Hydroxychloroquine

Category: pharmacological

Aliases: Plaquenil, HCQ

Pharmacological Mechanism

Aminoquinoline antimalarial — accumulates in lysosomes raising endosomal pH. Disrupts antigen processing + Toll-like receptor signaling. Used long-term for SLE + rheumatoid arthritis. Retinopathy risk requires baseline + annual ophthalmologic monitoring.

Half-Life (t½)

PO: 960h

Dosing Guidelines

• PO: Typical 400 mg (Range: 200–600 mg)

Target Organ Systems

• immune-hematologic

Pathways It Modulates

• Anthelmintic + antiprotozoal targets (inhibitor) — heme polymerization (parasite digestive vacuole)
• cGAS-STING cytosolic DNA sensing → type I IFN (inhibitor) — lysosomal acidification (indirect ↓ TLR9 + cGAS-STING inputs)
• Neuroinflammation (inhibitor) — lysosomal acidification + TLR9 + cGAS-STING (autoimmune CNS — lupus)
• Pyroptosis (inhibitor) — NLRP3 / lysosomal disruption
• TLR (Toll-like receptor) innate signaling (inhibitor) — TLR7/9 (lysosomal acidification block)

Chemical Identifiers

• PubChem CID: 3652
• Formula: C18H26ClN3O
• Molecular weight: 335.87 g/mol
• InChIKey: XXSMGPRMXLTPCZ-UHFFFAOYSA-N
• SMILES: CCN(CCCC(C)NC1=C2C=CC(=CC2=NC=C1)Cl)CCO

References

• PMID 2757893