antimicrobial therapy (without cell wall inhibitors)

What is the mechanism of action for ß-lactams, Vancomycin, and bacitracin?

Inhibition of cell wall synthesis

What is the mechanism of action for Tetracyclines, Aminoglycosides, and Macrolides?

Inhibition of protein synthesis

What is the mechanism of action for Quinolones and Rifampicin?

Inhibition of RNA and DNA synthesis

What is the mechanism of action for Sulfonamides and Trimethoprim?

Inhibition of folate synthesis

What is the mechanism of action for Polymyxin, Polyenes, and Daptomycin?

Disruption of cell membrane function

How do Tetracyclines inhibit protein synthesis?

They compete with tRNA on the 30S ribosomal subunit

Are Tetracyclines bacteriostatic or bactericidal?

Bacteriostatic

What substances significantly decrease the oral absorption of tetracyclines?

Dairy products, Ca, Mg, Fe, & Al

Which tetracycline is excreted in bile and allowed in renal patients?

Doxycycline

What is a major use for tetracyclines in dentistry?

Management of periodontal disease

What is a common GIT side effect of tetracyclines?

Nausea, vomiting, epigastric pain

What is a common superinfection caused by tetracyclines?

Candida (vaginal or intestinal)

What are the effects of tetracyclines on teeth and bone?

Discoloration of teeth, dental hypoplasia, and bone deformities

Why are tetracyclines contraindicated in pregnancy?

Teratogenicity (bone and teeth abnormalities in fetus)

What syndrome is associated with expired tetracyclines?

Fanconi syndrome

How do Aminoglycosides inhibit protein synthesis?

Bind to 30S ribosomal subunits, causing misreading of mRNA

Are Aminoglycosides bacteriostatic or bactericidal?

Bactericidal

Are aminoglycosides well-absorbed orally?

No, they are polar compounds and must be given parenterally for systemic effect

What is a common oral use for Neomycin?

To sterilize the gut before GIT operations or in hepatic coma

What is the main adverse effect of Aminoglycosides on the 8th cranial nerve?

Ototoxicity (auditory and vestibular), which can be irreversible

What is a major adverse effect of Aminoglycosides on the kidneys?

Nephrotoxicity

What is the mechanism of macrolides (e.g., Erythromycin)?

Bind irreversibly to the 50S ribosomal subunit, inihibiting the translocation step

Is Erythromycin stable in acid?

No, it must be given as enteric-coated tablets

What is a major therapeutic use for Erythromycin in dentistry?

Second choice to penicillin for dental infections in allergic patients

What is a characteristic adverse effect of Erythromycin?

Cholestatic jaundice

Which macrolide is effective against H. influenzae and has a longer duration than erythromycin?

Clarithromycin

Which macrolide has a long duration (once daily) and is preferred for chlamydia infections?

Azithromycin

How does Chloramphenicol work?

Binds to 50S ribosomal subunit, inhibiting transpeptidation

What is the most serious, idiosyncratic, non-dose-related adverse effect of Chloramphenicol?

Fatal aplastic anemia

What is the reversible, dose-related adverse effect of Chloramphenicol?

Reversible anemia

What is "Gray baby syndrome" caused by?

Accumulation of chloramphenicol in premature neonates

Why is Chloramphenicol a risk for drug interactions?

It inhibits hepatic microsomal enzymes (HME)

What is the principal use for Clindamycin?

Anaerobic infections (especially Bacteroides fragilis)

What is a major adverse effect of Clindamycin?

Pseudomembranous colitis

What is the treatment for pseudomembranous colitis?

Oral metronidazole or vancomycin

What is the mechanism of action for Quinolones (e.g., ciprofloxacin)?

Inhibition of DNA gyrase enzyme, preventing DNA supercoiling

Are quinolones bacteriostatic or bactericidal?

Bactericidal

Which generation of quinolones includes Ciprofloxacin and Ofloxacin?

Second generation

Which generation of quinolones added anaerobic activity?

Fourth generation (e.g., trovafloxacin)

What is a major adverse effect of quinolones on cartilage?

Damage to growing cartilage (arthropathy)

Why are quinolones contraindicated in pregnancy, lactation, and patients under 18?

Risk of arthropathy

What is the mechanism of action for Rifampicin?

Inhibition of DNA-dependent RNA polymerase

What is a characteristic, harmless side effect of Rifampicin?

Red discoloration of urine and all excreta

Why does Rifampicin have many drug interactions?

It is a potent hepatic microsomal enzyme (HME) inducer

What is the primary use for Rifampicin?

Treatment of TB and leprosy

What is the mechanism of action for Sulfonamides?

They are bacteriostatic

What is a major adverse effect of Sulfonamides on the kidney?

Crystalluria

How can sulfonamide-induced crystalluria be avoided?

Plenty of fluids and alkalinization of urine

Why are Sulfonamides contraindicated in pregnancy and infants?

Displace bilirubin, causing kernicterus

What is Co-Trimoxazole?

A combination of sulfamethoxazole and trimethoprim

How does Co-Trimoxazole work?

It produces a sequential block in folic acid synthesis, making it bactericidal

What is the mechanism of Metronidazole?

It is reduced to an active metabolite that binds to DNA and inhibits nucleic acid synthesis

What is a common dental use for Metronidazole?

Acute ulcerative gingivitis and dental abscess

What is a characteristic adverse effect of Metronidazole?

Metallic taste

What reaction occurs if alcohol is taken with Metronidazole?

Disulfiram-like reaction

Why is combination drug therapy a "must" for tuberculosis?

To prevent the development of resistance

What are the four "first-line" drugs for TB?

Isoniazid (INH), Rifampin, Pyrazinamide, Ethambutol

What is the mechanism of Isoniazid (INH)?

It is a prodrug that inhibits the synthesis of mycolic acid (cell wall)

What is the most serious adverse effect of INH?

Hepatitis

What common adverse effect of INH is caused by pyridoxine deficiency?

Peripheral neuropathy

How is INH-induced peripheral neuropathy prevented?

Supplementation with pyridoxine (vitamin B6)

What is the mechanism of action for Ethambutol?

Inhibits arabinosyl transferase, an enzyme for mycobacterial cell wall synthesis

What is the most important adverse effect of Ethambutol?

Optic neuritis (loss of red-green color discrimination)

What is a common adverse effect of Pyrazinamide?

Uric acid retention (can precipitate a gouty attack)

What is DOT (Directly Observed Therapy) in TB treatment?

Patients take medications while being watched by a healthcare worker to improve cure rates and decrease resistance

What are examples of second-line anti-TB drugs?

Aminoglycosides (Streptomycin), Fluoroquinolones

What is the mechanism of action for Amphotericin B?

Binds to ergosterol in the fungal cell membrane, forming pores

What are the immediate adverse effects of Amphotericin B infusion?

Fever, chills, vomiting, hypotension

What is the major delayed toxicity of Amphotericin B?

Nephrotoxicity

What is the mechanism of action for Azole antifungals (e.g., Ketoconazole)?

Inhibit fungal cytochrome P450, reducing ergosterol synthesis

Which systemic azole is known for causing adrenal/gonadal hormone dysfunction?

Ketoconazole

What is the mechanism of action for Nystatin?

Same as Amphotericin B (binds to ergosterol)

What is the primary use for oral Nystatin?

Topical treatment of oral moniliasis (Candida)