Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Immucyst (Bacillus-calmette-guerin-bcg).

Handling of urine: Because BCG contains live mycobacteria urine may also contain the live bacteria. You should use appropriate infection control procedures to protect others from infection. This is especially true if you are living with someone who has reduced immunity (e.g. on chemotherapy).

For up to 6 hours after therapy, you should urinate while sitting to minimize the risk of splashing urine. Also, you should disinfect with equal volume of household bleach for 15 minutes before flushing.

Systemic BCG reaction: Although rare, a systemic granulomatous illness have been reported subsequent to exposure to BCG. Based on past reports, "systemic BCG reaction" may have any of the following signs: fever ≥39.5°C for 12 hours; fever ≥38.5°C for 48 hours; cough/pneumonitis; liver dysfunction; or the classical signs of severe infection such as Low Blood Pressure, difficulty breathing.  Although rare, the reaction is much more likely to occur if BCG  is administered within 14 days of biopsy, TUR, or traumatic bladder catheterization (associated with hematuria).

Pregnancy: BCG has not been studied for use by pregnant women. It is best to use birth control while being treated with Immucyst (Bacillus-calmette-guerin-bcg). Tell your doctor immediately if you become pregnant during treatment. BCG should be used by pregnant women only if the benefits outweigh the risks.

Breast-feeding: It is not known whether BCG passes into breast milk. Women should not breast-feed while receiving BCG treatment due to risk of potential harm to the infant.