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Aralen (Chloroquine) Information

Aralen (chloroquine) is a 4-aminoquinoline derivative used primarily as an antimalarial and historically as an anti-inflammatory agent. It is the first-line and highly effective treatment for malaria caused by chloroquine-sensitive strains of Plasmodium species, including P. falciparum, P. vivax, P. ovale, and P. malariae. Chloroquine is a blood schizonticide, meaning it acts rapidly to kill the asexual parasites circulating in the red blood cells, which are responsible for the acute, symptomatic stage of the disease. While replaced mainly in inflammatory conditions by its analog, hydroxychloroquine (Plaquenil), chloroquine was historically used to treat rheumatoid arthritis and lupus erythematosus. Chloroquine is generally well-absorbed orally and has a long terminal half-life, allowing for once-weekly prophylactic dosing. Prophylaxis typically begins 1 to 2 weeks before exposure and continues for 4 weeks after leaving the endemic area.

The mechanism of action for chloroquine primarily involves its concentration within the acidic food vacuole of the intraerythrocytic malaria parasite. The parasite degrades the host hemoglobin to obtain amino acids for survival, which releases the toxic heme molecule. The parasite polymerizes, typically, this poisonous heme into non-toxic hemozoin. Chloroquine interferes with this process by binding to the heme, preventing its polymerization. The resulting accumulation of free, toxic heme oxidizes the parasite's membranes, leading to cell lysis and death. The drug is less effective against the dormant liver stages (hypnozoites) of P. vivax and P. ovale (requiring co-administration with primaquine for radical cure). It only kills the gametocytes (sexual stages) of P. vivax, P. ovale, and P. malariae, but not P. falciparum.

Aralen Side Effects

Chloroquine is generally well-tolerated at prophylactic doses, but side effects, particularly those affecting the central nervous system (CNS) and eyes, can occur, especially at higher or chronic doses. Common side effects often include gastrointestinal issues such as nausea, vomiting, abdominal cramps, and diarrhea. Severe vomiting may be a sign of acute toxicity or may compromise the efficacy of the dose. Other frequent, but usually transient, effects are headache, dizziness, itching (pruritus), and difficulty focusing the eyes. Taking the medication after meals can often reduce gastrointestinal distress.

However, more serious side effects can occur, particularly with prolonged use or acute overdose. The medication carries a Boxed Warning for the risk of fatal overdose, especially in children, and for the risk of irreversible retinopathy. If any of the following symptoms are experienced, the patient should stop taking the medication and seek immediate medical attention:

• Cardiotoxicity: Rare but severe cardiotoxicity, including cardiomyopathy (damage to the heart muscle) and cardiac arrhythmias (especially bundle branch block and QT prolongation), has been reported, sometimes resulting in heart failure.

• Hypoglycemia (Severe): Chloroquine can cause profound and sometimes life-threatening hypoglycemia, including loss of consciousness, particularly in patients taking other antidiabetic drugs.

• Neuropsychiatric Events: Acute psychosis, seizures, and severe anxiety have been reported, often requiring discontinuation of the drug.

• Ocular Toxicity (Retinopathy) (Boxed Warning): Chloroquine can cause irreversible damage to the retina, specifically the macula (chloroquine retinopathy), which can lead to permanent vision loss. The risk is dose- and duration-dependent. Regular ophthalmologic monitoring is mandatory for long-term therapy.

• Ototoxicity: Hearing loss and tinnitus (ringing in the ears) have been reported, which may be permanent.

Aralen Precautions

A detailed discussion of medical history is necessary before initiating chloroquine therapy, especially given the Boxed Warning regarding the risk of fatal overdose in children, for whom the drug must be stored securely and away from reach. Due to the risk of irreversible retinopathy, patients beginning long-term therapy should undergo a baseline ophthalmologic exam, including visual acuity, fundus examination, and visual field testing. They should then have regular follow-up exams. If the patient reports any new visual disturbances, the drug must be immediately stopped. Chloroquine is generally contraindicated in patients with known hypersensitivity to 4-aminoquinoline compounds and in the presence of pre-existing maculopathy or retinal damage. Caution must be exercised in patients with pre-existing hepatic disease or alcoholism, as the liver extensively metabolizes chloroquine, and dosage adjustment may be needed. Due to the risk of cardiotoxicity, patients with underlying cardiac conditions, such as known arrhythmias or bundle branch block, require extreme caution and often require ECG monitoring before and during therapy. Due to the potential for severe hypoglycemia, caution is advised when administering chloroquine to patients on antidiabetic medications, and blood glucose levels should be monitored closely. Chloroquine must be used cautiously in patients with G6PD deficiency, as it may, rarely, induce mild hemolysis, and in patients with psoriasis or porphyria, as it may exacerbate these conditions. Because chloroquine can cause muscle weakness and potentially affect nerve conduction, it should be used with caution in patients with myasthenia gravis.

Do I need a prescription to order Aralen?

Yes, a prescription is required from your physician to order Aralen.