Pharmacology Module 8: Antimicrobial Agents

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Questions and Answers

What type of antibiotic is vancomycin?

Tricyclic glycopeptide (correct)

Polycyclic glycopeptide

Bicyclic glycopeptide

Monocyclic glycopeptide

What is the mechanism of action of vancomycin?

Inhibits bacterial protein synthesis

Inhibits bacterial RNA synthesis

Inhibits bacterial DNA replication

Inhibits bacterial cell wall synthesis (correct)

What is a common adverse effect of IV vancomycin administration?

Red neck syndrome

Chills and fever

Rash and urticaria

All of the above (correct)

What is vancomycin used to treat?

All of the above Signup and view all the answers

What type of bacteria is vancomycin effective against?

Gram-positive bacteria Signup and view all the answers

What can exposure to sunlight cause when taking certain medications?

Rash, itching, redness, or discoloration of the skin Signup and view all the answers

What type of infections are quinolones effective in treating?

Selected community-acquired and nosocomial infections Signup and view all the answers

How are quinolones usually administered?

Orally, but some can be given intravenously for serious infections Signup and view all the answers

What are fluoroquinolones known for?

Being generally very safe antibiotics Signup and view all the answers

What is isoniazid used to treat or prevent?

Tuberculosis (TB) or prevent its return Signup and view all the answers

What is the typical treatment duration for isoniazid and rifampicin for TB?

9 months Signup and view all the answers

What is a characteristic of chloramphenicol in neonates?

Ashen gray skin discoloration Signup and view all the answers

Why are sulfonamides bacteriostatic?

They inhibit the enzyme dihydropteroate synthase Signup and view all the answers

What is a possible consequence of taking sulfonamides for a long period of time?

Increased risk of infections Signup and view all the answers

Why should individuals taking sulfonamides be extra careful when using oral hygiene products?

To prevent bleeding of the gums Signup and view all the answers

What type of infections are sulfonamides ineffective against?

Viral infections Signup and view all the answers

What is a structural similarity between sulfonamides and another compound?

PABA Signup and view all the answers

What is the primary reason for administering vitamin B6 alongside a commonly used drug for prophylaxis and treatment of TB?

To prevent peripheral neuropathy Signup and view all the answers

What is the duration of the treatment regime for TB that involves rifampin and isoniazid?

6 months Signup and view all the answers

What is the primary indication for the use of rifampin?

Mycobacterial and gram-positive bacterial infections Signup and view all the answers

Why is rifampin rarely used alone?

Due to the risk of resistance developing rapidly Signup and view all the answers

What is the primary use of amphotericin B?

Treating systemic fungal infections Signup and view all the answers

What is the effectiveness of the 6-month treatment regime for TB?

83% Signup and view all the answers

What is the primary indication for the use of nystatin?

Candidal infections of the mucosa, skin, intestinal tract, or vagina Signup and view all the answers

What is the recommended duration of nystatin treatment?

For at least 10 days or for 48 hours after remission of symptoms Signup and view all the answers

How soon can nystatin start to work?

After 2 days Signup and view all the answers

What is the recommended dosage frequency for nystatin suspension?

Every 6 hours Signup and view all the answers

Why is it important to continue taking nystatin for 2 days after symptoms resolve?

To prevent the infection from coming back Signup and view all the answers

Study Notes

Exposure to Sunlight and Medications

Brief sunlight exposure can cause rash, itching, redness, discoloration, or severe sunburn.
It is essential to avoid unnecessary sun exposure while on certain medications.
Wearing sunscreen and protective clothing is recommended when outdoors.

Quinolones

Quinolones are effective antimicrobial agents against selected community-acquired and nosocomial infections.
Typically administered orally, some can be given intravenously for serious infections.
Bactericidal agents include Ciprofloxacin and Norfloxacin.
Useful in treating infections when beta-lactams, aminoglycosides, or vancomycin cannot be used.

Adverse Reactions of Quinolones

Fluoroquinolones are generally safe with few serious adverse reactions.
Common side effects include gastrointestinal issues (nausea, vomiting) and CNS reactions (dizziness, insomnia, headache).

Antituberculosis Agents

Key agents include Isoniazid, Rifampicin, and Ethambutol.
Combination therapy of Isoniazid + Rifampicin is prescribed for 9 months.
Isoniazid + Ethambutol is used for 18 months to treat or prevent TB.

Isoniazid

Used to treat and prevent tuberculosis (TB) reactivation.
Can be prescribed alone or in combination with other medicines.

Vancomycin

A tricyclic glycopeptide antibiotic derived from Streptococcus orientalis.
Primarily treats gram-positive bacterial infections, including MRSA.
Mechanism of action: bactericidal, inhibits bacterial cell wall synthesis.
Side effects include "red neck syndrome" and potential reactions like chills and fever.

Clinical Uses of Vancomycin

Indicated for Clostridioides difficile-associated diarrhea and pseudomembranous colitis.
Treats endocarditis and various Staphylococcal infections.

Sulfonamides

Not classified as antibiotics; structurally similar to PABA, which can trigger allergic reactions.
Mechanism of action: inhibits dihydropteroate synthase (DHPS), preventing folic acid production.
Clinical use includes urinary tract infections, inflammatory bowel disease, and skin infections.

Adverse Reactions of Sulfonamides

Associated with increased skin sensitivity to sunlight.
Long-term use may lead to blood issues, increasing infection risk, slow healing, and gum bleeding.

Rifampicin

Used to manage various mycobacterial and gram-positive bacterial infections.
Critical in the multi-drug treatment of drug-susceptible TB.
Common regimen combines Rifampin with Isoniazid, Ethambutol, and Pyrazinamide for the first two months.

Antifungal Agents

Fungal infections can involve skin, mucosa, or lead to systemic infections.
Polyene antibiotics, like Amphotericin B, are potent against systemic fungal infections.

Nystatin

Primarily treats candidal infections in mucosal areas and skin.
Available forms include aqueous suspension, vaginal tablets, creams, and oral tablets.
Dosage involves oral suspension, typically swished and held before swallowing for maximum efficacy.
Important to continue treatment for a minimum of two days post-symptom resolution to prevent recurrence.

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Test your knowledge on antimicrobial agents, including vancomycin, a tricyclic glycopeptide antibiotic used to treat bacterial infections caused by gram positive bacteria. Learn about its mechanism of action and uses.