Adverse Effects and Toxicity of Antituberculosis Drugs

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.