chloroquine phosphate

Action and Spectrum

Actions and Spectrum: 

Mechanism of Action:  

chloroquine phosphate primarily interferes with the parasite’s ability to digest and utilize hemoglobin, a protein found in red blood cells. It accumulates within the parasite’s digestive vacuole, raising the pH level and inhibiting the activity of enzymes involved in hemoglobin degradation. As a result, the parasite cannot obtain essential nutrients from hemoglobin, leading to its death. 

Additionally, it is believed to inhibit the parasite’s ability to detoxify toxic heme molecules, which are released during hemoglobin digestion. This leads to the accumulation of toxic heme within the parasite, causing oxidative damage and further contributing to its demise.  

Spectrum of Activity:  

It is effective against a variety of Plasmodium species, including: 

Plasmodium falciparum is the most common and deadly species causing malaria in humans. chloroquine phosphate was once highly effective against P. falciparum, but resistance has developed in many regions over time, limiting its usefulness in treating this species. 

Plasmodium vivax: chloroquine phosphate remains effective against P. vivax, another species causing malaria. It is commonly used for the treatment of uncomplicated P. vivax infections. 

Plasmodium malariae: chloroquine phosphate is also effective against P. malariae, another species causing human malaria. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Macular degeneration 

Nyctalopia 

Stevens-Johnson syndrome 

Pancytopenia 

Reversible agranulocytosis 

Delirium 

Agitation 

Confusion 

Maculopathy 

Visual disturbances 

Erythema multiforme 

Toxic epidermal necrolysis 

Aplastic anemia 

Psychosis 

Anxiety 

Insomnia 

Hallucinations 

Black Box Warning

Black box warning: 

None 

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

• Hypersensitivity: Individuals with known hypersensitivity or allergy to chloroquine or its components should not use the medication. 
• Retinopathy: chloroquine phosphate has the potential to cause retinopathy, a condition that affects the retina of the eye.  
• G6PD Deficiency: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a hereditary condition affecting red blood cells. chloroquine phosphate can trigger hemolysis (breakdown of red blood cells) in individuals with this deficiency, leading to severe complications.  
• Porphyria: Porphyria refers to a group of rare genetic disorders that affect heme production, a hemoglobin component. chloroquine phosphate can potentially worsen porphyria symptoms or trigger an acute attack.  
• Severe liver disease: Individuals with severe liver disease, such as liver failure, should avoid using chloroquine phosphate due to the potential for decreased drug clearance and increased risk of toxicity. 
• Severe renal impairment: chloroquine phosphate is primarily eliminated through the kidneys, so individuals with severe renal impairment or end-stage renal disease may have difficulty excreting the drug properly.  

Caution: 

• Gastrointestinal Disorders: chloroquine phosphate can cause gastrointestinal side effects such as nausea, vomiting, diarrhea, and abdominal cramps.  
• Cardiac Disorders: chloroquine phosphate can potentially prolong the QT interval, leading to a severe heart rhythm disorder known as torsades de pointes.  
• Neurological Disorders: It can rarely cause central nervous system effects, such as seizures or psychosis.  
• Blood Disorders: It can affect blood cells, including reducing the number of white blood cells, red blood cells, and platelets. 
• Dermatological Disorders: It can cause skin reactions, including rashes and photosensitivity.

Pregnancy / Lactation

Pregnancy consideration: It should be used with caution during pregnancy 

Lactation: Excretion of the drug in human breast milk is unknown 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

• Antimalarial activity: chloroquine phosphate primarily acts against the malaria parasite Plasmodium spp. It accumulates in the acidic vacuoles of the parasite, disrupting the detoxification of toxic heme molecules released during the digestion of host hemoglobin. This leads to the accumulation of toxic heme, oxidative damage, and subsequent death of the parasite.  
• Anti-inflammatory and Immunomodulatory Effects: chloroquine phosphate has been found to possess anti-inflammatory properties. It can inhibit the production and release of pro-inflammatory cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). This makes it useful in certain autoimmune and inflammatory conditions, including rheumatoid arthritis and systemic lupus erythematosus (SLE).  
• Inhibition of Autophagy: It is known to inhibit autophagy, a cellular process involved in the recycling and degradation of cellular components. By inhibiting autophagy, chloroquine can affect various cellular processes and has been investigated for its potential use in treating certain cancers. 
• Antiviral activity: It has demonstrated broad-spectrum antiviral activity against several viruses, including certain strains of the coronavirus family. It is thought to interfere with viral replication and entry into host cells. 

Pharmacokinetics: 

Absorption 

chloroquine phosphate is well absorbed after oral administration, with a bioavailability of approximately 89%. The peak plasma concentration of chloroquine is reached within 1-2 hours after administration. 

Distribution 

chloroquine phosphate is distributed widely in body tissues, including the eyes, heart, kidneys, liver, and lungs. It can cross the placenta and enter breast milk, potentially affecting the fetus or nursing infant. 

Metabolism 

chloroquine phosphate undergoes partial metabolism in the liver. 

Elimination and Excretion 

The elimination half-life of chloroquine phosphate is approximately 3-5 days. It is primarily eliminated from the body through the urine, with around 70% of the drug excreted unchanged. Acidification of urine can increase the elimination of chloroquine. 

Adminstartion

Administration: 

Oral Administration 

chloroquine phosphate is available in tablet or oral suspension forms. The tablets should be swallowed whole with water and taken with or after meals to minimize gastrointestinal side effects. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: chloroquine phosphate 

Why do we use chloroquine phosphate? 

chloroquine phosphate has several uses across different medical conditions. Here are some common uses of chloroquine: 

• Malaria: It is primarily used to prevent and treat malaria, a mosquito-borne infectious disease caused by the Plasmodium parasite.  
• Rheumatoid Arthritis and Systemic Lupus Erythematosus (SLE): It is sometimes prescribed for treating autoimmune conditions such as rheumatoid arthritis and systemic lupus erythematosus (SLE). It can help reduce inflammation and alleviate symptoms in these conditions. 
• Amoebic Liver Abscess: chloroquine phosphate, in combination with other medications, can be used for the treatment of amoebic liver abscess, which is a severe infection of the liver caused by the amoeba Entamoeba histolytica. 
• Extraintestinal Amebiasis: chloroquine phosphate, along with other medications, may be used to treat extraintestinal amebiasis, which occurs when the amoeba Entamoeba histolytica spreads from the intestines to other organs such as the liver, lungs, or brain.