Chloroquine is a medication used primarily to treat and prevent malaria. It is also used to treat amebiasis, another parasitic infection. Chloroquine is sometimes used to treat chronic inflammatory and autoimmune disorders.
History
Chloroquine was discovered in 1934, but scientists mistakenly thought the drug was too toxic to warrant further testing. It was rediscovered during World War II in an effort to find new antimalarials to combat the disease among Allied troops.
Chemistry and Routes of Administration
Chloroquine belongs to the 4-aminoquinoline family of drugs. The drug comes in two forms: chloroquine phosphate and hydrochloride. The phosphate form is a tablet taken by mouth. The hydrochloride form is a liquid, which is administered by injection.
Therapeutic Uses
Chloroquine is a commonly used antimalaria drug. Malaria is contracted when a person is bitten by a mosquito infected with Plasmodium parasites. The Centers for Disease Control and Prevention (CDC) reports that malaria was eradicated in the U.S. in the early 1950's, but the disease continues to be a significant global problem. CDC recommends chloroquine to prevent malaria when traveling to high-risk areas with no reported chloroquine resistance.
The drug is also used to treat malaria. According to a 2007 review article published by CDC scientists in "The Journal of the American Medical Association," chloroquine is the drug of choice to treat acute attacks caused by susceptible strains of malaria.
Chloroquine is also used to treat another parasitic infection, amebiasis. Chloroquine is generally used in combination with other medicines to treat this condition.
Resistance
Dr. R.C. Mahajan noted in a review article published in 2004 that chloroquine resistance is "now found in all parts of the world where malaria is endemic." Although chloroquine resistance is geographically widespread, it is generally limited to only one of the four malaria-causing strains.
Warnings and Precautions
To determine if the benefits of chloroquine outweigh the potential risks, your doctor needs to know if you have a blood disorder, liver or kidney disease, hearing or vision problems, epilepsy, psoriasis or another skin disease. Chloroquine should not be taken if you are allergic to chloroquine or hydroxychloroquine. To avoid potential drug interactions, your doctor needs to know about all prescription and over-the-counter medicines and supplements you are taking.
According to the National Institutes of Health (NIH), "There are no adequate and well-controlled studies evaluating the safety and efficacy of chloroquine in pregnant women." Chloroquine is used during pregnancy only when the doctor has determined the benefits outweigh the potential risk to the fetus.
NIH states there is potential for serious adverse reactions in nursing infants from chloroquine. The benefits to the mother must be weighed against the potential risks to the baby on a case-by-case basis.
Because there is a risk of retinal damage with long-term use of chloroquine, regular eye exams are important. Chloroquine overdose can be fatal, especially in children. Take only the prescribed dose of chloroquine, and be sure to keep it out of the reach of children.
Side Effects and Adverse Reactions
The most common side effects of chloroquine are decreased appetite, nausea, vomiting, diarrhea and headache. Severe allergic reactions can occur with chloroquine. Seek immediate medical attention if you experience difficulty breathing, chest tightness, or swelling of the mouth, face, lips or tongue.
Other possible serious side effects of chloroquine include vision changes, hearing loss, muscle weakness, bizarre behavior, hallucinations, seizures and heart rhythm problems. Sensitivity to the sun, itching, hair loss and skin reactions may occur. Inform your doctor promptly if you experience a skin reaction that involves much of your skin or worsens over time. Uncommonly, chloroquine can affect your mental health. Depression, anxiety, difficulty sleeping and personality changes have been reported.
