Antibiotics 3 Flashcards
Mycobacteria
-slow growth
-low permeability
-lipid rich mycobacterial cell enevelope (waxy coat)
-resistant to drying and disinfectant
-bioactive - active and suppression of immune system
Antimycobacterial Drugs
resistant to most antibiotics
-slow growth
-lipid-rich cell wall
-intracellular
TM of tuberculosis
-isoniazid: inh mycobacterial cell wall synthesis
-ethanmbutol: inh mycobacterial cell wall synthesis
-rifampin: inh RNA synthesis
Fungal Infection
opportunistic pathogen
-surgery, TM of cancer, organ transplant, HIV, antibiotics overuse
common fungal pathogen - mycosis, dermatophyte, aflatoxin structural similarity to mammalian cells
-challenge for selective toxicity
Amphotericin B
bactericidal
* Binds to ergosterol and increase cell wall permeability
Azole
found in anti-dandruff
* Inhibit ergosterol synthesis by blocking fungal CYP450
Echinocandins
Inhibit fungal glucan synthesis
Antifungal Agents
- Polyene
- amphotericin B (natamycin); binds to ergosterol and increase cell wall permeability
- Pyrimidines
- flucytosine; thymidine synthesis inhibitors
- sig. resistance
- Azoles
- ketocon-; flucon-; micon- etc. ; ergosterol synthesis inhibitor
- CYP3A4 inhibitior
- Echinocandins (-fungins)
- caspo-, mica-, anidula-
- glucan synthesis (essential for intact fungal cell wall) inhibitor
Antiviral Drugs
- Virus
- intracellular
- replication depends on synthetic processes of host cell
Topical Antiviral Options for HSV
- Idoxuridine (nucleoside analogue)
- sig. corneal toxicity & poor ocular bioavailability
- Vidarabine (nucleoside analogue)
- limited accessibility, alternative for trifluridine hypersensitivity
- Trifluridine (thymidine synthetase inhibitor)
- drug of topical choice for HSV, less use than oral
- topical side effects common but generally well tolerated
Oral Antiviral Options for HSV
- Acyclovir (DNA polymerase inhibitor)
- highly selective
- topical formulation not available in US
- oral formulation for both prophylactic and
therapeutic use
□ require higher dosage for HZV - well tolerated
- Valacyclovir - prodrug of acyclovir w. improved
bioavailability & longer t1/2 - Famciclovir - prodrug of penciclovir (long t1/2)
- Gancyclorvir (available as topical gel)