Avloquin 250mg Tablet – Chloroquine for Malaria, Lupus & Insulin Sensitization

1. Chloroquine in Bangladesh: Malaria Treatment and Resistance Patterns

Avloquin 250mg, manufactured by ACI Limited, contains chloroquine phosphate 250mg (equivalent to 150mg chloroquine base) per tablet. Chloroquine was the original first-line antimalarial for over five decades. In Bangladesh, malaria remains endemic primarily in the Chittagong Hill Tracts (CHT) — Rangamati, Khagrachari, and Bandarban districts — where Plasmodium falciparum and P. vivax are the predominant species. Chloroquine resistance in P. falciparum is now widespread globally, including in Bangladesh, making chloroquine unsuitable as monotherapy for falciparum malaria in most settings. However, chloroquine remains effective for P. vivax malaria, which constitutes a significant proportion of malaria cases in CHT. National guidelines: artemisinin-based combination therapy (ACT) is first-line for P. falciparum; chloroquine remains first-line for uncomplicated P. vivax in Bangladesh where chloroquine-resistant P. vivax has not yet been confirmed.

2. Chloroquine as a Disease-Modifying Drug in Lupus and Rheumatoid Arthritis

Beyond malaria, chloroquine and its analogue hydroxychloroquine (HCQ) are used as disease-modifying antirheumatic drugs (DMARDs) in autoimmune conditions. In Bangladesh, chloroquine 250mg is used (hydroxychloroquine being less widely available) for: (1) Systemic Lupus Erythematosus (SLE): Chloroquine reduces disease activity, protects against lupus flares, reduces end-organ damage (particularly lupus nephritis), and reduces mortality. Current EULAR guidelines recommend HCQ (or chloroquine if HCQ unavailable) in all SLE patients unless contraindicated. Dose: 2.5mg/kg/day of chloroquine base; (2) Rheumatoid arthritis: Used as monotherapy for mild RA or in combination with methotrexate for moderate-severe RA. Reduces joint inflammation and erosion. Requires 3–6 months to achieve full anti-inflammatory effect; (3) Malaria prophylaxis for travellers to chloroquine-sensitive malaria zones. In SLE patients, chloroquine also reduces cardiovascular risk and thrombosis, making it one of the most broadly beneficial medications in lupus management.

3. Chloroquine, Insulin Sensitization, and Relevance to Diabetes

Research interest in chloroquine for metabolic conditions stems from its inhibition of lysosomal degradation of insulin-receptor complexes — effectively prolonging insulin receptor signalling. Clinical evidence: (1) Insulin sensitization: Chloroquine inhibits the enzyme insulin-degrading enzyme (IDE) and enhances insulin sensitivity in type 2 diabetes patients in several small studies; (2) SLE patients with diabetes: SLE patients on long-term chloroquine/HCQ have significantly lower rates of type 2 diabetes compared to those not on these drugs — a consistent finding across multiple cohort studies; (3) HbA1c reduction: In diabetic patients with SLE or RA, hydroxychloroquine (closely related to chloroquine) lowers HbA1c by 0.4–0.7% and reduces fasting glucose; (4) Not a diabetes treatment: Chloroquine is not approved for type 2 diabetes management and should not be used outside of its licensed indications. However, patients with autoimmune conditions and co-existing type 2 diabetes may benefit from the metabolic effects of their DMARD therapy.

4. Dosage

Malaria treatment (P. vivax): Chloroquine base 25mg/kg over 3 days — typically 4 tablets (600mg base) day 1, 2 tablets (300mg base) day 2, 2 tablets day 3. Take with food to reduce GI side effects. Malaria prophylaxis: 300mg base (2 tablets) once weekly, starting 1–2 weeks before travel, continuing 4 weeks after leaving endemic area. SLE/RA: 150–250mg base daily (1–2 tablets). Maximum dose based on ideal body weight to limit retinal toxicity: do not exceed 2.5mg/kg/day of chloroquine base. Long-term use: requires baseline ophthalmology assessment and annual eye review from year 5 onwards.

5. G6PD Deficiency: Important Screening Before Use

Chloroquine can cause haemolytic anaemia in patients with G6PD (glucose-6-phosphate dehydrogenase) deficiency — an inherited enzyme deficiency common in malaria-endemic populations including Bangladesh. G6PD deficiency prevalence in Bangladesh is estimated at 5–8% in males (X-linked). Clinical relevance: (1) Malaria patients with G6PD deficiency who require chloroquine — haemolysis risk is moderate (lower than primaquine); chloroquine is generally considered safe in G6PD deficiency at standard antimalarial doses; (2) Primaquine (given alongside chloroquine for P. vivax radical cure to eliminate liver hypnozoites) carries HIGH haemolysis risk in G6PD deficiency — G6PD testing is mandatory before prescribing primaquine; (3) Long-term chloroquine in autoimmune conditions in G6PD-deficient patients: monitor haemoglobin periodically.

Frequently Asked Questions (FAQ)

Q1: Is chloroquine still effective for malaria in Bangladesh?

For Plasmodium vivax malaria (common in Chittagong Hill Tracts), chloroquine remains effective first-line treatment in Bangladesh, as chloroquine-resistant P. vivax has not been confirmed there. For Plasmodium falciparum malaria, chloroquine resistance is widespread — artemisinin-based combination therapy (ACT) is required. Species-specific diagnosis (blood film or RDT distinguishing P. falciparum from P. vivax) is essential before prescribing chloroquine. For travellers returning from areas outside Bangladesh with confirmed P. falciparum, never use chloroquine alone.

Q2: Can people with diabetes safely take chloroquine?

Yes — with monitoring. Chloroquine can lower blood glucose by enhancing insulin sensitivity. In patients with type 2 diabetes taking insulin or sulfonylureas, chloroquine may increase the risk of hypoglycaemia. Monitoring recommendations: (1) Monitor blood glucose more frequently when starting chloroquine; (2) Inform your diabetes doctor and pharmacist that you are starting chloroquine; (3) If you experience sweating, tremor, or dizziness on chloroquine combined with diabetes medicines, check blood sugar — these may be hypoglycaemia symptoms; (4) Dose adjustment of diabetes medication may be required. For malaria prophylaxis doses (weekly), the hypoglycaemia risk is lower than with daily therapeutic doses.

Q3: What eye checks are needed for long-term chloroquine use?

Chloroquine can cause retinal toxicity (chloroquine retinopathy) — irreversible damage to the retina — with long-term use at higher doses. Risk is low at doses ≤2.5mg/kg/day of chloroquine base and cumulative duration under 5 years. Monitoring: (1) Baseline ophthalmology assessment before starting or within 1 year of starting long-term chloroquine; (2) Annual eye review from year 5 (or earlier if risk factors: renal impairment, pre-existing retinal disease, high dose); (3) Investigations: visual field testing, spectral-domain OCT (SD-OCT), and multifocal ERG; (4) Early retinopathy: parafoveal deposits visible on OCT before visual symptoms develop — the importance of annual screening is detection before vision loss occurs. Report any new visual symptoms (blurred vision, difficulty reading, photosensitivity) immediately.

Q4: Why did chloroquine gain attention during COVID-19 and was it effective?

Chloroquine and hydroxychloroquine were proposed as potential COVID-19 treatments in early 2020 based on in vitro (laboratory) evidence that they inhibit viral entry into cells by raising endosomal pH. However, large, well-designed randomised controlled trials (RECOVERY trial, WHO SOLIDARITY trial) definitively showed that chloroquine and hydroxychloroquine are NOT effective for COVID-19 treatment. They do not reduce mortality, hospital admission, or duration of illness in COVID-19 patients. The initial laboratory findings did not translate to clinical benefit. Chloroquine should not be obtained or used for COVID-19. Its established indications remain malaria, SLE, and RA.