Antibacterial Agents - Bug Busters
| Class | MoA | Spectrum | Uses | AEs (Ophth/Sys) |
|---|---|---|---|---|
| FQs | DNA gyrase inh. | Broad G+/G- | Conj/Keratitis, surg. proph. | Cipro ppts, tendinopathy (sys) 📌Tendons groan |
| AGs | 30S ribo. inh. | G- (Pseudo) | Conj/Keratitis (fort. Tobra 9-14 mg/mL) | Corneal tox, ototoxicity (sys) |
| Macrolides | 50S ribo. inh. | G+, Chlam. | Bleph/Conj (Azithro, Erythro) | Irritation |
| Tetracyclines | 30S ribo. inh. | Broad, Chlam | Bleph (Doxy), trachoma | Photosens., teeth (kids <8) |
| Chloramph. | 50S ribo. inh. | Broad | Conj/Keratitis | Aplastic anemia (sys), optic neuritis |
| Sulfonamides | Folate inh. | G+/G-, Chlam | Conj. (Sulfacetamide) | SJS, allergy |
| Polymyxin B | Cell memb. disrupt. | G- (Pseudo) | Combo: Conj/Keratitis | Irritation |
| Bacitracin | Cell wall inh. | G+ | Oint: Bleph/Conj (combo) | Allergic contact derm. |
Antifungal Agents - Fungal Foes
| Class | Examples (Dose) | MoA | Spectrum | Key Ophthalmic Uses | Routes |
|---|---|---|---|---|---|
| Polyenes | Natamycin (5% susp), Amphotericin B (topical 0.1-0.5%) | Binds ergosterol → pore formation | Broad (Filamentous > Yeasts) | Fungal keratitis, endophthalmitis | Top, IC, IVit, Systemic |
| Azoles | Voriconazole (topical 1%), Fluconazole, Ketoconazole | Inhibits ergosterol synthesis | Broad (Yeasts & Molds) | Fungal keratitis, endophthalmitis | Top, Systemic, IVit |
| Echinocandins | Caspofungin | Inhibits $\beta$-(1,3)-D-glucan synthesis | Candida, Aspergillus | Severe/resistant keratitis | Systemic, IVit (off-label) |
Antiviral Agents - Viral Vanquishers
| Virus Group | Drugs (Examples) | Mechanism (Simplified) | Key Ophthalmic Uses | Key Side Effects (Notable) |
|---|---|---|---|---|
| HSV, VZV | Trifluridine, Acyclovir, Valacyclovir, Famciclovir, Ganciclovir (topical/systemic/intravitreal implant) | Inhibit viral DNA synthesis/polymerase | Herpetic keratitis, uveitis, ARN, PORN | Corneal toxicity (Trifluridine), Nephrotoxicity (Acyclovir), Myelosuppression (Ganciclovir) |
| CMV | Ganciclovir (systemic/intravitreal implant 1 µg/hr), Valganciclovir, Foscarnet, Cidofovir | Inhibit viral DNA polymerase (Ganciclovir, Cidofovir); Direct polymerase inhibition (Foscarnet) | CMV retinitis | Myelosuppression (Ganciclovir/Valganciclovir), Nephrotoxicity (Foscarnet, Cidofovir) |
Antiparasitic & Antiseptic Agents - Tiny Terrors Tackled
- Antiparasitics:
- Acanthamoeba keratitis: PHMB 0.02-0.06%, Chlorhexidine 0.02-0.2% (membrane disruption); Propamidine 0.1% (DNA inhibition); Miltefosine (oral, resistant).
- Toxoplasmosis (systemic): Pyrimethamine, Sulfadiazine, Clindamycin.
- Antiseptics:
- Povidone-iodine (free iodine): Skin prep 5-10%; Conjunctival irrigation 0.5-1.25%; Neonatal prophylaxis 2.5%.
⭐ Acanthamoeba keratitis: often prolonged, requires combination therapy (biguanide e.g., PHMB/Chlorhexidine + diamidine e.g., Propamidine).
High‑Yield Points - ⚡ Biggest Takeaways
- Bacterial Keratitis: Treat with fortified cefazolin + tobramycin.
- Fungal Keratitis: Natamycin for Fusarium; Amphotericin B for Candida. Voriconazole is an alternative.
- Herpetic Keratitis: Use topical ganciclovir/trifluridine. Oral acyclovir for HZO or prophylaxis.
- Acanthamoeba Keratitis: Requires PHMB/Chlorhexidine; treatment is often prolonged.
- Endophthalmitis: Administer intravitreal vancomycin + ceftazidime/amikacin.
- Trachoma: Managed with systemic azithromycin (SAFE strategy).
- Bacterial Conjunctivitis: Topical fluoroquinolones or polymyxin B-trimethoprim are common choices.
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