Pharmacology: Medication Metabolism

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Questions and Answers

What is a potential outcome of a long half-life for medications in malnourished clients?

Medications must be taken more frequently.

Increased risk for medication accumulation and toxicity. (correct)

Reduced therapeutic effects over time.

Medications are eliminated faster.

What does pharmacodynamics primarily describe?

The interactions between medications and body systems. (correct)

The method of medication storage in the body.

The process of medication absorption.

The elimination routes for medications.

Which of the following statements about agonists is correct?

They primarily inhibit medication efficacy.

They mimic endogenous compounds. (correct)

They block receptor activity.

They cannot activate receptors.

How do medications with a long half-life affect dosing intervals?

Dosing can be extended without loss of therapeutic effect. Signup and view all the answers

What is the primary pathway for the excretion of medications?

The kidneys primarily. Signup and view all the answers

What effect do pro-drugs have upon activation?

They convert into active drug forms. Signup and view all the answers

What can increase toxicity in medications?

Activation of inactive forms to active forms. Signup and view all the answers

Which of the following describes a mechanism of action for medications?

They cause functional changes in target cells. Signup and view all the answers

What is primarily affected by the presence of stool in the rectum during medication absorption?

The extent of tissue contact with the medication Signup and view all the answers

Which of the following describes the impact of binding to plasma proteins on medication efficacy?

Competition for protein sites can lead to toxicity Signup and view all the answers

In which organ does the majority of metabolism of medications occur?

Liver Signup and view all the answers

Why is it important to monitor medications with a low therapeutic index?

They have a narrow safety margin Signup and view all the answers

How does age impact medication metabolism in infants?

They have a limited medication-metabolizing capacity Signup and view all the answers

What is the significance of a medication's peak level?

It is the time when absorption equals elimination Signup and view all the answers

Which factor does NOT influence the rate of medication metabolism?

Time of day Signup and view all the answers

What can be a potential consequence of two medications competing for the same binding sites?

Reduced overall effectiveness Signup and view all the answers

How does aging generally affect medication doses for older adults?

They may need smaller doses due to potential accumulation. Signup and view all the answers

What is the purpose of obtaining a trough level blood sample?

To measure the concentration before the next dose. Signup and view all the answers

What does the term 'half-life' (t½) refer to in pharmacology?

The duration needed for the medication to drop by 50% in the body. Signup and view all the answers

What is a common effect of the first-pass metabolism on medications?

Inactivation of some medications after their first encounter with the liver. Signup and view all the answers

Why might older adults experience medication accumulation?

Decreased metabolic processes and smaller medication doses. Signup and view all the answers

What is indicated by a short half-life in medication?

The medication is likely to require frequent dosing. Signup and view all the answers

How can similar metabolic pathways affect concurrent medications?

They may alter the metabolism, leading to potential accumulation. Signup and view all the answers

What typically happens to hepatic medication metabolism as individuals age?

It tends to decline. Signup and view all the answers

What is the appropriate position for clients after instilling ear drops?

Side-lying position for 2 to 3 minutes Signup and view all the answers

Which phrase correctly describes the sublingual method of administration?

Placed under the tongue Signup and view all the answers

What should clients avoid doing while the sublingual tablet is in place?

Eating or drinking Signup and view all the answers

What technique should be employed when administering nasal medications?

Medical aseptic technique Signup and view all the answers

Why is a spacer used with nasal medication devices?

To increase medication delivery to the lungs Signup and view all the answers

What is the correct instruction regarding breath-holding after nasal medication administration?

Hold breath for 10 seconds Signup and view all the answers

What should clients do to facilitate effective instillation of nasal drops?

Lie supine with head positioned correctly Signup and view all the answers

Which statement accurately describes buccal administration?

Placed between the cheek and gum Signup and view all the answers

How many times per day is the medication expected to be administered?

Two Signup and view all the answers

Which factor is relevant for administering lower medication dosages?

Liver failure Signup and view all the answers

What is an appropriate action when administering eye drops?

Ask the client to look up at the ceiling. Signup and view all the answers

Which statement indicates that the client understands the use of transdermal patches?

I will apply the patch to an area of skin with no hair. Signup and view all the answers

What should the nurse verify regarding the client's medication?

Verify the trough level of the medication. Signup and view all the answers

Which of the following is a barrier to medication absorption?

Presence of food in the stomach. Signup and view all the answers

What instruction should the nurse provide regarding a metered-dose inhaler (MDI) with a spacer?

Exhale completely before using the inhaler. Signup and view all the answers

Which action is incorrect when instilling eye drops?

Asking the client to keep their eyes closed during application. Signup and view all the answers

Study Notes

Medication Metabolism

Factors influencing the rate of medication metabolism:
- Age: Infants have limited capacity, while older adults may experience a decline in hepatic medication metabolism, potentially requiring lower doses to avoid accumulation.
- Increased medication-metabolizing enzymes: Can lead to faster metabolism, requiring higher dosages.
- First-pass effect: This occurs when the liver inactivates medications on their first pass, requiring nonenteral routes like sublingual or IV for medications with high first-pass effect.
- Similar metabolic pathways: Medications shared by the same metabolic pathway can affect each other's metabolism, potentially leading to accumulation.

Excretion

Primarily occurs through the kidneys, but also through the liver, lungs, intestines, and exocrine glands.

Pharmacodynamics

Explanations of medication interactions with cells, systems, and organs to produce effects.
Medications can act as agonists (mimicking endogenous compound activity) or antagonists (blocking endogenous compound activity).

Therapeutic Index (TI)

Medications with a high TI have a wide safety margin, making routine blood level monitoring unnecessary.
Medications with a low TI require close monitoring of medication levels.

Half-Life (t½)

The time it takes for the medication in the body to decrease by 50%.
Liver and kidney function influence half-life.
It typically takes four half-lives to achieve a steady blood concentration.

Short Half-Life

Medications leave the body quickly, usually within 4 to 8 hours.
Short dosing interval is required to maintain therapeutic effectiveness.

Long Half-Life

Medications leave the body more slowly, over 24 hours.
Increased risk of medication accumulation and toxicity.
Medications can be administered at longer intervals.

Absorption

Barriers to absorption: Rectal - Presence of stool; Vaginal - Infectious material.
Absorption patterns: Sublingual - Directly to bloodstream, bypassing the liver; Buccal- Between cheek and gum, bypassing the liver
Transdermal - Through the skin, slow and sustained release.
Inhalation - Via the lungs

Administration

Ear drops: Instill directly into the outermost part of the ear canal, client should remain in a side-lying position for 2-3 minutes.
Nasal drops: Breathe through the mouth, stay in a supine position, and avoid blowing the nose for 5 minutes.
MDI (Metered Dose Inhaler) with a spacer: Use medical aseptic technique, exhale completely, hold breath for 10 seconds, slowly exhale through pursed lips, resume normal breathing.

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Description

This quiz explores the intricacies of medication metabolism, including factors like age, enzyme levels, and the first-pass effect. Understanding how these elements influence drug metabolism and excretion is crucial for effective drug therapy. Test your knowledge on pharmacodynamics and the interactions of medications within the body.