Antibacterial Drugs, Penicillins

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Questions and Answers

Why are drugs like amoxicillin combined with clavulanate potassium?

To directly enhance the drug's bactericidal activity against the bacteria.
To reduce the risk of IgE-mediated sensitivity reactions in patients.
To broaden the spectrum of bacteria that the drug can target effectively.
To prevent bacterial beta-lactamase from inactivating the antibiotic. (correct)

A patient develops anaphylaxis after being administered penicillin. Besides epinephrine, what strategy could be employed to mitigate future hypersensitivity, assuming penicillin remains the most suitable antibiotic?

Reduce the dose of penicillin and gradually increase it under close supervision. (correct)
Utilize a desensitization protocol involving high doses of corticosteroids.
Administer antihistamines prophylactically before each dose of penicillin.
Switch to a different class of antibiotics to avoid cross-reactivity.

Why are some cephalosporins classified as "generations"?

To show the progression of their effectiveness against Gram-positive bacteria.
To denote their reduced potential for cross-reactivity with penicillins.
To indicate their increased ability to penetrate the blood-brain barrier.
To classify their spectrum of activity and resistance to beta-lactamases. (correct)

In what scenario would cefepime be preferred over ceftriaxone?

When a broader spectrum antibiotic is needed, as cefepime covers both Gram-positive and Gram-negative bacteria and crosses the blood-brain barrier. (C) Signup and view all the answers

Why is ceftaroline a valuable asset in antimicrobial therapy?

It is effective against methicillin-resistant Staphylococcus aureus (MRSA). (D) Signup and view all the answers

Why are carbapenems typically reserved for more severe or resistant infections?

To minimize the development of resistance, reserving them for situations where other antibiotics may not be effective. (A) Signup and view all the answers

What is the primary mechanism of action that distinguishes glycopeptides (e.g., vancomycin) from beta-lactam antibiotics?

Glycopeptides inhibit both RNA synthesis and cell wall precursors, while beta-lactams specifically target transpeptidases in cell wall synthesis. (B) Signup and view all the answers

Why does vancomycin require therapeutic drug monitoring?

To minimize the risk of ototoxicity and nephrotoxicity by maintaining drug levels within a safe range. (B) Signup and view all the answers

What boxed warning is associated with Polymyxin B?

Nephrotoxicity and neurotoxicity (D) Signup and view all the answers

What distinguishes the mechanism of action of Polymyxin E from that of other cell wall inhibitors?

Polymyxin E directly disrupts the bacterial cytoplasmic membrane, while other cell wall inhibitors interfere with peptidoglycan synthesis. (D) Signup and view all the answers

In the context of antibacterial drugs, what is the key distinction between a bactericidal and a bacteriostatic agent?

Bactericidal agents eliminate bacteria directly, while bacteriostatic agents inhibit bacterial replication without necessarily killing them. (A) Signup and view all the answers

Considering the origins of antibacterial drugs, how do semi-synthetic penicillins like amoxicillin differ from purely synthetic antibacterial agents?

Semi-synthetic penicillins are developed through chemical modifications of naturally occurring compounds, while synthetic agents are entirely lab-created. (C) Signup and view all the answers

What is the specific enzymatic target of penicillins in bacterial cell wall synthesis?

Transpeptidase, which forms the A-A bridges in the cell wall. (A) Signup and view all the answers

How does first-generation cephalosporin (e.g., cephalexin) spectrum of activity differ from later generations, such as cefepime?

First-generation cephalosporins primarily target Gram-positive bacteria, whereas later generations have expanded activity against Gram-negative organisms. (C) Signup and view all the answers

What aspect of third-generation cephalosporins (e.g., ceftriaxone, cefdinir) dictates their clinical use in treating certain infections?

Their ability to cross the blood-brain barrier (BBB), making them useful in treating meningitis. (B) Signup and view all the answers

Considering the potential for cross-reactivity between penicillins and cephalosporins, what precaution should a healthcare provider take?

Use cephalosporins with caution in patients with a history of penicillin allergy, as there is a chance of cross-reactivity. (C) Signup and view all the answers

What characteristics differentiate Penicillin G from Penicillin VK?

Penicillin G can only be administered parenterally, while Penicillin VK is suitable for oral administration and acts on Gram +ve bacteria. (C) Signup and view all the answers

What benefit do ampicillin and amoxicillin offer over Penicillin G and Penicillin VK?

They possess a broader spectrum of activity, which is important for use against all bacteria. (D) Signup and view all the answers

What is the primary mechanism by which bacteria develop resistance to penicillins?

Producing beta-lactamase enzymes that inactivate penicillin. (A) Signup and view all the answers

How do sulbactam and tazobactam enhance the efficacy of penicillin-based antibiotics?

They inhibit beta-lactamase, protecting penicillins from enzymatic breakdown. (D) Signup and view all the answers

Why is epinephrine used in cases of anaphylaxis resulting from penicillin administration?

To reverse systemic vasodilation and bronchoconstriction, key effects of anaphylaxis. (A) Signup and view all the answers

What is the implication of cross allergenicity observed between penicillins and carbapenems?

Patients should be monitored for allergic reactions when administered carbapenems after a known penicillin allergy. (B) Signup and view all the answers

Why is alcohol consumption generally discouraged when taking certain antibacterial drugs?

Alcohol interferes with the liver's ability to metabolize the drug, increasing its concentration and risk of side effects. (D) Signup and view all the answers

How does the dual mechanism of action of vancomycin contribute to its effectiveness against resistant strains?

By attacking both RNA synthesis and cell wall precursors, making it harder for bacteria to develop resistance. (C) Signup and view all the answers

What characteristic of carbapenems makes them less susceptible to resistance compared to some other beta-lactam antibiotics?

They are resistant to beta-lactamase enzymes, which commonly inactivate other beta-lactam antibiotics. (C) Signup and view all the answers

Flashcards

Bactericide

Agents that directly kill bacteria.

Bacteriostatic

Agents that inhibit bacterial replication without directly killing the bacteria.