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Questions and Answers
To what classification of drug does penicillin belong?
To what classification of drug does penicillin belong?
Define β-lactamase.
Define β-lactamase.
β-lactamase is a bacterial enzyme that hydrolyzes the amide bond of the β-lactam ring.
What are penicillin-binding proteins (PBPs)?
What are penicillin-binding proteins (PBPs)?
Enzymes involved in the synthesis of the bacterial cell wall.
What are transpeptidases?
What are transpeptidases?
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What is the major mechanism by which penicillins kill bacteria?
What is the major mechanism by which penicillins kill bacteria?
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What additional mechanism is involved in the action of penicillins?
What additional mechanism is involved in the action of penicillins?
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Which type of organisms are not susceptible to penicillins?
Which type of organisms are not susceptible to penicillins?
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Do penicillins readily enter the central nervous system?
Do penicillins readily enter the central nervous system?
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How are the penicillins classified?
How are the penicillins classified?
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Match the following natural penicillins with their routes of administration:
Match the following natural penicillins with their routes of administration:
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How do the various natural penicillins differ from each other?
How do the various natural penicillins differ from each other?
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What can natural penicillin be used for?
What can natural penicillin be used for?
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Describe the absorption of these penicillins.
Describe the absorption of these penicillins.
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Is the absorption of penicillins influenced by food?
Is the absorption of penicillins influenced by food?
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How are these drugs excreted?
How are these drugs excreted?
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How can excretion of penicillins be altered?
How can excretion of penicillins be altered?
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What are the most common adverse effects seen with patients who are medicated with penicillin?
What are the most common adverse effects seen with patients who are medicated with penicillin?
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Are there adverse effects seen with all forms of penicillins?
Are there adverse effects seen with all forms of penicillins?
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Study Notes
Antimicrobial Classification
- Penicillin belongs to the β-lactams class of antimicrobial drugs, characterized by a four-membered lactam ring.
β-lactamase Enzyme
- β-lactamase, also known as penicillinase, is a bacterial enzyme that hydrolyzes the β-lactam ring’s amide bond.
Penicillin-binding Proteins (PBPs)
- PBPs are essential enzymes for bacterial cell wall synthesis and maintenance of bacterial morphology.
Transpeptidases
- Transpeptidases are enzymes that cross-link peptidoglycan chains, a key step in bacterial cell wall synthesis.
Mechanism of Action
- Penicillins kill bacteria by binding to PBPs and inhibiting transpeptidase, leading to bacterial lysis.
Role of Autolysins
- Penicillins trigger the release of autolysins, which assist in normal bacterial cell wall remodeling.
Organism Susceptibility
- Organisms that are not actively growing or lack a cell wall are not susceptible to penicillins.
Central Nervous System Distribution
- Penicillins typically do not penetrate the central nervous system (CNS) well, but can reach therapeutic levels during meningitis.
Classification of Penicillins
- Types of penicillins include:
- Natural penicillins
- Antistaphylococcal penicillins
- Antipseudomonal penicillins
- Extended-spectrum penicillins
Natural Penicillins and Administration Routes
- Examples of natural penicillins:
- Penicillin G: oral, intravenous, intramuscular
- Penicillin V: oral only
- Penicillin G procaine: intramuscular only
- Penicillin G benzathine: intramuscular only
Variations in Natural Penicillins
- Natural penicillins differ in routes of administration and gastric acid stability but share the same mechanism of action.
Clinical Uses of Natural Penicillin
- Natural penicillin is effective mainly against gram-positive bacteria, indicated for infections like:
- Streptococci
- Meningococci
- Clostridium
- Listeria
- Enterococci
- Diphtheria
- Anthrax
- Syphilis
- Treponema pallidum
- Actinomycosis
- Bacteroides species (except fragilis)
- Anaerobic organisms without β-lactamase production
Absorption Characteristics
- Absorption is influenced by acid stability and protein binding.
Food Interactions
- Food impacts the absorption of most penicillins; they should be taken 1 to 2 hours before or after meals, except for amoxicillin.
Excretion Mechanism
- Penicillins are primarily excreted unchanged in urine through glomerular filtration and active tubular secretion; some undergo hepatic inactivation.
Altering Excretion
- Co-administration of probenecid can delay renal tubular secretion of penicillins.
Common Adverse Effects
- Adverse effects of penicillins may include:
- Hypersensitivity reactions (anaphylaxis, urticaria, bronchospasm)
- Seizures (in patients with renal impairment)
- Gastrointestinal disturbances (diarrhea)
- Hemolytic anemia
- Cation toxicity due to excess sodium or potassium from high doses
Universal Toxicity
- Adverse effects apply to all penicillin forms, not limited to natural varieties.
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Description
Test your knowledge on penicillin and its classifications with these flashcards. This quiz covers essential terms like β-lactams and β-lactamase, providing a concise review of key concepts in antimicrobial drugs. Perfect for students studying pharmacology or microbiology.
