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Questions and Answers
What is the mechanism of action of beta-lactam antibiotics?
What is the mechanism of action of beta-lactam antibiotics?
- Inhibition of protein synthesis
- Inhibition of cell wall synthesis by binding to specific receptors (PBPs) and inhibiting transpeptidase enzymes (correct)
- Disruption of cell membrane function
- Inhibition of DNA replication
What is the effect of beta-lactamase on the activity of beta-lactam antibiotics?
What is the effect of beta-lactamase on the activity of beta-lactam antibiotics?
- Increases antibacterial activity
- Has no effect on antibacterial activity
- Converts beta-lactam antibiotics to a more active form
- Decreases antibacterial activity (correct)
Which of the following is a characteristic of penicillin G?
Which of the following is a characteristic of penicillin G?
- It is resistant to gastric acid (correct)
- It is resistant to beta-lactamase
- It is primarily excreted in the bile
- It is a broad-spectrum antibiotic
What is the purpose of combining beta-lactam antibiotics with beta-lactamase inhibitors?
What is the purpose of combining beta-lactam antibiotics with beta-lactamase inhibitors?
Which of the following is a use of procaine and benzathine penicillin G?
Which of the following is a use of procaine and benzathine penicillin G?
What is the half-life of penicillin G?
What is the half-life of penicillin G?
What is the main difference between penicillin and cephalosporins?
What is the main difference between penicillin and cephalosporins?
What is the main mechanism of resistance to penicillin?
What is the main mechanism of resistance to penicillin?
Which of the following antibiotics is used to treat Staphylococcal infections?
Which of the following antibiotics is used to treat Staphylococcal infections?
What is the main advantage of using Piperacillin and Ticarcillin over Ampicillin and Amoxicillin?
What is the main advantage of using Piperacillin and Ticarcillin over Ampicillin and Amoxicillin?
What is the main characteristic of 3rd generation cephalosporins?
What is the main characteristic of 3rd generation cephalosporins?
What is the main route of elimination for most cephalosporins?
What is the main route of elimination for most cephalosporins?
What is the mechanism of action of Clindamycin?
What is the mechanism of action of Clindamycin?
What is the primary route of elimination of Clindamycin?
What is the primary route of elimination of Clindamycin?
Which of the following is a common mechanism of resistance to Clindamycin?
Which of the following is a common mechanism of resistance to Clindamycin?
What is a common side effect of Clindamycin?
What is a common side effect of Clindamycin?
What is a common indication for Clindamycin?
What is a common indication for Clindamycin?
What is the mechanism of action of quinupristin-dalfopristin against gram-positive cocci?
What is the mechanism of action of quinupristin-dalfopristin against gram-positive cocci?
What is the primary route of excretion for quinupristin-dalfopristin?
What is the primary route of excretion for quinupristin-dalfopristin?
What is the Primary indication for the use of quinupristin-dalfopristin?
What is the Primary indication for the use of quinupristin-dalfopristin?
What is the half-life of quinupristin?
What is the half-life of quinupristin?
What is the mechanism of resistance to quinupristin-dalfopristin?
What is the mechanism of resistance to quinupristin-dalfopristin?
What is the primary limitation of using linezolid?
What is the primary limitation of using linezolid?
What is the mechanism of action of sulfonamides?
What is the mechanism of action of sulfonamides?
What is the consequence of displacing bilirubin from plasma protein binding?
What is the consequence of displacing bilirubin from plasma protein binding?
What is the primary route of excretion for sulfonamides?
What is the primary route of excretion for sulfonamides?
What is the indication for Sulfasalazine?
What is the indication for Sulfasalazine?
What is the consequence of crystalluria in sulfonamide therapy?
What is the consequence of crystalluria in sulfonamide therapy?
What is the mechanism of action of Trimethoprim?
What is the mechanism of action of Trimethoprim?
What is the consequence of sulfonamide toxicity on the hematological system?
What is the consequence of sulfonamide toxicity on the hematological system?
What is the indication for Cotrimoxazole?
What is the indication for Cotrimoxazole?
What is the effect of sulfonamides on mammalian cells?
What is the effect of sulfonamides on mammalian cells?
What is the half-life of Sulfamethoxazole?
What is the half-life of Sulfamethoxazole?
Flashcards
Penicillin V
Penicillin V
A penicillin derivative particularly effective against infections in the mouth and throat after tooth removal.
Very-Narrow-Spectrum Penicillinase-Resistant Agents
Very-Narrow-Spectrum Penicillinase-Resistant Agents
A group of penicillins resistant to breakdown by penicillinase, an enzyme produced by some bacteria.
Methicillin
Methicillin
The first penicillin to be used against staph infections, now often used as a model drug for this purpose.
Methicillin-induced nephritis
Methicillin-induced nephritis
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MRSA & MRSE
MRSA & MRSE
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Ampicillin and Amoxicillin
Ampicillin and Amoxicillin
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Synergistic effect
Synergistic effect
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Piperacillin and Ticarcillin
Piperacillin and Ticarcillin
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Cephalosporins
Cephalosporins
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Dihydrothiazine ring
Dihydrothiazine ring
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Cephalosporin Generations
Cephalosporin Generations
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Cephalexin
Cephalexin
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Pharmacokinetics
Pharmacokinetics
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Hepatic metabolism of cephalosporins
Hepatic metabolism of cephalosporins
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Renal tubular excretion of cephalosporins
Renal tubular excretion of cephalosporins
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Ceftriaxone and Cefoperazone
Ceftriaxone and Cefoperazone
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Cephalosporin resistance
Cephalosporin resistance
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Clindamycin
Clindamycin
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Bacteriostatic Activity
Bacteriostatic Activity
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Anaerobic Infections
Anaerobic Infections
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Superinfection
Superinfection
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Lincosamides
Lincosamides
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Quinupristin/Dalfopristin
Quinupristin/Dalfopristin
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Bactericidal Activity
Bactericidal Activity
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Arthralgia-myalgia syndrome
Arthralgia-myalgia syndrome
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CYP3A4
CYP3A4
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Oxazolidinones
Oxazolidinones
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23S rRNA
23S rRNA
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Sulfonamides
Sulfonamides
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PABA (para-aminobenzoic acid)
PABA (para-aminobenzoic acid)
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Trimethoprim
Trimethoprim
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Cotrimoxazole
Cotrimoxazole
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Hypersensitivity Reactions
Hypersensitivity Reactions
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Beta-lactam Antibiotics
Beta-lactam Antibiotics
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Transpeptidase enzymes
Transpeptidase enzymes
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Enzymatic hydrolysis
Enzymatic hydrolysis
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Study Notes
Penicillin and its Derivatives
- Penicillin V: Effective for oropharyngeal infections following dental extraction.
- Very-Narrow-Spectrum Penicillinase-Resistant Agents: Includes Methicillin, Nafcillin, and Oxacillin; resistant to penicillinase.
- Methicillin: Prototype agent for treating staphylococcal infections; known to cause nephritis.
- Resistance: MRSA (methicillin-resistant Staphylococcus aureus) and MRSE (methicillin-resistant Staphylococcus epidermis) are resistant to methicillin.
- Ampicillin and Amoxicillin: Broader spectrum; effective against Enterococci, E. coli, H. influenzae, L. monocytogenes (dangerous for pregnant women), P. mirabilis, and M. catarrhalis. Synergistic effect with aminoglycosides.
- Piperacillin and Ticarcillin: Target gram-negative bacteria, including Pseudomonas, Enterobacter, and Klebsiella species; also show synergy with aminoglycosides.
Cephalosporins
- Structural Characteristics: Cephalosporins differ from penicillins with a dihydrothiazine ring and acyl side chains (R1 and R2).
- Generations: Classified based on their development; 1st Generation (Cephalexin, Cefazolin) generally targets Gram-positive bacteria.
- Pharmacokinetics: Metabolized in the liver, mainly excreted via renal tubular excretion, except Ceftriaxone and Cefoperazone (excreted in bile).
- Resistance: Cephalosporins exhibit varying resistance profiles from 1st to 3rd Generation, increasing coverage against Gram-negative organisms.
Clindamycin and Lincosamides
- Clindamycin: Binds to the 50S ribosomal subunit, exhibiting bacteriostatic activity; effective against Gram-positive cocci and anaerobic bacteria.
- Toxicities: Can lead to severe anaerobic infections, skin rashes, toxic shock syndrome, and superinfections.
- Combination Therapy: Often paired with aminoglycosides for serious infections such as necrotizing fasciitis.
Streptogramins
- Quinupristin/Dalfopristin: Bactericidal against most Gram-positive cocci; effective against MRSA and vancomycin-resistant E. faecium.
- Mechanism: Binds to the 50S ribosomal subunit, causing protein synthesis disruption.
- Toxicities and Drug Interactions: May cause arthralgia-myalgia syndrome; interacts with drugs metabolized by CYP3A4.
Oxazolidinones
- Linezolid and Tidezolid: Bind to the 23S rRNA of the 50S ribosomal subunit; prevent ribosome formation and exhibit bacteriostatic activity against streptococci.
Sulfonamides and Trimethoprim
- Sulfonamides: Bacteriostatic agents that inhibit folic acid synthesis by competing with PABA; used for uncomplicated UTIs and ocular infections.
- Trimethoprim: Inhibits dihydrofolate reductase, blocking the formation of active tetrahydrofolate.
- Cotrimoxazole: Combination of trimethoprim and sulfamethoxazole; provides synergistic inhibition of folate synthesis and expanded activity against various infections.
- Toxicities: Potential for hypersensitivity reactions, gastrointestinal disturbances, and hematologic toxicity.
General Pharmacokinetics and Resistance
- Basic Mechanism of Action (MOA): Beta-lactam antibiotics disrupt cell wall synthesis by inhibiting transpeptidase enzymes, leading to bacterial cell lysis.
- Resistance: Common mechanisms include enzymatic hydrolysis by beta-lactamases and modifications in target sites.
Important Considerations
- Drug Interactions: Some antibiotics displace other drugs from plasma proteins, potentially increasing their free concentrations and toxicity.
- Adverse Effects: Includes skin toxicity, gastrointestinal upsets, and possible renal implications, necessitating cautious use in specific populations, such as the elderly or with pre-existing conditions.
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Description
This quiz covers the characteristics and mechanism of action of beta-lactam antibiotics, specifically penicillins, including their MOA, pharmacokinetics, resistance, and drug interactions.