Antibiotics Overview and Classes

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Questions and Answers

What is a common adverse effect associated with sulfonamides?

Photosensitivity (correct)

Prolonged QT interval

Nausea (correct)

Chest pain

Which of the following drug classes is indicated for treating MRSA infections?

Cephalosporins

Macrolides

Aminoglycosides

Sulfonamides (correct)

What is the mechanism of action for macrolides?

Inhibit protein synthesis (correct)

Inhibit bacterial DNA replication

Enhance bacterial cell wall synthesis

Inhibit bacterial growth

Which adverse effect is specifically associated with sulfonamides leading to a severe reaction?

Stevens-Johnson syndrome Signup and view all the answers

Which of the following interactions is commonly noted with macrolides?

Oral contraceptives Signup and view all the answers

What is the purpose of obtaining blood cultures and sensitivities before starting antibiotic treatment?

To identify the specific bacteria causing the infection Signup and view all the answers

Which of the following antibiotic classes is specifically mentioned to work on gram-positive bacteria?

Penicillin Signup and view all the answers

What is a potential side effect of penicillin?

Angioedema Signup and view all the answers

What action should be taken if the bacteria is found to be resistant to the prescribed antibiotic?

Request a new antibiotic Signup and view all the answers

Which generation of antibiotics is less resistant to beta lactamase?

First generation Signup and view all the answers

What is the mechanism of action (MOA) of cephalosporins?

Disrupting bacterial cell wall formation Signup and view all the answers

Which of the following does NOT fall within the sub-classes of antibiotics mentioned?

Tetracyclines Signup and view all the answers

What is a superinfection, as described in the notes?

Loss of normal flora leading to infections Signup and view all the answers

What is one major adverse effect associated with the use of fluoroquinolones?

Achilles tendon rupture Signup and view all the answers

Which of the following is a consideration when administering glycopeptide antibiotics?

Monitor trough levels between 10-20 mg/L Signup and view all the answers

Tetracyclines are contraindicated in children under what age?

8 years Signup and view all the answers

Which drug is classified as a nitroimidazole?

Metronidazole Signup and view all the answers

What is the mechanism of action (MOA) for tetracyclines?

Inhibit protein synthesis Signup and view all the answers

Which of the following conditions does NOT indicate a need for monitoring in anti-tubercular drug treatment?

Blood pressure fluctuations Signup and view all the answers

What common interaction should be considered when prescribing tetracyclines?

Dairy products and anti-acids Signup and view all the answers

In treating bacterial infections caused by MRSA, which antibiotic is primarily used?

Vancomycin Signup and view all the answers

Study Notes

Antibiotics

Spectrum: Broad-spectrum antibiotics are used initially, then narrowed to specific types based on culture and sensitivity results.
Empiric Treatment: Given when the causative organism is unknown, based on the most likely bacteria.
Culture & Sensitivity: Helps determine the specific bacteria causing the infection and its susceptibility to antibiotics.
Resistance: When a bacteria is resistant to a prescribed antibiotic, a new antibiotic is requested.
Superinfection: Occurs when the body's normal flora is affected by antibiotics, leading to infections like C. diff or vaginal yeast infections.
Importance of Completion: Do not stop taking antibiotics even if symptoms improve; completing the full course is crucial.

Antibiotic Subclasses

Penicillin:
- MOA: Disrupts bacterial cell wall synthesis.
- Drugs: End in “CILLIN” (e.g., penicillin G, amoxicillin, amoxicillin/clavulanic acid).
- Indications: Effective against Gram-positive bacteria, particularly Streptococcus.
- Side Effects: Nausea, vomiting, diarrhea, rash, angioedema.
- Interactions: Oral contraceptives, cross-reactivity with cephalosporins.
Cephalosporins:
- MOA: Disrupt bacterial cell walls by inhibiting peptidoglycan formation.
- Drugs: Begin with “CEF or CEPH” (e.g., Cefazolin, cephalexin, ceftriaxone).
- Indications: Effective against Gram-positive cocci, Gram-negative cocci, bacilli, anaerobes, and surgical prophylaxis.
- Adverse Effects: Nausea, vomiting, diarrhea, angioedema, rash.
- Interactions: Cross-reactivity with penicillin, NSAIDs, H2 blockers, oral contraceptives.
Sulfonamides:
- MOA: Inhibits bacterial growth.
- Drug: Sulfamethoxazole/trimethoprim.
- Indications: Staph infections (MRSA), UTIs, Gram-positive and negative organisms.
- Adverse Effects: Nausea, vomiting, diarrhea, rash (Stevens-Johnson syndrome), photosensitivity.
- Contraindications: Sulfur allergy, crystalluria.
- Considerations: Increase fluid intake.
Macrolides:
- MOA: Inhibits bacterial protein synthesis.
- Drugs: End in “MYCIN” (e.g., Azithromycin, clarithromycin, erythromycin).
- Indications: STDs (Chlamydia), bacterial infections (pneumonia).
- Adverse Effects: Chest pain, palpitations, nausea, vomiting, diarrhea, rash, prolonged QT interval, ototoxicity.
- Interactions: Oral contraceptives.
- Consideration: Used when patients are allergic to penicillin and cephalosporins.
Aminoglycosides:
- MOA: Inhibits protein synthesis.
- Drugs: End in “MICIN or MYCIN” (e.g., Gentamicin, tobramycin).
- Indications: E. coli, prophylaxis (GI and GU symptoms), C. diff.
- Adverse Effects: Headaches, ototoxicity, kidney toxicity, nausea, vomiting.
- Considerations: Blood serum levels need to be monitored.
Tetracyclines:
- MOA: Inhibits protein synthesis.
- Drugs: End in “CYCLIN” (e.g., Tetracycline, doxycycline).
- Indications: Gram-positive and negative bacteria, acne, STIs, pneumonia.
- Adverse Effects: Nausea, vomiting, diarrhea, photosensitivity, teeth discoloration in children and fetuses.
- Interactions: Milk products, antacids.
- Contraindications: Children under 8, pregnancy.
- Considerations: Take milk or antacids 2 hours before or 3 hours after taking the antibiotic.
Fluoroquinolones:
- MOA: Destroys bacterial cell DNA synthesis.
- Drugs: End in “FLOXACIN” (e.g., Ciprofloxacin, levofloxacin, moxifloxacin).
- Indications: Gram-negative bacteria.
- Adverse Effects: Nausea, vomiting, diarrhea, headache, Achilles tendon rupture, prolonged QT interval, superinfection.
- Interactions: Blood thinners, anticoagulants, antacids, dairy products.
Nitroimidazoles:
- MOA: Inhibits protein synthesis.
- Drug: Metronidazole.
- Indications: Bacterial vaginosis, trichomoniasis, prophylaxis for surgery.
- Adverse Effects: Nausea, vomiting, diarrhea, headache, seizures, thrombocytopenia, neutropenia, superinfection (vaginal candidiasis).
Glycopeptide:
- MOA: Inhibits protein synthesis.
- Drug: Vancomycin.
- Indications: Bacterial infections, MRSA, C. diff.
- Adverse Effects: Red Man syndrome (flushing and itching), hypotension, tachycardia, ototoxicity, kidney toxicity.
- Considerations: Administered slowly over 1 hour, trough levels to be monitored (10-20), GFR > 60.

Anti-Tubercular Drugs

Tuberculosis (TB) Signs: Fever, night sweats, chills, fatigue, coughing up blood (hemoptysis), weight loss, anorexia.
Treatment Goals: Treat infected individuals, prevent complications, and prevent community spread.
Monitoring: TB patients may require monitoring for up to 2 years, including therapeutic effect monitoring.

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Description

This quiz covers essential concepts related to antibiotics, including their spectrum, empiric treatment, and the importance of completing the prescribed course. It also discusses subclasses like penicillin and the mechanisms of action involved. Test your knowledge on antibiotic resistance and the consequences of superinfections.