Midterm 1 Flashcards
Acyclovir (Zovirax)
Oral. Category B. Inhibits viral DNA replication via viral thymidine kinase. Used for acute tx of HSV keratitis and VZV. Few AE, may cause GI upset and HAs.
Dosing: For HSV: 400mg 5x/day for 7-14 days
For VZV: 800mg 5x/day for 7-14 days. CHEAP! good to use if pt doesn’t like drops
Valacyclovir (Valtrex)
Oral. Category B. An acyclovir pro-drug with greater GI absorption. For acute tx of VZV and HSV.
Dosing: 500 mg tid for HSV. 1g tid for VZV. OR 500mg qd for 5 years for recurrent HSV. Cheap, has 3-5x bioavailability of acyclovir.
Famciclovir (Famvir)
Oral. Category B. Inhibits viral DNA replication via viral thymidine kinase. Pro-drug of penciclovir. For acute tx of VZV and HSV.
Dosing: 250 mg tid for HSV, 500 mg tid for VZV OR 250 mg bid for 12 mos to suppress recurrent HSV. More expensive
Penciclovir (Denavir)
Topical. Category C. Inhibits viral DNA replication via viral thymidine kinase. For recurrent orolabial herpes (cold sores). Cream.
Trifluridine (Viroptic)
Topical. Category C. Inhibits viral AND HOST DNA synthesis via the enzyme thymidine synthetase. A thymidine analog gets incorporated into the DNA and prevents DNA replication. For recurrent HSV keratitis and stromal HSV. AE: SPK or SPEE, conj edema/hyperemia, delayed wound healing.
Dosing: 1 gt q2h x7 days; then q4-6h if pt is improving. Expensive
Ganciclovir (Zirgan)
Topical. Category C. Selectively targets virus infected cells only. Prodrug that is phosphorylated to active compound by HSV thymidine kinase. For recurrent HSV keratitis and stromal HSV. Also used off label for adenovirus and the tx of CMV retinitis.
Dosing: 1 gt 5x/day until ulcer heals then 1 gt tid x7 days. Equally effective as viroptic with less AE. Expensive, preferred topical tx.
Betadine (Providone Iodine)
Topical. Category C. Iodine based anti-septic that kills fungi, bacteria, and viruses. Used off label for adenovirus treatment also used as antiseptic in first aid kits and before cataract sx. Used in office. Stings eye, leaves a yellow stain
Zostavax
Vaccine for VZV, Boosts VZV-specific immunity via injection of live attenuated virus. For prevention of shingles.
Treatment for CMV Retinitis
Ganciclovir, Ziduvidine, Fosarnet, Cidovir. All taken orally or injected. Usually given by retninal specialist.
Natamycin (Natacyn)
Polyene. Topical suspension. Only topical drug FDA approved for use as an antifungal. Extremely broad spectrum. Increased cell membrane permeability, internal contents leak out leading to cell death. Fungicidal.
Amphotericin B
Antifungal. Polyene. Topical suspension. Increased cell membrane permeability, internal contents leak out leading to cell death. Fungicidal.
Flucytosine
Antifungal. Anti-metabolite. Impairs DNA synthesis. Turns into an antimetabolite in the cell. Considered fungistatic, stops growth of fungi but does not kill it.
Miconazole
Ketoconazole
Voriconazole
Itraconazole
Antifungal. Azoles. Block ergosterol synthesis needed for the cell membrane. Fungistatic first then fungicidal.
Propamidine Isethionate (Brolene) Hexamidine (Desmidine)
Anti-acanthamoeba. Diaminidines. Disruption of the cytoplasmic membrane causes increased permeability leading to a loss of the intracellular contents and death.
Polyhexamethylene Biguanide (PHMB)
Anti-acanthamoeba. Biguanide. The most common drug used. Disruption of the cytoplasmic membrane causes increased permeability leading to a loss of the intracellular contents and death.
Bacitracin
Antibiotic. Gram positive. Target the peptidoglycan bonds in the cell wall. Available in ointment. Mostly commonly rx’d for blepharitis.
Polysporin
Bacitracin and Polymixin B
Neosporin
Bacitracin and Polymixin B and Neomycin
Vancomycin
Antibiotic. Gram positive and MRSA. Targets the peptidoglycan bonds in the cell wall. Mainly given as an IV for MRSA and endoophthalmitis. Can be compounded for topical use and subconj injection. Used when other antibiotics are not effective, especially corneal ulcer. Dosing: 50mg/ml q30mins alternating with a gram negative drop for the first day. AE: ototoxicity, nephrotoxicity, red man syndrome.
Penicillin G and V
Natural penicillins. Gram positive, syphilis, gonorrhea. Inhibit the enzyme transpeptidase to prevent the formation of the peptidoglycan cell wall. Pen G available as IV, IM. PCN V available as oral. Rarely used because of resistance. Type 1 and 4 hypersensitivities common.
Ampicillin
Amoxicillin
Penicillins. Gram positive and negative. Inhibit the enzyme transpeptidase to prevent the formation of the peptidoglycan cell wall. Ampicillin available as oral. Amoxicillin available as oral and topical suspension. Indicated for deep infections, Dosing: 250 or 500mg tid x 5-14days. OR 500 or 875mg tid x5-14 days. Type 1 and 4 hypersensitivities common.
Augmentin
Amoxicillin and Clavulanic Acid.
Methicillin
Nafcillin
Cloxacillin
Dicloxacillin
Penicillinase resistant penicillins. Effective against staph. All have IV and oral formulations except methicillin which is just IV. Inhibit the enzyme transpeptidase to prevent the formation of the peptidoglycan cell wall. Rarely used by ODs. Type 1 or 4 hypersensitivities.
Cephalexin (Keflex)
Cephazolin
Cephalosporin. Gram positive. Cephalexin available in oral, cephazolin available as IV. Inhibit the enzyme transpeptidase to prevent the formation of the peptidoglycan cell wall.Cephalexin indicated for preseptal cellulitis, internal hordeolum. Dosing: 250-500 mg bid x 7-10 days. Contraindicated for PCN allergy