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Which patients are recommended to receive prophylactic antibiotics before dental procedures?
Which patients are recommended to receive prophylactic antibiotics before dental procedures?
What is the drug of choice for anaerobic gum infections?
What is the drug of choice for anaerobic gum infections?
What is a significant side effect of clindamycin that should be considered?
What is a significant side effect of clindamycin that should be considered?
What type of antifungal agent is Nystatin and its main indication?
What type of antifungal agent is Nystatin and its main indication?
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What is the recommended duration for antibiotic treatment of most acute dental infections?
What is the recommended duration for antibiotic treatment of most acute dental infections?
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Which antibiotics specifically inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit?
Which antibiotics specifically inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit?
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What is a known adverse effect of tetracycline administration?
What is a known adverse effect of tetracycline administration?
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Which of these antibiotics is considered bactericidal at higher concentrations?
Which of these antibiotics is considered bactericidal at higher concentrations?
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What is one of the therapeutic uses of tetracyclines?
What is one of the therapeutic uses of tetracyclines?
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What is the mechanism of action of chloramphenicol?
What is the mechanism of action of chloramphenicol?
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Which statement is true about the use of tetracyclines in acute orodental infections?
Which statement is true about the use of tetracyclines in acute orodental infections?
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Which nutritional substances should be avoided when taking tetracyclines?
Which nutritional substances should be avoided when taking tetracyclines?
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What is the mechanism by which aminoglycosides exert their effect on bacteria?
What is the mechanism by which aminoglycosides exert their effect on bacteria?
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What is a key characteristic of aminoglycosides regarding their absorption?
What is a key characteristic of aminoglycosides regarding their absorption?
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What adverse effect is most commonly associated with aminoglycosides?
What adverse effect is most commonly associated with aminoglycosides?
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In which situation is the risk of ototoxicity from aminoglycosides increased?
In which situation is the risk of ototoxicity from aminoglycosides increased?
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What adjustment should be made for patients with renal insufficiency receiving aminoglycosides?
What adjustment should be made for patients with renal insufficiency receiving aminoglycosides?
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What class of bacteria are aminoglycosides particularly effective against?
What class of bacteria are aminoglycosides particularly effective against?
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Which of the following is a contraindication for the use of aminoglycosides?
Which of the following is a contraindication for the use of aminoglycosides?
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How are aminoglycosides primarily eliminated from the body?
How are aminoglycosides primarily eliminated from the body?
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What serious complication can arise from fetal exposure to aminoglycosides?
What serious complication can arise from fetal exposure to aminoglycosides?
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What is the primary therapeutic use of linezolid?
What is the primary therapeutic use of linezolid?
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What is a key characteristic of Clindamycin as an antibiotic?
What is a key characteristic of Clindamycin as an antibiotic?
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Which macrolide has the longest half-life?
Which macrolide has the longest half-life?
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In which scenario would Clindamycin be preferred over penicillin?
In which scenario would Clindamycin be preferred over penicillin?
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Which of the following is a common side effect of Clindamycin?
Which of the following is a common side effect of Clindamycin?
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Which of the following is NOT a therapeutic use of macrolides?
Which of the following is NOT a therapeutic use of macrolides?
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What is a common adverse reaction associated with macrolides?
What is a common adverse reaction associated with macrolides?
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What is a contraindication for using Clindamycin?
What is a contraindication for using Clindamycin?
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What type of infections are fluoroquinolones particularly effective against?
What type of infections are fluoroquinolones particularly effective against?
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Which macrolide does NOT require dose adjustment in renal patients?
Which macrolide does NOT require dose adjustment in renal patients?
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Which fluoroquinolone is known as a respiratory fluoroquinolone?
Which fluoroquinolone is known as a respiratory fluoroquinolone?
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Which of the following is a characteristic of azithromycin?
Which of the following is a characteristic of azithromycin?
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What is a limitation of using Moxifloxacin as a first-line treatment?
What is a limitation of using Moxifloxacin as a first-line treatment?
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Why is erythromycin considered a secondary choice in treatment?
Why is erythromycin considered a secondary choice in treatment?
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Which bacteria are macrolides most effective against?
Which bacteria are macrolides most effective against?
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Which fluoroquinolone may be combined with metronidazole for refractory mixed infections?
Which fluoroquinolone may be combined with metronidazole for refractory mixed infections?
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What is the mechanism of action for nucleic acid synthesis inhibitors?
What is the mechanism of action for nucleic acid synthesis inhibitors?
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What gastrointestinal side effects are relatively less common with azithromycin and clarithromycin?
What gastrointestinal side effects are relatively less common with azithromycin and clarithromycin?
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What type of antibiotic spectrum does macrolides have?
What type of antibiotic spectrum does macrolides have?
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Which adverse effect is associated with fluoroquinolones?
Which adverse effect is associated with fluoroquinolones?
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Study Notes
Protein Synthesis Inhibitors
- This antibacterial group includes aminoglycosides, macrolides, tetracyclines, lincosamides, chloramphenicol, and linezolid.
30S Ribosomal Subunit Inhibitors
- Aminoglycosides
- Tetracyclines
50S Ribosomal Subunit Inhibitors
- Chloramphenicol
- Macrolides
Chloramphenicol
- Bacteriostatic broad-spectrum antibiotic
- Bactericidal at higher concentrations
- Mechanism: Binds reversibly to 50S ribosomal subunit, inhibiting bacterial protein synthesis.
- Clinical uses: Typhoid fever (alternative: ciprofloxacin), topical antimicrobial agent.
- Adverse reactions: Gastrointestinal disturbances, aplastic anemia (rare), gray baby syndrome, cyanosis, super-infection.
Tetracyclines
- Tetracycline, Doxycycline, Demeclocycline, Minocycline, oxytetracycline
- Mechanism: Binds to 30S ribosomal subunit, inhibiting bacterial protein synthesis.
- Therapeutic uses: Concentrated in gingival fluid, used to eradicate resistant bacteria in chronic periodontal disease. Limited usefulness in acute orodental infections, often used as a second choice after penicillin, erythromycin, and cephalosporins. Other uses include eradication of H. pylori, preventing malaria, treating amebiasis, treating acne.
- Adverse reactions: Heartburn, nausea, vomiting, alteration in the normal flora (oral candidiasis), colitis (C. difficile), discoloration and hypoplasia of teeth (in young children and during pregnancy).
Macrolides
- Erythromycin, Clarithromycin, Azithromycin
- Spectrum: Bacteriostatic, narrow-spectrum antibiotics, effective against gram-positive cocci (streptococci, gram-positive bacilli), few gram-negative bacilli, and some atypical organisms, but not effective against anaerobes.
- Kinetics: Erythromycin absorption affected by food, Clarithromycin and Azithromycin not affected. Wide distribution, concentrated in macrophages (especially azithromycin).
- Half-lives: Erythromycin (6 hours), Clarithromycin (12 hours), Azithromycin (>24 hours)
- Dose adjustment: needed for renal patients with Clarithromycin.
- Adverse reactions: Epigastric distress, nausea, vomiting, diarrhea, cholestatic hepatitis.
Aminoglycosides
- Protein synthesis inhibitors
- Mechanism: Enhance bacterial protein synthesis by cell wall synthesis inhibitors
- Bactericidal agent
- Pharmacokinetics: Poor oral absorption; given orally for local effect in GIT, adjust dosage for renal insufficiency.
- Adverse reactions: Ototoxicity (may be irreversible) and nephrotoxicity (reversible); more common in elderly patients, particularly with the presence of other ototoxic and nephrotoxic drugs (i.e. loop diuretics).
Lincosamides
- Clindamycin
- Broad-spectrum bacteriostatic antibiotic that covers both aerobic and anaerobic pathogens.
- May be prescribed in persistent infections, an excellent choice in penicillin-allergy cases.
- Adverse reactions: Vomiting, nausea, diarrhea, exanthem, jaundice, hepatitis, neutropenia, eosinophilia, agranulocytosis, blood platelet count change, pseudomembranous colitis.
Fluoroquinolones
- DNA synthesis inhibitors
- Mechanism: Inhibit DNA synthesis by inhibiting DNA gyrase.
- Categories are 1st, 2nd, 3rd, 4th generations.
- 2nd generation: Anti-pseudomonal fluoroquinolones (e.g., ciprofloxacin)
- 3rd generation: Respiratory fluoroquinolones (e.g., levofloxacin)
- 4th generation: Moxifloxacin
- Therapeutic uses: Bactericidal, used for orodental infections caused by gram-negative bacilli resistant to other antibiotics. Gatifloxacin (3rd generation) is active against Gram-positive bacteria and anaerobes. Ciprofloxacin may be combined with metronidazole in refractory or mixed infections. Moxifloxacin considered a good choice for odontogenic and periodontal infections.
- Adverse reactions: Central nervous system effects (headache, dizziness, insomnia, seizures), gastrointestinal issues (nausea, diarrhea, abnormal liver function), skin reactions (rashes, photosensitivity), musculoskeletal problems (tendonitis, tendon rupture)
- Not recommended in children or during pregnancy due to cartilage erosion.
Metronidazole
- Effective against anaerobic gram-negative and gram-positive bacteria.
- Treatment of choice for Clostridium difficle (pseudomembranous colitis). Antiprotozoal agent.
- Adverse reactions: Gastrointestinal upsets, metallic taste, seizures, and cumulative peripheral neuropathy (uncommon, but serious, avoid repeated courses).
- Drug interactions: Should be used cautiously with drugs which prolong QT interval (clarithromycin, azithromycin), inhibits cytochrome P450, and thus potentiates anticoagulant effects of warfarin.
Antifungal Drugs
- Classified as systemic or topical agents.
- Nystatin: Highly toxic, used topically (effective against Candida).
- Griseofulvin: Isolated from Penicillium griseofulvium; active against Microsporum (superficial infection/dermatophytosis).
- Amphotericin B: Poorly absorbed from the GIT and topically; widely distrubuted in tissues post IV administration. About 60% metabolized in the liver and excretion is slow (urine and bile).
- Indications: Oral candidiasis, topical treatment for oral, vaginal and cutaneous candidiasis, hospital treatment for severe systemic fungal infections.
- Adverse reactions: nausea, vomiting, headache, fever, breathlessness, thrombophlebitis (in IV administration), dose-related nephrotoxicity, and anemia (in prolonged use)..
Antiviral Drugs
- Oral viral infections (herpes simplex virus types 1 and 2, Epstein-Barr virus, varicella-zoster virus, Coxsackie virus, human papilloma virus, human immunodeficiency virus).
- Classification:
- Drugs for herpes (Acyclovir, Ganciclovir)
- Drugs for influenza (Amantadine, Zanamivir)
- Drugs for HBV and HCV (Interferon, Lamivudine, Ribavirin)
- Drugs for HIV (Zidovudine, Didanosine)
- Acyclovir: Competitive substrate for DNA polymerase; inhibits DNA polymerase, incorporated into viral DNA, premature chain termination.
- Route of administration: Oral, intravenous (IV), topical.
- Indications: Prophylaxis against herpes infections in AIDS and other immunosuppressed patients; treatment of herpes simplex virus infection; treatment of varicella (chickenpox) and herpes zoster (shingles).
- Adverse effects: Few side effects (i.e., nausea, diarrhea, headache, nephrotoxicity, hepatoxicity)
Dental Implications of Chemotherapy Agents
- Treatment of acute dental infections.
- Prophylactic use for dental procedures: Patients with congenital or history of rheumatic fever, patients with transplanted organs, patients with uncontrolled diabetes mellitus, patients with certain oro-facial traumatic wounds, and patients on immunosuppressant and/or corticosteroid therapy.
- Commonly prescribed antibiotics in dentistry: Penicillins (amoxicillin, amoxicillin and clavulanic acid), metronidazole.
- Azithromycin can be used in penicillin allergy cases as it is active against some oral anaerobes.
Ideal antibiotic duration
- ideal duration of antibiotic treatment is shortest cycle; most acute infections are resolved in 3-7 days.
Antimicrobials for dental practice
- Antimicrobials active against gram-positive cocci and oral anaerobes: amoxicillin; safe & bactericidal; chlorhexidine 0.2% also used as adjuvant to reduce bacteremia following dental extractions.
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Description
Explore the various classes of protein synthesis inhibitors, including aminoglycosides, tetracyclines, macrolides, and chloramphenicol. This quiz covers mechanisms, clinical uses, and adverse reactions of these antibacterial agents. Test your knowledge on how these antibiotics function at the ribosomal level.
