What is the interaction between oral chemotherapy and gastroesophageal reflux disease (GERD) medicines? —Name withheld on request

Some oral chemotherapy medications such as dasatinib (Sprycel) or erlotinib (Tarceva) are best absorbed in the presence of acid. Many medications used for the management of GERD suppress acid excretion in the stomach (eg, the proton pump inhibitor [PPI] omeprazole [Prilosec] or the H2 receptor antagonist [H2RA] famotidine [Pepcid]) or neutralize acid (eg, the antacid calcium carbonate [Tums, others]). By reducing the acid in the stomach and subsequently in the GI tract, PPIs, H2RAs or antacids can reduce absorption of some affected oral chemotherapy medications by more than 50%.1

In some instances, patients may require acid suppressing therapy while receiving treatment with an affected oral chemotherapy agent. In these cases, GERD medication and timing should be selected carefully. Traditional antacids such as calcium carbonate, separated from the oral chemotherapy drug by at least 2 hours, are preferred due to their short duration of effects.1

In some cases, an H2RA may be acceptable due to its intermittent duration of effects, particularly if the oral chemotherapy drug is given once daily. The H2RA should be taken at least 10 hours before and 2 hours after the oral chemotherapy. For example, if erlotinib is taken at 10 am, the famotidine could be taken between noon and midnight.2

PPIs are best avoided in patients taking affected oral chemotherapy medications due to their long-lasting acid suppressing effects; the patient’s oncologist may need to be advised if shorter-acting medications do not control the patient’s GERD symptoms.

References

1. Sprycel [package insert]. Princeton, NJ: Bristol-Myers Squibb Company; October 2015.

2. Tarceva [package insert]. South San Francisco, CA: Genentech USA, Inc; 2016.