Bismuth Subsalicylate and Doxycycline Hyclate Interaction

Drug interaction information between Bismuth Subsalicylate and Doxycycline Hyclate.

Bismuth Subsalicylate and Doxycycline Hyclate have a documented minor interaction in FDA labeling.

FDA drug labeling documents a minor-severity interaction between Bismuth Subsalicylate and Doxycycline Hyclate. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.

Drug A

Bismuth Subsalicylate

Antidiarrheal / Antacid

Drug B

Doxycycline Hyclate

Tetracycline Antibiotic (Antimalarial)

How They Interact

Bismuth subsalicylate stops your body from absorbing doxycycline into your blood. This can prevent the antibiotic from working to kill bacteria.

FDA Label Information

Absorption of tetracyclines is impaired by bismuth subsalicylate.

Bismuth Subsalicylate Also Interacts With

View all Bismuth Subsalicylate interactions →

Frequently Asked Questions

What SPL severity band is on file for Bismuth Subsalicylate + Doxycycline Hyclate?

Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.

Which drug in this pair has the larger labeled-interaction portfolio?

Doxycycline Hyclate has 5 labeled pairs on file vs Bismuth Subsalicylate's 3. In the minor band specifically: Bismuth Subsalicylate has 3 (also Doxycycline, Omadacycline); Doxycycline Hyclate has 4 (also Doxycycline, Carbamazepine, Phenytoin).

What mechanism field is on file for Bismuth Subsalicylate and Doxycycline Hyclate?

Bismuth subsalicylate stops your body from absorbing doxycycline into your blood. This can prevent the antibiotic from working to kill bacteria.

Doxycycline Hyclate's labeled portfolio outnumbers Bismuth Subsalicylate

SPL source-record counts only. This page's band is minor · classes on file: Bismuth Subsalicylate (Antidiarrheal / Antacid); Doxycycline Hyclate (Tetracycline Antibiotic (Antimalarial)).

Bismuth Subsalicylate

0 major · 0 moderate · 3 minor · 3 total

Doxycycline Hyclate

0 major · 1 moderate · 4 minor · 5 total

Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.