- Guide to PHARMACOLOGY
Synonyms: Dolquine® | Plaquenil®
hydroxychloroquine is an approved drug (FDA (1955))
Compound class: Synthetic organic
Comment: Hydroxychloroquine is a 4-aminoquinoline and used primarily as an antimalarial drug.
The approved drug is a racemic mixture and we show the chemical structure without stereochemistry to represent the mixture. The non-isomeric structure is also represented in the PubChem, ChEMBL and ChEBI entries listed in the links table below, while the two enantiomers forming the racemate are represented by PubChem CID 178395 and PubChem CID 178396.
The marketed formulations contain hydroxychloroquine sulfate (PubChem CID 3044369).
Activity at non-malarial protein targets:
Although this drug has direct effects on survival of the malaria parasite it also appears to be an antagonist of two of the human TOLL-like receptors (TLR7 and TLR9). Antagonism of these receptors is likely related to the anti-inflammatory action of this drug in some auto-immune diseases.
Activity against SARS-CoV-2:
Hydroxychloroquine exhibits in vitro antiviral activity against both the original SARS coronavirus (SARS-CoV)  and SARS-CoV-2 which emerged in 2019 . Preliminary evidence from a small clinical trial indicates that hydroxychloroquine reduces detectable virus in COVID-19 patients, and that this effect is enhanced by co-treatment with the antibiotic azithromycin (article in press, to be published in International Journal of Antimicrobial Agents, available pre-release via DOI: 10.1016/j.ijantimicag.2020.105949. It is predicted that this effect could be the result of a combination of the drug's antiviral action and its established anti-inflammatory efficacy . In addition to cardiovascular adverse effects associated with hydroxychloroquine (and also with chloroquine) treatment, another restriction to the widespread use of hydroxychloroquine against COVID-19 should be that there is as yet no convincing (statistically significant) evidence to support therapeutic or prophylactic efficacy against this infection. High quality randomised controlled studies will be an essential component of further clinical efforts.
Ligand Activity Visualisation Charts
These are box plot that provide a unique visualisation, summarising all the activity data for a ligand taken from ChEMBL and GtoPdb across multiple targets and species. Click on a plot to see the median, interquartile range, low and high data points. A value of zero indicates that no data are available. A separate chart is created for each target, and where possible the algorithm tries to merge ChEMBL and GtoPdb targets by matching them on name and UniProt accession, for each available species. However, please note that inconsistency in naming of targets may lead to data for the same target being reported across multiple charts.✖
View more information in the IUPHAR Pharmacology Education Project: hydroxychloroquine
|Compound class||Synthetic organic|
|Ligand families/groups||Antimalarial ligands|
|Approved drug?||Yes (FDA (1955))|
|WHO Essential Medicine||WHO Model List of Essential Medicines (21st List, 2019). Access PDF version.|
|International Nonproprietary Names|
|Dolquine® | Plaquenil®|
|CAS Registry No.||118-42-3|
|GtoPdb PubChem SID||178103773|
|Search Google for chemical match using the InChIKey||XXSMGPRMXLTPCZ-UHFFFAOYSA-N|
|Search Google for chemicals with the same backbone||XXSMGPRMXLTPCZ|
|Search PubMed clinical trials||hydroxychloroquine|
|Search PubMed titles||hydroxychloroquine|
|Search PubMed titles/abstracts||hydroxychloroquine|
|Search UniChem for chemical match using the InChIKey||XXSMGPRMXLTPCZ-UHFFFAOYSA-N|
|Search UniChem for chemicals with the same backbone||XXSMGPRMXLTPCZ|
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Cat. No. 5648