DƯỢC LÍ Goodman & Gilman's The Pharmacological Basis of Therapeutics 12th, 2010

Table 64–5
Antiviral Agents for Ophthalmic Use
GENERIC NAME (TRADE NAME) ROUTE OF ADMINISTRATION OCULAR TOXICITY INDICATIONS FOR USE
Trifluridine (VIROPTIC, others) Topical (1% solution) PK, H Herpes simplex keratitis and
keratoconjunctivitis
Acyclovir (ZOVIRAX) Oral, intravenous (200-mg capsules, Herpes zoster ophthalmicus a
400- and 800-mg tablets) Herpes simplex iridocyclitis
Valacyclovir (VALTREX) Oral (500- and 1000-mg tablets) Herpes simplex keratitis a
Herpes zoster ophthalmicus a
Famciclovir (FAMVIR) Oral (125-, 250-, and 500-mg tablets) Herpes simplex keratitis a
Herpes zoster ophthalmicus a
Foscarnet (FOSCAVIR) Intravenous Cytomegalovirus retinitis
Intravitreal a
Ganciclovir
Cytomegalovirus retinitis
(CYTOVENE)
Intravenous, oral
(VITRASERT)
Intravitreal implant
Valganciclovir (VALCYTE) Oral Cytomegalovirus retinitis
Cidofovir (VISTIDE) Intravenous Cytomegalovirus retinitis
a
Off-label use. For additional details, see Chapter 58. PK, punctate keratopathy; H, hypersensitivity.
Antifungal Agents
General Considerations. The only currently available topical
ophthalmic antifungal preparation is a polyene,
natamycin (NATACYN), which has the following structure:
Other antifungal agents may be extemporaneously
compounded for topical, subconjunctival, or
intravitreal routes of administration (Table 64–6). The
pharmacology and structures of available antifungal
agents are given in Chapter 57.
Therapeutic Uses. As with systemic fungal infections, the
incidence of ophthalmic fungal infections has risen with
the growing number of immunocompromised hosts.
Ophthalmic indications for antifungal medications
include fungal keratitis, scleritis, endophthalmitis,
mucormycosis, and canaliculitis. Risk factors for fungal
keratitis include trauma, chronic ocular surface disease,
contact lens wear, and immunosuppression (including
topical steroid use).
In 2005-2006, there was a worldwide epidemic of Fusarium
fungal keratitis related to a specific contact lens solution, which
resolved when it was removed from the market (Chang et al., 2007).
When fungal infection is suspected, samples of the affected tissues are
obtained for smears, cultures, and sensitivities, and this information is
used to guide drug selection.
Antiprotozoal Agents
General Considerations. Parasitic infections involving the
eye usually manifest themselves as a form of uveitis,
an inflammatory process of either the anterior or posterior
segments and, less commonly, as conjunctivitis,
keratitis, and retinitis.
Therapeutic Uses. In the U.S., the most commonly encountered
protozoal infections include Acanthamoeba and
Toxoplasma gondii. In contact lens wearers who develop
keratitis, physicians should be highly suspicious of the
presence of Acanthamoeba (McCulley et al., 2000).
Additional risk factors for Acanthamoeba keratitis include poor
contact lens hygiene, wearing contact lenses in a pool or hot tub, and
ocular trauma. Treatment usually consists of a combination of topical
agents. The aromatic diamidines (i.e., propamidine isethionate in both
topical aqueous and ointment forms [BROLENE]) have been used successfully
to treat this relatively resistant infectious keratitis (Hargrave
et al., 1999), although it is not available in the U.S. The cationic