This chapter covers side and adverse effects associated to antituberculosis
treatment. Gastrointestinal side effects are usually the first to appear after the start of
treatment, with nausea and vomiting being the most common. Drug regimens for
multidrug resistant tuberculosis include drugs that very frequently produce side effects
and/or toxicity that sometimes require the definitive suspension of the drug. Almost all
patients undergoing drug treatment for MDR-TB experience some type of side effects
and/or toxicity that involve a modification of the drug regimen in up to 50% of the
cases. A problem associated to second-line drugs is that several of these drugs share
side effects and toxicities, which makes it difficult sometimes to determine which drug
is the culprit. It is extremely important to avoid as much as possible interruptions in
treatment due to side effects because this decreases the effectiveness of the regimen and
increases the risk of amplifying drug resistance. Peripheral neuropathy is more
common in patients that are already prone to it such as diabetics, alcoholics, pregnant
and malnourished patients. All antituberculosis injectable drugs are toxic to the eight
cranial nerve and can cause both vestibular (equilibrium) and cochlear (auditory)
damage. Hepatic toxicity is the most common adverse effect of antituberculosis
treatment and its severity can range from asymptomatic elevation of liver enzymes to
fulminant liver insufficiency with encephalopathy and high mortality. Although any
patient under treatment with antituberculosis drugs can develop hepatic toxicity,
patients with previous liver damage are at higher risk of this complication.
Keywords: Adverse, Ataxia, Creatinine, Effects, Enzymes, Hepatotoxicity,
Hypersensitivity, Liver, MDR-TB, Neuropathy, Renal failure, Stevens-Johnson, Toxicity,
Optic neuritis, Urticaria, Vestibular, Vertigo.
