Adverse effects of rifampin.

Rifampin has proved to be a valuable antibiotic with relatively few major adverse effects. Its toxicity is predominantly hepatic and immunoallergic in character. While hepatic toxicity is dose related and has been observed mainly in patients with underlying liver disease, the immunoallergic effects are usually associated with intermittent or prolonged therapy. These immunoallergic effects may be minor (a cutaneous, gastrointestinal, or influenzalike syndrome) or major (hemolytic anemia, shock, or acute renal failure).