Does Isoniazid Reduce Side Effects of Intravesical Bacillus Calmette-Guerin Therapy in Superficial Bladder Cancer? Interim Results of European Organization for Research and Treatment of Cancer Protocol 30911

Prophylactic administration of isoniazid during BCG instillations provides no decrease in any known side effect of BCG. In contrast, transient liver function disturbances are encountered slightly more frequently when isoniazid is administered. The use of prophylactic isoniazid in patients treated with BCG is not recommended.