When Do Heart Side Effects Occur?

The timing of chest pain symptoms from fluoropyrimidine chemotherapy depends on the type of chemotherapy (if it is given as an IV or as a pill) and how it is given (in one dose or continuous infusion).

IV infusion (5FU): When given in one dose (as a bolus), chest pain can occur during the infusion or a few hours afterward.

The continuous IV infusion is given over two to four days with a pump that you may take home. When given this way, the chemotherapy may reach certain parts of the body more slowly. Symptoms can occur between 12-72 hours after starting the infusion. With more cycles of continuous infusions, symptoms may begin earlier in the cycle, become more intense, and last longer.

Oral pill (capecitabine): The pill version, capecitabine, is processed by the body more slowly. As a result, the symptoms are like those experienced with continuous infusion. Side effects may be less intense and start 12-72 hours after starting the medicine.