Malaise isoniazid

Liver damage usually appears 1-2 months after the start of therapy. In children, raised liver enzymes are common during the first few months of treatment, but withdrawal is seldom necessary. A careful watch should be kept for early symptoms of isoniazid-induced hepatitis, such as malaise, fatigue, nausea, and epigastric distress. The dangers of continuing isoniazid after the onset of symptoms of toxicity have been highlighted (30). The earhest symptoms of isoniazid toxicity should be clearly described to the patient, particularly to hepatitis B carriers, who may be more susceptible to hepatotoxicity (26). 

Liver damage is the most common adverse effect of pyrazinamide (6). It varies from asymptomatic alteration of hver function detectable only by laboratory tests, through a mild syndrome characterized by fever, anorexia, malaise, hver tenderness, hepatomegaly, and splenomegaly, to more serious reactions with clinical jaundice, and finally the rare form with progressive acute yellow atrophy and death. As most patients take a combined regimen of pjrazinamide with isoniazid and rifampicin, it is difficult to determine which of the three drugs causes the hepatotoxicity it could be due to a combined effect (7). As with isoniazid and rifampicin, hepatic function should initially be monitored every few weeks. 

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