What specific visual disturbances develop as part of the cinchonism syndrome?

Sources indicate only the general development of visual disturbances within cinchonism, without specifying their exact type.

What are the routes of administration for quinine in severe falciparum malaria?

In severe falciparum malaria, quinine is administered intravenously. Specifically, intravenous infusion of quinine dihydrochloride is given slowly, not exceeding a rate of twenty drops per minute.

Which antibiotics is quinine combined with to prevent *Plasmodium* resistance?

To treat chloroquine-resistant strains of falciparum malaria, quinine is combined with the antibiotic clindamycin. In high doses, this agent is actively used against Plasmodium species as part of specific therapeutic regimens.

What hematological complications can quinine administration cause?

Quinine administration can cause hematological complications in the form of acute erythrocyte hemolysis. In patients with a genetic deficiency of the erythrocyte enzyme glucose-6-phosphate dehydrogenase, this leads to acute hemolysis and hemolytic anemia. In addition, complications of therapy include massive intravascular hemolysis of red blood cells.

What is the source of quinine?

Quinine is a natural alkaloid obtained from the bark of the cinchona tree.

For which stage of malaria is quinine used?

The drug is used exclusively for the treatment of the erythrocytic stage of malaria and is not prescribed for prophylaxis.

What is 'cinchonism'?

It is a specific symptom complex of drug toxicity that includes tinnitus, deafness, headache, nausea, vomiting, and visual disturbances.

Home › Pharmacology › Quinine

Quinine

Chininum

For medical students2 min readUpdated 2026-10-10

Quinine is the oldest natural antimalarial drug, an alkaloid derived from the bark of the cinchona tree, used in medicine since 1632. The substance disrupts heme metabolism and blocks transcription processes in the malaria parasite.

OriginCinchona bark alkaloid

HistoryUsed in Europe since 1632

DNA ActionIntercalation into chains and transcription blockade

ToxicityDevelopment of 'cinchonism' syndrome and arrhythmias

Origin and Chemical Properties

Quinine is a natural alkaloid extracted from the cinchona bark. Historically, it is the oldest antimalarial agent, utilized in European medical practice since 1632.

Chemically, a close relative of the drug is quinidine. It acts as an optical isomer of quinine and exhibits a nearly identical spectrum of pharmacological properties.

Mechanism of Action

The antimalarial effect of the substance is achieved through several pathways:

Disruption of normal heme metabolism within the parasite.
Direct insertion (intercalation) into the Plasmodium DNA molecule via hydrogen bond formation.
Prevention of nucleic acid strand separation, leading to the inhibition of transcription and translation processes.

Clinical Use in Malaria

The drug has strict indications and limitations in modern therapy:

It is used exclusively for treatment of the disease.
It is employed only against the erythrocytic stage of malaria.
It is absolutely not used for disease prophylaxis.

Side Effects and Toxicity

The toxic effects of the compound manifest with specific symptoms:

Cinchonism: a complex of pathological signs including severe tinnitus, temporary deafness, pronounced headache, nausea, vomiting, and various visual disturbances.
Cardiotoxicity: the ability to provoke dangerous arrhythmias and cause QT interval prolongation on the electrocardiogram.

Frequently asked questions

What specific visual disturbances develop as part of the cinchonism syndrome?: Sources indicate only the general development of visual disturbances within cinchonism, without specifying their exact type.
What are the routes of administration for quinine in severe falciparum malaria?: In severe falciparum malaria, quinine is administered intravenously. Specifically, intravenous infusion of quinine dihydrochloride is given slowly, not exceeding a rate of twenty drops per minute.
Which antibiotics is quinine combined with to prevent *Plasmodium* resistance?: To treat chloroquine-resistant strains of falciparum malaria, quinine is combined with the antibiotic clindamycin. In high doses, this agent is actively used against Plasmodium species as part of specific therapeutic regimens.
What hematological complications can quinine administration cause?: Quinine administration can cause hematological complications in the form of acute erythrocyte hemolysis. In patients with a genetic deficiency of the erythrocyte enzyme glucose-6-phosphate dehydrogenase, this leads to acute hemolysis and hemolytic anemia. In addition, complications of therapy include massive intravascular hemolysis of red blood cells.
What is the source of quinine?: Quinine is a natural alkaloid obtained from the bark of the cinchona tree.
For which stage of malaria is quinine used?: The drug is used exclusively for the treatment of the erythrocytic stage of malaria and is not prescribed for prophylaxis.
What is 'cinchonism'?: It is a specific symptom complex of drug toxicity that includes tinnitus, deafness, headache, nausea, vomiting, and visual disturbances.

Go deeper

Structural relationship between quinine and its optical isomer quinidine
Detailed biochemical mechanism of heme polymerization disruption
Features of intercalation into Plasmodium DNA via hydrogen bonds
Criteria for cardiotoxicity and causes of QT interval prolongation
History of the introduction of cinchona bark into European medical practice since 1632