Clarithromycin and Itraconazole Interaction

Drug interaction information between Clarithromycin and Itraconazole.

Clarithromycin and Itraconazole have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Clarithromycin and Itraconazole. 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

Clarithromycin

Macrolide Antibiotic

Drug B

Itraconazole

Azole Antifungal

How They Interact

These two drugs interfere with each other's breakdown in the body, which can cause the levels of both to rise. This makes it more likely that you will experience side effects from either drug.

FDA Label Information

Antifungals: Itraconazole Use With Caution Itraconazole: Both clarithromycin and itraconazole are substrates and inhibitors of CYP3A, potentially leading to a bi-directional drug interaction when administered concomitantly (see also Itraconazole under “Drugs That Affect Clarithromycin Tablets” in the table below). Clarithromycin may increase the plasma concentrations of itraconazole. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions.

Frequently Asked Questions

What SPL severity band is on file for Clarithromycin + Itraconazole?

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

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

Itraconazole has 116 labeled pairs on file vs Clarithromycin's 81. In the moderate band specifically: Clarithromycin has 35 (also Omeprazole, Methylprednisolone, Sildenafil, Valproate); Itraconazole has 20 (also Tamsulosin, Rivaroxaban, Tenofovir Disoproxil, Glecaprevir/Pibrentasvir).

What mechanism field is on file for Clarithromycin and Itraconazole?

These two drugs interfere with each other's breakdown in the body, which can cause the levels of both to rise. This makes it more likely that you will experience side effects from either drug.

Itraconazole carries more major-labeled pairs than Clarithromycin

SPL source-record counts only. This page's band is moderate · classes on file: Clarithromycin (Macrolide Antibiotic); Itraconazole (Azole Antifungal).

Itraconazole has 19 major-labeled pairs vs Clarithromycin's 16. This page itself is in the moderate band, not the major band.

Clarithromycin

16 major · 35 moderate · 30 minor · 81 total

Itraconazole

19 major · 20 moderate · 77 minor · 116 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.