to increase the skin's permeability. Signup and view all the answers

Why are biological membranes crucial in drug distribution within the body?

They act as barriers allowing for controlled passage of certain substances. Signup and view all the answers

What is the composition of membrane lipids that contributes to their selective barrier function?

Lipids made of a polar head and a non-polar, hydrophobic tail. Signup and view all the answers

In the context of physical therapy, what is the primary purpose of using iontophoresis and phonophoresis?

To deliver analgesic and anti-inflammatory medication to specific tissues. Signup and view all the answers

Which functional characteristic of biological membranes most directly influences their ability to control the passage of drug molecules?

The selective barrier they create due to the hydrophobic and hydrophilic properties of lipids. Signup and view all the answers

What is the difference between the mechanisms of iontophoresis and phonophoresis in transdermal medication delivery?

Iontophoresis utilizes electrical charge; phonophoresis employs ultrasound waves. Signup and view all the answers

How do physical therapists ensure the safe and effective use of iontophoresis and phonophoresis?

By adhering to physician-prescribed medications and specific parameters of use. Signup and view all the answers

Why do drugs often need to cross multiple membrane barriers to reach their therapeutic target?

Because the body is compartmentalized, with drugs needing to traverse barriers. Signup and view all the answers

Study Notes

Pharmacokinetics I: Drug Administration, Absorption, and Distribution

Pharmacokinetics studies how the body absorbs, distributes, and eliminates drugs.
Understanding how drugs are administered is critical for therapeutic effects.
Administering drugs via certain routes affects their absorption, distribution, and metabolism.

Routes of Administration

Enteral: Drug delivery through the alimentary canal.
- Oral: Most common, easiest, relatively safe.
  - Drugs metabolized in the liver (first-pass effect)
  - Absorption primarily in the small intestine.
  - Lipid solubility affects absorption (poor absorption by non-lipid soluble compounds).
  - Factors affecting absorption: GI issues, food, blood flow.
- Sublingual/Buccal: Placed under the tongue or between cheek and gum.
  - Avoids first-pass effect.
  - Rapid absorption.
- Rectal: Use suppositories.
  - Less efficient absorption, potential irritation.
  - Useful in unconscious/vomiting patients
Parenteral: Non-GI tract routes.
- Inhalation: Drugs in gaseous/aerosol form.
  - Pulmonary administration, rapid absorption due to large surface area.
  - Potential irritation of respiratory tract.
- Injection: Various methods (IV, IM, SC, intrathecal).
  - Intravenous (IV): Direct into vein; rapid onset, high bioavailability, potential for adverse reactions.
  - Intramuscular (IM): Into muscle; slower onset, can cause pain.
  - Subcutaneous (SC): Under the skin, slower absorption, ideal for sustained release.
  - Intrathecal: Into spinal subarachnoid space
- Topical: Applied to skin or mucous membranes.
  - Primarily treats local issues.
  - Some absorption, potential for systemic effects.
- Transdermal: Through skin.
  - Sustained drug release; avoids first-pass effect.

Bioavailability and Drug Absorption

Bioavailability: Percentage of administered drug reaching the bloodstream.
- Affected by the route of administration and the drug's properties.
Cell membranes: Barriers for drug absorption.
- Lipids and proteins make up the cell membrane.
- Drug absorption depends on lipid solubility and membrane penetration.

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Description

This quiz explores the principles of pharmacokinetics with a focus on drug administration, absorption, and distribution. It highlights the various routes of drug delivery and their impact on therapeutic effects. Understand the significance of factors affecting drug absorption for effective pharmacotherapy.