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Questions and Answers
Which route of drug administration is generally absorbed the fastest?
What factor generally causes oral drugs to be absorbed slower than those administered parenterally?
How does gastric acidity affect drug absorption when taken orally?
For optimal absorption of oral medications, when should they ideally be administered in relation to meals?
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Why are drugs administered intravenously more likely to cause toxic effects compared to oral medications?
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Which of the following is a reason for pharmaceutical companies to design drugs in tablet or capsule form?
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Which statement is true regarding intramuscular drug administration?
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What is a common misconception about oral drug administration compared to parenteral routes?
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What is a significant factor affecting drug distribution to tissues?
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Why might systemic drugs be less effective for a patient with a lower-leg infection and diabetes?
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How can environmental conditions affect drug delivery in patients?
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Why cannot many drugs reach the central nervous system (CNS)?
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What effect does inadequate tissue perfusion have on drug effectiveness?
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Study Notes
Drug Absorption and Administration Routes
- Oral administration is the most common route due to its convenience, safety, and cost-effectiveness. However, oral drugs undergo significant barriers, including the acidic environment of the stomach.
- Stomach acidity can break down or inactivate drugs, so pharmaceutical companies design capsules and tablets to release the active drug in a specific acidic environment.
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Food can influence stomach acidity and emptying rate, impacting drug absorption.
- High acidity from foods like dairy, alcohol, and protein can accelerate drug breakdown.
- Certain foods may bind to or block drug absorption.
- To minimize the impact of stomach acidity and food, oral drugs are generally recommended 1 hour before or 2 hours after a meal.
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Parenteral routes involve direct administration of drugs into the body, bypassing the gastrointestinal tract, and are generally absorbed faster than oral drugs.
- Intravenous (IV) administration delivers drugs directly into the bloodstream, resulting in immediate onset and full absorption. However, this route also carries a higher risk of toxicity due to the limited margin for error in dosing.
- Intramuscular (IM) administration involves injecting drugs into a muscle, where they are absorbed into the capillaries and enter circulation. Absorption rate is influenced by muscle vascularity, with men generally experiencing faster peak levels than women.
- Subcutaneous administration involves injecting drugs under the skin, where they are slowly absorbed into circulation. Absorption rate is influenced by fat content at the injection site and local circulation.
###Â Distribution of Drugs
- Distribution is the movement of a drug from the bloodstream to the body’s tissues.
- Factors that impact distribution include:
- Drug’s lipid solubility (how easily it dissolves in fats)
- Drug’s ionization (its electrical charge)
- Perfusion of the target tissue (how much blood flow the tissue receives)
Tissue Perfusion and Drug Delivery
- Poor tissue perfusion can hinder drug delivery to the target tissue.
- Example: A diabetic patient with a lower-leg infection may not respond well to systemic antibiotics due to decreased blood flow to the infected area.
- Explanation: If there’s limited blood flow, less antibiotic reaches the infected tissue, leading to ineffective treatment.
- Another Example: Individuals in cold environments experience vasoconstriction (narrowing of blood vessels) in extremities, reducing blood flow.
Blood-Brain Barrier and Drug Distribution
- Many drugs bind to proteins and are not lipid soluble.
- These drugs cannot cross the blood-brain barrier due to its selectivity for lipid-soluble substances.
- The blood-brain barrier is a protective mechanism that prevents harmful substances from reaching the central nervous system (CNS).
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Description
This quiz covers the various routes of drug administration, focusing on oral and parenteral methods. It discusses how factors like stomach acidity and food intake can impact drug absorption and efficacy. Learn about the advantages and challenges of different administration methods to understand their implications for patient care.
