Hydroxychloroquine and Chloroquine Interaction
Drug interaction information between Hydroxychloroquine and Chloroquine.
Hydroxychloroquine and Chloroquine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Hydroxychloroquine and Chloroquine. 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) ].
Hydroxychloroquine Also Interacts With
- Cimetidine moderate
- Heparin moderate
- Remdesivir moderate
- Methotrexate minor
- Cyclosporine minor
Chloroquine Also Interacts With
- Dapsone Topical moderate
- Lidocaine Topical moderate
- Remdesivir moderate
- Methylprednisolone minor
Frequently Asked Questions
What SPL severity band is on file for Hydroxychloroquine + Chloroquine?
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: Hydroxychloroquine has 4 (also Cimetidine, Heparin, Remdesivir); Chloroquine has 4 (also Dapsone Topical, Lidocaine Topical, Remdesivir).
What mechanism field is on file for Hydroxychloroquine and Chloroquine?
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: Hydroxychloroquine (Disease-Modifying Antirheumatic Drug (DMARD)); Chloroquine (Antimalarial).
0 major · 4 moderate · 3 minor · 7 total
- Other moderate peers for Hydroxychloroquine
- Cimetidine
- Heparin
- Remdesivir
0 major · 4 moderate · 1 minor · 5 total
- Other moderate peers for Chloroquine
- Dapsone Topical
- Lidocaine Topical
- 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.