Pharmacology of Cephalosporins and Antibiotics

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Questions and Answers

Which generation of cephalosporins is typically used for prophylaxis in surgical patients?

Third generation

Second generation

First generation (correct)

Fourth generation

A patient with a severe, hospital-acquired pneumonia caused by Pseudomonas is most likely to be treated with which generation of cephalosporin?

First generation

Second generation

Third generation

Fourth generation (correct)

What is the primary mechanism of action for cephalosporin antibiotics?

Interference with DNA replication

Inhibition of folic acid synthesis

Disruption of cell wall synthesis by binding to penicillin-binding proteins (correct)

Inhibition of protein synthesis

Which of the following adverse effects is commonly associated with vancomycin administration?

"Red man" syndrome Signup and view all the answers

Which antibiotic is considered the most effective beta-lactam for treating anaerobic bacterial infections?

Imipenem Signup and view all the answers

Which of the following best describes the concept of selective toxicity in antimicrobial drugs?

The ability of a drug to injure target cells or organisms without harming host cells in close contact. Signup and view all the answers

A medication that directly kills bacteria at clinically achievable concentrations is considered:

Bactericidal. Signup and view all the answers

Which of the following is NOT one of the four basic mechanisms by which bacteria can develop resistance to antimicrobial drugs?

Increasing the concentration of a drug at its site of action. Signup and view all the answers

What is a superinfection concerning antimicrobial drug therapy?

A new infection that appears during the course of treatment for a primary infection. Signup and view all the answers

Which of these is NOT a primary use for prophylactic antibiotics?

Treating a known bacterial infection. Signup and view all the answers

When selecting an antibiotic, which of the following host factors is the LEAST relevant?

The patient's personal preferences regarding specific brands of medicine. Signup and view all the answers

Which statement is most accurate regarding antimicrobial drugs?

They can be of natural or synthetic origin and can kill or suppress microorganisms. Signup and view all the answers

What is the primary reason for advising patients to complete the full course of an antibiotic prescription, even if they feel better?

To prevent the recurrence of the infection and delay the development of drug resistance Signup and view all the answers

Which of these drug actions is LEAST likely to be targeted by an antimicrobial drug?

Disrupting the host cell wall Signup and view all the answers

In the context of bacterial resistance, what does 'producing a drug antagonist' refer to?

Creating a substance that blocks the drug's action at its target site. Signup and view all the answers

A patient taking penicillin reports developing a rash and itching. What is the most appropriate initial action?

Stop the penicillin immediately and notify the physician. Signup and view all the answers

Which statement by a patient indicates a good understanding of antibiotic use?

I should continue taking the antibiotic until it is finished. Signup and view all the answers

What is the primary mechanism of action of penicillins?

Weakening the bacterial cell wall, leading to lysis. Signup and view all the answers

What factor contributes to bacterial resistance to penicillins?

Production of penicillin-binding proteins (PBPs) with low affinity. Signup and view all the answers

A patient has a documented history of a mild allergic reaction to penicillin. Which antibiotic class is most appropriate to consider?

Cephalosporins Signup and view all the answers

Which patient is most appropriate for prophylactic antibiotic therapy?

A patient scheduled to undergo a bowel resection. Signup and view all the answers

A patient with a known severe penicillin allergy requires antibiotic treatment. Which of the following actions is most appropriate?

Avoid penicillins and cephalosporins and chose alternative classes Signup and view all the answers

What is a key difference between the cell envelopes of gram-positive and gram-negative bacteria?

Gram-positive bacteria have two layers while gram-negative bacteria have three layers, including an outer membrane. Signup and view all the answers

What is the most appropriate response from a nurse when a pregnant adolescent patient asks about continuing her tetracycline prescription?

Tetracycline can be harmful to the baby’s teeth and should be avoided. Signup and view all the answers

A 6-week-old infant develops a severe cough. While awaiting culture results, which antibiotic is the nurse most likely to administer?

Erythromycin ethylsuccinate Signup and view all the answers

What is the primary use of aminoglycoside antibiotics?

Treating aerobic gram-negative bacilli infections. Signup and view all the answers

Which adverse effect is NOT commonly associated with aminoglycoside antibiotics?

Increased blood glucose levels Signup and view all the answers

Which approach is MOST appropriate for the nurse to administer the antidote for aminoglycoside induced neuromuscular blockade?

Administer via IV infusion of a calcium salt Signup and view all the answers

Why are serum levels of aminoglycosides monitored?

To ensure that peak levels are high enough to kill bacteria, and trough levels are low enough to minimize toxicity. Signup and view all the answers

For which specific clinical situation is amikacin (Amikin) considered the drug of choice (DOC)?

When gentamicin is ineffective due to resistance in hospitals. Signup and view all the answers

When should a nurse draw a blood sample to check for gentamicin peak levels after an IV infusion?

30 minutes after the IV infusion. Signup and view all the answers

A patient is prescribed clotrimazole for a dermatophytic infection. Which of the following adverse effects is most likely to be associated with topical administration of clotrimazole?

Stinging, erythema, and edema Signup and view all the answers

A patient with a fungal infection is prescribed nystatin. Which of the following routes of administration and associated adverse effects is MOST likely to occur?

Oral administration resulting in GI disturbance Signup and view all the answers

An individual is prescribed a medication that is a CYP3A4 inhibitor, which of the following medication effects could be present?

The medication will decrease the activity of CYP3A4, which will lead to increased levels of other medications Signup and view all the answers

A pregnant patient is prescribed a medication, and it is noted that in the first trimester the medication can cause serious birth defects. Which of the following is the safest action at this time?

Withhold the medication and contact provider immediately Signup and view all the answers

A patient is experiencing an oral candidiasis infection. Which of the following medications would be MOST appropriate as first-line treatment and why?

Oral nystatin, due to its specific action against candida which limits systemic effects. Signup and view all the answers

A patient receiving an intraperitoneal aminoglycoside develops a serious side effect. Which agent should the nurse anticipate administering?

Neuromuscular blocker Signup and view all the answers

Sulfonamides work by inhibiting the synthesis of which substance in bacteria?

Tetrahydrofolic acid Signup and view all the answers

A patient with a urinary tract infection is prescribed a sulfonamide. Which common adverse effect should the nurse monitor for?

Crystalluria Signup and view all the answers

A patient with 2nd and 3rd degree burns is prescribed silver sulfadiazine (Silvadene). The nurse should educate the patient that the application is typically:

Pain-free Signup and view all the answers

Which of the following conditions is silver sulfadiazine commonly used for?

Second and third degree burns Signup and view all the answers

A patient is prescribed Trimethoprim/sulfamethoxazole (Bactrim). What teaching point is most important for the nurse to include?

Drink 8 to 10 glasses of water each day. Signup and view all the answers

Which of the following is a potential adverse effect of Trimethoprim/sulfamethoxazole (Bactrim)?

Hyperkalemia Signup and view all the answers

What is the primary mechanism by which trimethoprim/sulfamethoxazole (Bactrim) is effective against bacterial infections?

Inhibition of sequential steps in bacterial folic acid synthesis Signup and view all the answers

Study Notes

Antibiotics & Anti-Infectives

Antibiotics are medicines used to treat infections
190 million doses are given each day in hospitals
Introduced in the 1930s and 1940s
Have greatly reduced illness and deaths from infections
Antibiotic: A chemical produced by microbes that harms others
Antimicrobial drug: Any chemical damaging microbes
Selective Toxicity: Drugs harm target cells without harming other cells. The target cell chemistry is different in mammals and microbes.
Cell Wall Synthesis: The cell wall in bacteria and the different chemistry prevents disruption of mammal cells
Inhibit bacterial cell growth, synthesis or other specific functions
Drugs target specific structures or functions that are present in bacteria, but not in human cells
Disruption of bacterial cell walls
Inhibition of specific enzyme unique to bacteria
Protein synthesis
Synthesis of nucleic acids
Antimetabolites
Viral enzyme inhibitors

Classification of Antibiotics

Bactericidal: Directly kills bacteria at clinically achievable concentrations
Bacteriostatic: Slows bacterial growth but doesn't kill them

Acquired Resistance to Antimicrobial Drugs

Organisms develop resistance over time
Actions that organisms take to reduce the effectiveness of an antibiotic therapy:
- Lowering the concentration of a drug at its target site
- Inactivating the drug
- Modifying the structure of its drug target
- Producing an antagonist to the drug

Antibiotic Use and Drug-Resistant Microbe Emergence

How antibiotic use leads to resistance:
- The extent of antibiotic use directly impacts resistance.
Antibiotics that promote resistance
Nosocomial (hospital-acquired) infections: Infections that occur while patients are being treated in a hospital, and superinfections which occur during treatment of a primary infection

Delaying Emergence of Drug Resistance

Promote appropriate antibiotic prescribing guidelines
Reduced demand for antibiotics in healthy individuals
Increase patient compliance with prescribed regimens

Host Factors (Host Defenses,)

Host defenses factors such as site of infection and previous allergic reactions that affect the choice of antibiotics
Patient variables: Allergies, drug interactions, and ability of the drug to reach the infection site

Prophylactic Use

Agents given to prevent infection: surgery, bacterial endocarditis, neutropenia, and other indications

What to teach patients.

Complete the full prescription
Notify physician immediately if signs of allergic reaction or side effect appear
Do not share medications with others
Store in cool, dry place, keeping out of reach of children

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Description

Test your knowledge on cephalosporins and their applications in antimicrobial therapy. This quiz focuses on the use, mechanisms, and effects of various antibiotics, with special emphasis on cephalosporins in surgical prophylaxis and treatment of infections. Prepare to assess concepts like selective toxicity and antibiotic resistance.