antibioticsbooks

158 PART 3 Antimycobacterial Drugs
neuritis and, rarely, seizures. Drug-induced lupus
can also occur; this abates with the cessation of
therapy. Like other tuberculosis medications, hepatotoxicity
is also possible. Hypersensitivity can be
seen, most commonly as rash or drug fever.
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Important Facts
• Isoniazid is a drug of choice for the treatment
of latent tuberculosis. It can be given as monotherapy
for latent disease because the burden
of organisms is much lower than in active
tuberculosis, where resistance can develop to
monotherapy.
• Isoniazid is a classic example of a drug with
variable pharmacogenomic metabolism. “Rapid
acetylators” of isoniazid metabolize it more
quickly than “slow acetylators,” but the clinical
significance of this is unknown. Genetic testing
is not routinely performed before starting
isoniazid.
• Isoniazid is bactericidal against growing mycobacteria,
but bacteriostatic against dormant
mycobacteria.
• Patients should be advised not to drink alcohol
while taking isoniazid. This has nothing to do
with the common myth that alcohol decreases
antibiotic effectiveness; it is to prevent an additive
risk of hepatotoxicity.
What It’s Good For
Isoniazid is a drug of choice for both active and latent
tuberculosis. For treatment of active tuberculosis,
it must be combined with other medications. The
combination of isoniazid and rifampin is recommended
for the consolidation phase of non -MDR-TB.