Source: PubMed

Petri M, Konig MF, Li J, Goldman DW. Higher Hydroxychloroquine Blood Levels Are Associated with Reduced Thrombosis Risk in Systemic Lupus Erythematosus. Arthritis Rheumatol. 2021 Jan 5.

doi: 10.1002/art.41621 Epub ahead of print. PMID: 33403833.



Hydroxychloroquine (HCQ) has a primary role in the prophylaxis and treatment of systemic lupus erythematosus (SLE) and may be protective against thrombosis in SLE. Optimal weight‐based dosing of HCQ is unknown. This study examined the usefulness of HCQ blood monitoring in predicting thrombosis risk in a longitudinal SLE cohort.


HCQ levels were serially quantified from EDTA whole blood by liquid chromatography‐tandem mass spectrometry. Mean HCQ blood levels calculated prior to thrombosis or until the last visit were compared between patients with and without thrombosis using t‐test. Pooled logistic regression was used to analyze the association between rates of thrombosis and HCQ blood level.


In 739 patients with SLE, thrombosis occurred in 38 patients (5.1%). Mean HCQ blood level was lower in patients who developed thrombosis vs without thrombosis (720±489 vs 935±580, p=0.025). Thrombosis rates were reduced by 12% for every 200 ng/mL increase in the most recent HCQ blood level (0.87 [0.78, 0.98], p=0.025) and by 13% for mean HCQ blood level (rate ratio 0.87 [0.76,1.00], p=0.056). Thrombotic events were reduced by 69% in patients with mean HCQ blood levels >1068 ng/mL vs <648 ng/mL (0.31 [0.11, 0.86], p=0.024). This remained significant after adjustment for confounders (0.34 [0.12, 0.94], p=0.037).


Low HCQ blood levels are associated with thrombotic events in SLE. Longitudinal measurement of HCQ levels may allow for personalized HCQ dosing strategies. Recommendations for empirical dose reduction may reduce or eliminate the benefits of HCQ in this high‐risk population.

Related: Adherence to Hydroxychloroquine Lowers Lupus Mortality

Hydroxychloroquine shows potential to target autoinflammatory component of CPRS

The results of a meta-analysis of 187 studies treating COVID-19 successfully with hydroxychloroquine are statistically irrefutable.

Top US medics recommend ‘sequenced multidrug therapy’ including HCQ & Ivermectin, for early high-risk COVID-19 infections

Share on facebook
Share on twitter
Share on whatsapp
On Trend

Latest Stories

Dr. Harvey Risch: Hydroxychloroquine, Ivermectin, and Other Therapeutics Highly Effective in Early COVID Treatment

I’ve railed against this in the media that we are a part of, and the way that the propaganda reacts to this is, “Ignore it. Ignore all of this.” I’m saying this now because the general public has to be the one that gets angry. The general public should be furious at the way people have been treated in the country by suppression of these drugs, by that kind of website that suppresses the ability of doctors to practice medicine.

Read More »

A Judge Stands up to a Hospital: “Step Aside” and Give a Dying Man Ivermectin

The judge’s finest moment may have been when he dashed the most glaring myth about ivermectin—that it is not safe, despite decades of use that shows otherwise. Noting that all drugs have side effects, Judge Fullerton listed ivermectin’s effects from a government website.
“(N)umber one, generally well tolerated; number two, dizziness; number three, pruritus; number four, nausea/diarrhea. These are the side effects for the dosage that’s being asked to be administered,” he said. “The risks of these side effects are so minimal that Mr. Ng’s current situation outweighs that risk by one-hundredfold.”

Read More »