Never, ever take Hydroxychloroquine without consulting your doctor first, ever. Every chloroquine derivative carries a high overdose potential, and it has numerous interactions with other drugs.
Taken by those with hypertension, it can lead to dangerous arrhythmia of the heart, as well as thinning and tearing of arterial walls.
In fact, never take any controlled substance without first consulting a medical professional. That includes any of the other “wonder drugs” that are hitting the market.