Chloroquine and Hydroxychloroquine Interaction
Drug interaction information between Chloroquine and Hydroxychloroquine.
Chloroquine and Hydroxychloroquine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Chloroquine and Hydroxychloroquine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Both of these drugs can change the electrical rhythm of your heart. Taking them together increases the risk of a dangerous irregular heartbeat.
FDA Label Information
( 7 ) 7.1 Drugs Prolonging QT Interval and Other Arrhythmogenic Drugs Hydroxychloroquine sulfate tablets prolongs the QT interval. There may be an increased risk of inducing ventricular arrhythmias if hydroxychloroquine sulfate tablets are used concomitantly with other arrhythmogenic drugs. Therefore, hydroxychloroquine sulfate tablets are not recommended in patients taking other drugs that have the potential to prolong the QT interval or are arrhythmogenic [see Warnings and Precautions (5.1) ].
Chloroquine Also Interacts With
- Dapsone Topical moderate
- Lidocaine Topical moderate
- Remdesivir moderate
- Methylprednisolone minor
Hydroxychloroquine Also Interacts With
- Cimetidine moderate
- Heparin moderate
- Remdesivir moderate
- Methotrexate minor
- Cyclosporine minor
Frequently Asked Questions
What SPL severity band is on file for Chloroquine + Hydroxychloroquine?
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?
Hydroxychloroquine has 7 labeled pairs on file vs Chloroquine's 5. In the moderate band specifically: Chloroquine has 4 (also Dapsone Topical, Lidocaine Topical, Remdesivir); Hydroxychloroquine has 4 (also Cimetidine, Heparin, Remdesivir).
What mechanism field is on file for Chloroquine and Hydroxychloroquine?
Both of these drugs can change the electrical rhythm of your heart. Taking them together increases the risk of a dangerous irregular heartbeat.
Hydroxychloroquine's labeled portfolio outnumbers Chloroquine
SPL source-record counts only. This page's band is moderate · classes on file: Chloroquine (Antimalarial); Hydroxychloroquine (Disease-Modifying Antirheumatic Drug (DMARD)).
0 major · 4 moderate · 1 minor · 5 total
- Other moderate peers for Chloroquine
- Dapsone Topical
- Lidocaine Topical
- Remdesivir
0 major · 4 moderate · 3 minor · 7 total
- Other moderate peers for Hydroxychloroquine
- Cimetidine
- Heparin
- Remdesivir
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.
Read our methodology - how this data is sourced, computed, and verified.