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Quensyl: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Quensyl - General Information

A chemotherapeutic agent that acts against erythrocytic forms of malarial parasites.

 

Pharmacology of Quensyl

Quensyl possesses antimalarial actions and also exerts a beneficial effect in lupus erythematosus (chronic discoid or systemic) and acute or chronic rheumatoid arthritis. The precise mechanism of action is not known.

 

Quensyl for patients

 

Quensyl Interactions

 

Quensyl Contraindications

Use of this drug is contraindicated (1) in the presence of retinal or visual field changes attributable to any 4-aminoquinoline compound, (2) in patients with known hypersensitivity to 4-aminoquinoline compounds, and (3) for long-term therapy in children.

 

Additional information about Quensyl

Quensyl Indication

For the suppressive treatment and treatment of acute attacks of malaria due to Plasmodium vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum. It is also indicated for the treatment of discoid and systemic lupus erythematosus, and rheumatoid arthritis.

Mechanism Of Action
Although the exact mechanism of action is unknown, it may be based on ability of hydroxychloroquine to bind to and alter the properties of DNA. Quensyl has also has been found to be taken up into the acidic food vacuoles of the parasite in the erythrocyte. This increases the pH of the acid vesicles, interfering with vesicle functions and possibly inhibiting phospholipid metabolism. In suppressive treatment, hydroxychloroquine inhibits the erythrocytic stage of development of plasmodia. In acute attacks of malaria, it interrupts erythrocytic schizogony of the parasite. Its ability to concentrate in parasitized erythrocytes may account for their selective toxicity against the erythrocytic stages of plasmodial infection. As an antirheumatic, hydroxychloroquine is thought to act as a mild immunosuppressant, inhibiting the production of rheumatoid factor and acute phase reactants. It also accumulates in white blood cells, stabilizing lysosomal membranes and inhibiting the activity of many enzymes, including collagenase and the proteases that cause cartilage breakdown.
Generic Name
Hydroxychloroquine
Synonyms
2-((4-((7-Chloro-4-quinolyl)amino)pentyl)ethylamino)ethanol; Gen-Hydroxychloroquine 200mg Tablets; HCQ; Hidroxicloroquina [inn-spanish]; Hydroxychloroguine; Hydroxychloroquine sulfate; Hydroxychloroquinum [inn-latin]; Idrossiclorochina [dcit]; Oxichlorochinum; Oxichloroquine; Oxychlorochin; Oxychloroquine
Drug Category
Antimalarials; Antirheumatic Agents; Dermatologic Agents; Enzyme Inhibitors
Drug Type
Small Molecule; Approved
Other Brand Names containing Hydroxychloroquine
Ercoquin; Quensyl; Plaquenil;
Absorption
Very rapidly and completely absorbed following oral administration.
Toxicity (Overdose)
Symptoms of overdose include headache, drowsiness, visual disturbances, cardiovascular collapse, and convulsions, followed by sudden and early respiratory and cardiac arrest. The electrocardiogram may reveal atrial standstill, nodal rhythm, prolonged intraventricular conduction time, and progressive bradycardia leading to ventricular fibrillation and/or arrest.
Protein Binding
Approximately 45%.
Biotransformation
Partially hepatic, to active de-ethylated metabolites.
Half Life
Terminal elimination half-life In blood is approximately 50 days. In plasma it is approximately 32 days.
Dosage Forms of Quensyl
Tablet Oral
Chemical IUPAC Name
2-[4-[(7-chloroquinolin-4-yl)amino]pentyl-ethylamino]ethanol
Chemical Formula
C18H26ClN3O
Organisms Affected
Plasmodium