Chloroquine

What is Chloroquine?

Chloroquine is a synthetic antimalarial medicine belonging to the 4-aminoquinoline class. First developed in the 1930s and widely adopted following World War II, it is one of the oldest medicines used in travel health. While resistance has significantly reduced its global utility for malaria prevention, Chloroquine remains relevant for specific travel destinations where malaria parasites retain sensitivity to the drug, subject to current destination-specific guidance.

Chloroquine is also used in clinical medicine to manage certain autoimmune conditions, including rheumatoid arthritis and systemic lupus erythematosus (SLE), though this page focuses on its role in travel health and malaria prophylaxis.

How does Chloroquine work?

Chloroquine acts primarily against blood-stage malaria parasites. It accumulates within the parasite’s digestive vacuole and interferes with the detoxification of haem — a toxic byproduct of haemoglobin digestion. By inhibiting the formation of haemozoin (the non-toxic form of haem), Chloroquine causes haem to accumulate to toxic levels within the parasite, ultimately killing it.

Chloroquine is effective against the asexual (blood-stage) forms of sensitive Plasmodium species. It does not eliminate dormant liver-stage parasites (hypnozoites) of P. vivax and P. ovale, which are responsible for malaria relapse — a doctor must assess separate anti-relapse treatment, including the relevant G6PD safety testing.

Who is Chloroquine for?

Chloroquine prophylaxis is appropriate for travellers visiting specific malaria-endemic regions where the local Plasmodium strains retain sensitivity to Chloroquine. Current travel guidance restricts its use to destinations with sensitive parasites.

Travellers should obtain a current destination-specific risk assessment before departure, as resistance patterns can shift. An independent doctor reviewing your travel health assessment will consider:

• Your specific destination(s) and itinerary
• Duration and type of travel (urban vs. rural, accommodation type)
• Your full medical history and current medications
• Any contraindications to Chloroquine or alternative antimalarials

Chloroquine is not recommended for destinations with documented widespread Chloroquine-resistant P. falciparum malaria, including most of sub-Saharan Africa, Southeast Asia, and parts of South America. Malarone, Doxycycline, or Lariam are typically preferred for these regions.

Dosage

The following is the CDC adult prophylaxis schedule for chloroquine phosphate in US guidance, not a universal Spanish product dose:

Spanish Resochín contains 250 mg diphosphate equivalent to 155 mg base per tablet. Its adult label specifies 310 mg base (2 tablets) weekly, starting 1 week before exposure and continuing for 4 weeks after leaving. Do not convert between products using the CDC salt/base convention. Take the prescribed product on the same day each week, after food.

Dosing for children is weight-based and must be determined by a qualified medical professional. This page does not constitute prescribing advice.

Side effects

Effects described in the Spanish Resochín label

Nausea, vomiting, diarrhoea, abdominal pain and some visual disturbances are common. Headache, dizziness, confusion and sleep disturbance are uncommon; itching, rashes and retinal damage are among the rarer effects. Frequency varies by reaction and exposure.

Serious reactions

• Eye damage: Retinal injury can be irreversible. Report visual changes promptly. For prolonged treatment, the label requires an eye examination before starting and every 3 months, and blood counts before starting and every 2 months.
• Heart effects: QT prolongation and cardiomyopathy can occur. Fainting, palpitations or signs of heart failure require urgent assessment.
• Severe hypoglycaemia: Dangerously low blood glucose, including loss of consciousness, can occur with or without diabetes medicines. Seek urgent help for symptoms such as confusion or fainting.
• Blood, skin and psychiatric reactions: Serious blood disorders, severe skin reactions and psychiatric symptoms, including suicidal thoughts, require prompt medical attention.

Chloroquine vs alternatives

The choice of antimalarial depends heavily on your travel destination and individual medical circumstances. The table below is for informational purposes only.

Online assessment for Chloroquine

Prescrivia is a technology intermediary connecting patients with independent doctors and licensed pharmacies. We do not provide medical services, prescribe, employ doctors, sell or dispense medicines.

1. Assessment: Provide your symptoms or travel plans, medical history and all current medicines.
2. Independent review: A doctor decides whether a prescription is clinically appropriate; Prescrivia does not guarantee a prescription.
3. Dispensing: Any lawful dispensing is the responsibility of a licensed pharmacy, subject to the applicable rules and product availability.

In Spain, distance selling of prescription medicines is prohibited. An online assessment or a product label does not establish that a medicine can legally be supplied or delivered through this platform. This information does not change eligibility or fulfilment rules.

Important safety information

Do not take Resochín if you have: hypersensitivity to chloroquine, related 4-aminoquinolines or excipients; retinopathy or visual-field impairment; blood-forming system disorders; G6PD deficiency; or myasthenia gravis. Its label also prohibits specified interacting combinations, including halofantrine; a prescriber must check the complete medication list.

Avoid use in psoriasis or porphyria. Do not use chloroquine to prevent malaria where parasites are resistant.

Tell your doctor: about epilepsy, kidney or liver impairment, heart rhythm disorders and all medicines. Antacids and kaolin must be separated by at least 4 hours. Other interactions include QT-prolonging drugs, antiepileptics, digoxin, ciclosporin and glucose-lowering medicines.

Pregnancy and breastfeeding: Resochín is contraindicated except for the label’s malaria treatment/short-term prevention exception, which requires individual benefit–risk assessment. The label advises contraception during prophylaxis and for 3 months afterwards, and interruption of breastfeeding during use. Do not interpret the malaria exception as blanket pregnancy or breastfeeding reassurance.

Sources

• AEMPS: Resochín 155 mg, product information
• CDC Yellow Book: Malaria, US travel guidance
• BOE: Real Decreto Legislativo 1/2015, article 3.5

This is information, not individual prescribing advice. Seek urgent medical assessment for fever during or after travel to a malaria-risk area, even if you took prevention.

Medical information on this page is based on the following sources:

• World Health Organization (WHO). International Travel and Health: Malaria. who.int
• European Medicines Agency (EMA). Product information for Chloroquine-containing medicines. ema.europa.eu
• WHO. Guidelines for the Treatment of Malaria, 3rd edition. Geneva: WHO, 2015.
• Centers for Disease Control and Prevention (CDC). Malaria: Choosing a Drug to Prevent Malaria. cdc.gov

This content is provided for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for advice relevant to your individual health circumstances and travel plans.