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

Therapeutic Uses. Tenofovir is approved for treatment of HBV
infection in adults at a dose of 300 mg once daily without regard to
food. In HBeAg-negative patients, tenofovir suppressed HBV DNA
to <400 copies/mL in 93% of subjects at 48 weeks, compared to 63%
for adefovir. Tenofovir resistance was not evident over 48 weeks of
treatment. Due to the safety, efficacy, and resistance profile of tenofovir,
it will likely supersede most adefovir use for the treatment of
chronic HBV infection.
The tenofovir dose should be adjusted for impaired renal
function: For Cl cr
of 30-49 mL/minute, 300 mg every 48 hours;
10-29 mL/minute, 300 mg every 72-96 hours. During hemodialysis
the dose is 300 mg every 7 days or after 12 hours of dialysis.
Clevudine
Clevudine is a nucleoside analog with potent activity against HBV.
The oral drug is approved for use in South Korea and the Philippines.
However the drug caused myopathy in large Phase 3 clinical trials,
casting doubt on its future approval in the U.S.
OTHER AGENTS
Imiquimod
Imiquimod [1-(2-methylpropyl)-1H-imidazo[4,5-c]quinolin-4
amine] is a novel immunomodulatory agent that is
effective for topical treatment of condylomata acuminata,
molluscum contagiosum, and certain other dermatologic
conditions associated with DNA virus infections
(Skinner, 2003). It lacks direct antiviral or antiproliferative
effects in vitro but rather induces cytokines and
chemokines with antiviral and immunomodulating
effects.
Imiquimod shows antiviral activity in animal models after
systemic or topical administration. When applied topically as a 5%
cream to genital warts in humans, it induces local IFN-α, -β, and -γ
and TNFα responses and causes reductions in viral load and wart
size. When applied topically (three times weekly for up to 16 weeks),
imiquimod cream is associated with complete clearance of treated
genital and perianal warts in ~50% of patients, with response rates
higher in women than in men (Skinner, 2003; Wiley et al., 2002).
The median time to clearance is 8-10 weeks; relapses are not uncommon.
Application is associated with local erythema in ~20% of
patients, excoriation/flaking in 18-26%, itching in 10-20%, burning
in 5-12%, and less often, erosions or ulcerations.
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CHAPTER 58
ANTIVIRAL AGENTS (NONRETROVIRAL)